Radiology Signs

Radiological sign	description	Section
Spleen normal	Splenic size is variable depending on age, nutrition, and patient size; normal 12x4x7 cm; splenic volume Apxtransversexsuperior-inferior /2; normal <150g br=""> Acessory spleens are common; failure of fusion, usually <3cm accessory="" br="" don="" enhances="" for="" like="" mistake="" nodes="" round="" spleen="" spleens="" t=""> Lobulations are common; clefts cause lobulations, dont mistake clefts for lacerations or infarcts 10 HU less then liver Variable enhancements due to the variable circulatory routes through the spleen; white pulp (lyphatic follicles and RE cells); Redpulp (interspersed vascular lakes) Patterns of enhancement: serpentine, cord like enhancement most common - more pronounced with fast injection rates; exagerated in certain patients - decreased cardiac output or heart failure, splenic vein occlusion, portal hypertension; becomes uniform on delayed scans Splenic artery anatomy: the average number of branches to the spleen originating 3-13cm from the hilum is between 6 and 12 and is called the distributed pattern A magistral type of branching consists of a long splenic artery that divides near the hilum into 3 or 4 short terminal branches	Anatomy
Circumscribed masses with well-defined borders	Circumscribed masses with well-defined borders (>75% circumference): uncommon sign of malignancy; only 2% of solitary masses with smooth margins are malignant.	Breast Imaging
Inverted teardrop	• Inverted teardrop: nonspecific sign seen with extensive gel bleed or focal intracapsular rupture; occurs when silicone enters radial fold and then leaks between internal and external capsules	Breast Imaging
linguini sign by MRI	• Flaps (“linguini sign” by MRI) may represent intracapsular rupture.	Breast Imaging
Skin thickening (>3 mm)	Skin thickening (>3 mm) may be a sign of malignancy or benign conditions. Types: Focal: local tumor Diffuse: sign of edema; may be due to inflammatory cancer	Breast Imaging
Spiculated tumor margin	• Spiculated: a spiculated tumor margin is the only specific sign of malignancy; however, not all spiculated masses are cancers. Spiculated masses are the easiest masses to diagnose, although they may be obscured by fibroglandular tissue. Spiculations are also seen in: Scar tissue (usually resolves in 1 year if a surgical scar and in 3 years if a postradiation scar) Desmoid tumors Fat necrosis	Breast Imaging
Calcification of coronary arteries	Calcification of coronary arteries are the most reliable plain film sign of CAD (90% specificity in symptomatic patients), but calcified coronary arteries are not necessarily stenotic.	Cardiac Imaging
Figure-3 sign	Pseudocoarctation	Cardiac Imaging
Gated CT Chest	Retrospective or prospective ECG gated minimize motion artifact from the beating heart; Use of gating enables coronary artery and aortic valve evaluation Indication: anterior chest pain and suspicion of ascending aortic disection requires gating; Coronary artery evaluation - coronary artery disease Functional Valve Imaging requires retrospective cardiac gating Retrospective imaging - functional evaluation prospective ECG gated - limited by CT scan type; lower dose of radiation;	Cardiac Imaging
LV aneurysm	LV aneurysm is the second most reliable plain film sign of CAD. It develops in 20% MI.	Cardiac Imaging
Normal Aortic Valve	64-detectot cardiac CT performed with prospective ECG gating may have similar subjective image quality and substantially lower patient radiation dose compared with retrospective ECG gating (Radiology) Gating Pitfalls: Incorrect pitch during gating; Incorrect ECG pulsing window Incorrect pitch - pitch calculated according to baseline heart rate; patients heart rate may vary during inspiration and contrast administration; results in application of incorrect pitch Wrong ECG Pulsing widow: ECG based dose modulation - lower dose during noncritical segment of R-R interval; if the heart rate changes or window is too tight; low tube current being applied during the critical portion of the cardiac cycle; image quality is reduced;	Cardiac Imaging
Oreo cookie sign on lateral view	Oreo cookie sign on lateral view: Subpericardial fat stripe measures >10 mm (a stripe 1 to 5 mm can be normal). Pericardial effusion	Cardiac Imaging
Reverse-3 sign of barium-filled esophagus	Coarctation of aorta	Cardiac Imaging
Scimitar sign.	Partial anomalous pulmonary venous connection (PAPV C) • The anomalous vein of the infracardiac type looks like a Turkish scimitar (sword): scimitar sign.	Cardiac Imaging
Water-bottle sign	Symmetrical enlargement of cardiac silhouette (water-bottle sign) Pericardial effusion	Cardiac Imaging
Air crescent sign in cavity	This sign was originally described in aspergillosis and is most commonly seen there. More recently, the sign has also been described with other entities: • Mucormycosis • Actinomycosis • Septic emboli • Klebsiella pneumoniae infection • TB • Tumors Invasive aspergillosis - • Within 2 weeks, 50% of nodules undergo cavitation, which results in the air crescent sign. The appearance of the air crescent sign indicates the recovery phase (increased granulocytic response). Note that the air crescent sign may also be seen in TB, actinomycosis, mucormycosis, septic emboli, and tumors. Do not confuse the air crescent sign with the Monod sign (clinical history helps to differentiate).	Chest Imaging
Atoll sign	Atoll sign (ring-shaped opacity) COP - Cryptogenic organizing pneumonia (COP)	Chest Imaging
Bilateral Pulmonary Hypoplasia	Pulmonary hypoplasia in the neonate can be unilateral or bilateral. Bilateral pulmonary hypoplasia is most often the result of compression of the lungs during fetal development. Congenital bone dysplasias and syndromes associated with hort ribs and a small thoracic cage (asphyxiating thoracic dystrophy, thanatophoric dwarfism, Ellis-van Creveld syndrome) compress the lungs and cause hypoplastic lungs. The degree of hypoplasia is often severe and leads to the demise of these infants. Chromosomal abnormalities such as the trisomies are associated with hypoplastic lungs, and in some infants, hypoplasia is “primary” and unexplained.	Chest Imaging
Black pleura sign	Pulmonary alveolar microlithiasis - Sandlike microcalcifications of lung (black pleura sign)	Chest Imaging
Cheerio sign	Bronchioloalveolar carcinoma Cavitation may be seen by HRCT (Cheerio sign)	Chest Imaging
Comet sign	Comet sign: bronchi and vessels curve toward the mass, seen in Round Atelectasis of asbestosis	Chest Imaging
Comet tail sign of vessel leading to atelectatic lung	bronchioloalveolar carcinoma Cavitation may be seen by HRCT (Cheerio sign)	Chest Imaging
Continuous diaphragm sign	Continuous diaphragm sign: due to air trapped posterior to pericardium	Chest Imaging
Deep sulcus sign	Pneumothorax Deep sulcus sign: anterior costophrenic angle sharply delineated	Chest Imaging
Double bronchial wall sign	Pneumomediastinum - Air outlining bronchial wall: double bronchial wall sign	Chest Imaging
Early sign of asbestos-related disease	Benign pleural effusion is an early sign of asbestos-related disease	Chest Imaging
Extrapleural sign	Air between parietal pleura and diaphragm: extrapleural sign	Chest Imaging
Flattening of hemidiaphragms (reliable sign)	Overinflation • Flattening of hemidiaphragms (reliable sign): highest level of the dome is <1 .5="" a="" above="" and="" between="" cm="" costophrenic="" drawn="" junctions.="" line="" nbsp="" straight="" td="" the="" vertebrophrenic="">	Chest Imaging
Fleischner sign	Fleischner sign: increased diameter of pulmonary artery (>16 mm) seen in acute PE. It usually disappears within a few days.	Chest Imaging
Golden inverted “S” sign in RUL, LUL collapse	Secondary Signs of Malignancy (Fig. 1-33) • Atelectasis (Golden inverted “S” sign in RUL, LUL collapse) • Obstructive pneumonia • Pleural effusion • Interstitial patterns: lymphangitic tumor spread • Hilar and mediastinal adenopathy • Metastases to ipsilateral, contralateral lung	Chest Imaging
Hampton hump	Hampton hump: triangular peripheral cone of infarct = blood in secondary pulmonary lobules (rare); does not grow → should reduce in size on successive radiographs	Chest Imaging
Monod sign	• Air may surround the aspergilloma (Monod sign), mimicking the appearance of cavitation seen with invasive aspergillosis.	Chest Imaging
Ring around artery sign	Pneumomediastinum - Air around pulmonary artery and main branches: ring around artery sign	Chest Imaging
Signet ring sign	Bronchiectasis Thickened walls Signet ring sign: focally thickened bronchial wall adjacent to pulmonary artery branch	Chest Imaging
Split pleura sign (CT, MRI):	Pulmonary edema - Split pleura sign (CT, MRI): loculated fluid between visceral and parietal pleura with thickening of pleura. Thickened pleura may enhance with IV contrast.	Chest Imaging
Thymic sail sign	Pneumomediastinum - Elevated thymus: thymic sail sign	Chest Imaging
Tubular artery sign	Air outlining major aortic branches: tubular artery sign Pneumomediastinum -	Chest Imaging
Westermark sign: localized pulmonary oligemia (rare)	Pulmonary Embolism Westermark sign: localized pulmonary oligemia (rare)	Chest Imaging
‘3’ sign.	Chest radiograph in a patient with coarctation. There is rib notching and enlargement of the left subclavian artery, causing a ‘3’ sign.	Chest Imaging
Approach to diffuse lung disease	?	Chest Imaging
Continuous diaphragm’ sign	EXTRAPULMONARY AIR Causes Iatrogenic, blunt or penetrating trauma ▶ barotrauma CXR/CT • Pneumomediastinum: linear air densities streaking within the mediastinum ▶ a visible thymus ▶ air seen anterior to the pericardium ▶ ring-like lucencies due to air surrounding a pulmonary artery § ‘Double bronchial wall’ sign: air on either side of a bronchial wall § ‘Continuous diaphragm’ sign: air over a diaphragmatic surface	Chest Imaging
CT signs of diaphragmatic rupture dependent viscera sign thick crus sign collar sign	MDCT diagnosis of diaphragmatic rupture is largely based on the fact that abdominal organs are seen in the pleural space outside the diaphragm. The more usual CT signs of diaphragmatic rupture include: discontinuity of the diaphragm with direct visualization of the diaphragmatic injury; herniation of abdominal organs with liver, bowel or stomach in contact with the posterior ribs (‘dependent viscera sign’); thickening of the crus (‘thick crus sign’); constriction of the stomach or bowel (‘collar sign’); active arterial extravasation of contrast material near the diaphragm; and, in the case of a penetrating diaphragmatic injury, depiction of a missile or puncturing instrument trajectory.	Chest Imaging
Deep sulcus’ sign	‘Deep sulcus’ sign: an unusually deep costophrenic sulcus (as air preferentially accumulates anterior to the lungs and also abuts mediastinal structures in the supine position)	Chest Imaging
dilatation of the bronchi,	The major sign of bronchiectasis on thin-collimation CT (highresolution CT [HRCT]) is dilatation of the bronchi, with or without bronchial wall thickening. Bronchial dilatation on CT is often manifested by lack of tapering of bronchial lumina (the cardinal sign of bronchiectasis) 16.8), internal bronchial diameter greater than that of the adjacent pulmonary artery (signet ring sign)	Chest Imaging
Displaced crus sign: Diaphragm sign: Interface sign: Bare area sign:	CT signs which may differentiate pleural effusion and ascites. Scans through lower thorax/upper abdomen in patient with bilateral pleural effusions and ascites. (A) Displaced crus sign: The right pleural effusion collects posterior to the right crus of the diaphragm and displaces it anteriorly. Diaphragm sign: The pleural fluid is over the outer surface of the dome of the diaphragm, whereas the ascitic fluid is within the dome. (B) Interface sign: The interface (arrows) between the liver and ascites is usually sharper than between liver and pleural fluid. Bare area sign: Peritoneal reflections prevent ascitic fluid from extending over the entire posterior surface of the liver in contrast to pleural fluid in the posterior costophrenic recess.	Chest Imaging
Double bronchial wall’ sign:	EXTRAPULMONARY AIR Causes Iatrogenic, blunt or penetrating trauma ▶ barotrauma CXR/CT • Pneumomediastinum: linear air densities streaking within the mediastinum ▶ a visible thymus ▶ air seen anterior to the pericardium ▶ ring-like lucencies due to air surrounding a pulmonary artery § ‘Double bronchial wall’ sign: air on either side of a bronchial wall § ‘Continuous diaphragm’ sign: air over a diaphragmatic surface	Chest Imaging
Double diaphragm’ sign	‘Double diaphragm’ sign: visualization of the undersurface of the heart PNEUMOTHORAX	Chest Imaging
dumb-bell-shaped mass extending through the foramina posterior vertebral body scalloping T2WI: the ‘target’ sign	PERIPHERAL NERVE TUMOURS • These originate from a paravertebral intercostal nerve within the posterior mediastinum • Benign: § Neurofibroma, § Schwannoma (neurilemmoma): • Malignant: § Nerve sheath tumours (neurogenic sarcomas): these are rare RADIOLOGICAL FEATURES Benign tumours CXR A well-defined round or oval posterior mediastinal mass ▶ any pressure deformity causes a smooth, scalloped indentation on the adjacent ribs, vertebral bodies (dural ectasia causes posterior vertebral body scalloping), pedicles or transverse processes ▶ there is preservation of the scalloped cortex (which is often thickened) ▶ the adjacent rib spaces are widened NECT A widened intervertebral foramina in 10% (with an associated dumb-bell-shaped mass extending through the foramina) ▶ homogeneous or heterogeneous appearance (  punctate foci of calcification) ▶ generally < 2 vertebral bodies long CECT Heterogeneous enhancement MRI T1WI: variable SI (similar to the spinal cord) ▶ T2WI: the ‘target’ sign: a characteristic high SI peripherally with low SI centrally ▶ T1WI and Gad: uniform enhancement	Chest Imaging
Epicardial fat pad ‘sign’	The epicardial fat pad ‘sign’ is positive when, visualized in the lateral projection, an anterior pericardial stripe (bordered by epicardial fat posteriorly and mediastinalfat anteriorly) is thicker than 2 mm. This sign is diagnostic of pericardial thickening or fluid	Chest Imaging
Garland’s triad (‘1-2-3’ sign)	Sarcoidosis Symmetrical hilar lymphadenopathy (in almost all cases) ▶ this is the most common cause of intrathoracic lymphadenopathy ▶ the anterior nodes occasionally increase in size (posterior nodal enlargement is very unusual) • Garland’s triad (‘1-2-3’ sign): symmetrical hilar adenopathy and right paratracheal adenopathy	Chest Imaging
Hampton’s hump’	• ‘Hampton’s hump’: a peripheral area of wedge-shaped consolidation secondary to infarction • Westermark sign: regional oligaemia with a sharp cutoff due to a pulmonary embolism	Chest Imaging
Hilar Convergence Sign	? Less then a cm of the pulmonary artery is seen, meaning that the mass is in the hilum (cuan)	Chest Imaging
hilar overlay’ sign	PERICARDITIS	Chest Imaging
Increased radiolucency of the ipsilateral hemithorax	Pneumothorax: this is often under tension with contralateral mediastinal shift ▶ frequently the pleural air lies anterior and medial to the lung and is more difficult to diagnose (with the only sign being an increased radiolucency of the ipsilateral hemithorax) ▶ often there is increased sharpness of the mediastinal border which, unlike with a pneumomediastinum, extends from the superior extent of the lung to the diaphragm ▶ a pneumothorax compresses the thymus (rather than being elevated as seen with a pneumomediastinum)	Chest Imaging
Inferior rib notching	Arterial: Coarctation of the aorta, aortic thrombosis, subclavian obstruction, any cause of pulmonary oligaemia Venous: Superior vena cava obstruction Arteriovenous: Pulmonary arteriovenous malformation, chest wall arterial malformation Neurogenic: Neurofibromatosis (ribbon ribs)	Chest Imaging
Luftsichel” sign	“Luftsichel”: radiolucency in upper lung zone that results from upward migration of superior segment of the left lower lobe (LLL)	Chest Imaging
Pressure erosion of a rib due to a neurofibroma.	Neurofibromatosis type 1 (NF-1): skeletal findings. Pressure erosion of a rib due to a neurofibroma. (Most rib deformities in NF-1 are due to the skeletal dysplasia, not pressure erosion.)	Chest Imaging
Signs that suggest a pneumothorax	Signs that suggest a pneumothorax • ipsilateral transradiancy, either generalized or hypochondrial • a deep, finger-like costophrenic sulcus laterally • a visible anterior costophrenic recess seen as an oblique line or interface in the hypochondrium; when the recess is manifest as an interface it mimics the adjacent diaphragm (‘double diaphragm sign’) • a transradiant band parallel to the diaphragm and/or mediastinum with undue clarity of the mediastinal border • visualization of the undersurface of the heart, and of the cardiac fat pads as rounded opacities suggesting masses • diaphragm depression.	Chest Imaging
Superior rib notching	Connective tissue diseases: Rheumatoid arthritis, SLE, Sjo¨gren’s, scleroderma Metabolic: Hyperparathyroidism Miscellaneous: Neurofibromatosis, restrictive lung disease, poliomyelitis, Marfans syndrome, osteogenesis imperfecta, progeria	Chest Imaging
Tension Pneumothorax	Moderate or gross mediastinal shift, should be taken as indicating tension, particularly if the ipsilateral hemidiaphragm is depressed (reliable).	Chest Imaging
the anterior and posterior junction lines	Since both junction lines are inconsistently seen, however, the lack of visualization of one or both is not a reliable sign of disease.	Chest Imaging
tree-in-bud sign	Small centrilobular nodular and linear branching opacities (tree-in-bud sign) express inflammatory and infectious bronchiolitis	Chest Imaging
Upper lobe blood diversion:	Upper lobe blood diversion: this is a normal finding on supine XRs – therefore it is not a useful sign in an ITU patient PULMONARY OEDEMA	Chest Imaging
water lily sign, camalote sign rising sun sign, serpent sign empty cyst sign ‘air bubble’ sign	Hydatid Cysts an air–fluid level, A floating membrane (water lily sign, camalote sign), a double wall, an essentially dry cyst with crumpled membranes lying at its bottom (rising sun sign, serpent sign), a cyst with all its contents expectorated (empty cyst sign) High specificity of CT for the diagnosis of perforated pulmonary hydatid cyst (‘air bubble’ sign) has been reported. Rupture into the pleural space causes an effusion or, if there is additional airway communication, a hydropneumothorax. The diagnosis may be established by serological testing, or examination of the sputum if there is rupture into airways.	Chest Imaging
Westermark sign	• ‘Hampton’s hump’: a peripheral area of wedge-shaped consolidation secondary to infarction • Westermark sign: regional oligaemia with a sharp cutoff due to a pulmonary embolism	Chest Imaging
Accordion sign	• Contrast between thickened folds (accordion sign) Pseudomembranous colitis (PMC)	Gastrointestinal Imaging
Bull's eye pattern (hypoechoic halo around lesion)	LIVER US FOR METASTASIS Echogenic metastases • GI malignancy • HCC • Vascular metastases Hypoechoic metastases • Most metastases are hypovascular. • Lymphoma • Bull's eye pattern (hypoechoic halo around lesion) Nonspecific sign but frequently seen in bronchogenic carcinoma Hypoechoic rim represents compressed liver tissue and tumor fibrosis. Calcified metastases: hyperechoic with distal shadowing • All mucinous metastases: colon > thyroid, ovary, kidney, stomach Cystic metastases: necrotic leiomyosarcoma; mucinous metastases	Gastrointestinal Imaging
Carman's (meniscus) sign*	*Results from the fluoroscopically induced apposition of rolled halves of the tumor margin forming the periphery of the ulcerated carcinoma; meniscus refers to meniscoid shape of ulcer. Malignant Peptic Ulcer	Gastrointestinal Imaging
Central dot sign	The “central dot sign” is a very specific sign of Caroli disease in which portal radicals are partially or completely surrounded by abnormally dilated and ectatic bile ducts on both sonography and CT.	Gastrointestinal Imaging
Colon cutoff sign	Barium: colon cutoff sign acute pancreatitis	Gastrointestinal Imaging
Comb sign	• Comb sign: vasa recta stretched out along one wall of colon Crohn disease (regional enteritis)	Gastrointestinal Imaging
Courvoisier's sign	Courvoisier's sign (enlarged, nontender GB), 25% Adenocarcinoma (PDAC) of pancreas	Gastrointestinal Imaging
Crohn-Stierlin sign like deep ulcers of Infectious Colitis	Campylobacter SU, DU Usually in distal colon Amebiasis SU, DU Diffuse but most severe in right colon (ameboma); small bowel rarely affected Tuberculosis DU Loss of demarcation between cecum and terminal ileum (Stierlin sign); lymph nodes Lymphogranuloma venereum DU Rectal strictures typical Yersinia DU Typically terminal ileum, cecum	Gastrointestinal Imaging
CT Bowel Target Sign	• Ischemia • Vasculitis • Hemorrhage • Inflammatory bowel disease • Angioedema: ACEi, hereditary, allergic reaction • Portal hypertension • NSAIDs	Gastrointestinal Imaging
CT Bowel Target Sign	CT Bowel Target Sign • Ischemia • Vasculitis • Hemorrhage • Inflammatory bowel disease • Angioedema: ACEi, hereditary, allergic reaction • Portal hypertension • NSAIDs	Gastrointestinal Imaging
CT of the Acute Abdomen	Most common reason for ER visits overall, CT is rapid, minimally invasive, high resolution imaging that can quickly direct patients towardds further treatment when results are positive and provide reassurance for practitioners (from a clinical and legal perspective) when results are negative. (Larson, Radiology 2011; 258:164-173) A negative study is not an unneccessary study. Reduce hospital admission 24%, leads to more timely surgery of patients 11%, ruled out significant disorders 26%, and provided an alternative diagnosis for the patients symptoms 26% (Rosen, AJR 2000)	Gastrointestinal Imaging
Cullen's sign	Periumbilical ecchymosis (Cullen's sign)	Gastrointestinal Imaging
Cystic fibrosis	AP radiograph in a newborn with cystic fibrosis shows numerous dilated bowel loops typical of a low intestinal obstruction. A bubbly appearance is noted in left lower quadrant bowel loops  related to gas mixing with meconium. PA water-soluble contrast enema ishows a mildly small sigmoid and descending colon with transition at the splenic flexure to a normal proximal colonic caliber. Note the numerous meconium plugs in the proximal colon.	Gastrointestinal Imaging
Dilatation of smaller venous branches (>5 mm) of pancreas	Dilatation of smaller venous branches (>5 mm): an indirect sign of venous encasement	Gastrointestinal Imaging
Double duct sign	Ductal obstruction in pancreatic adenocarcinoma • Pancreatic duct obstruction; pseudocysts are rare. • Common bile duct obstruction with pancreatic duct obstruction (double duct sign: also seen with pancreatitis) • Tumors in the uncinate process may not cause ductal obstruction. Double-duct sign: dilated biliary vessel accompanies portal veins.	Gastrointestinal Imaging
Double-duct sign: dilated biliary vessel accompanies portal veins.	Ultrasound Signs of Intrahepatic Bile Duct Dilatation Double-duct sign: dilated biliary vessel accompanies portal veins.	Gastrointestinal Imaging
Double-rim sign	• Double-rim sign: pericyst, endocyst Echinococcus (hydatid disease)	Gastrointestinal Imaging
Double-target sign	• Double-target sign: wall enhancement with surrounding hypodense zone (edema) 30% contain gas Pyogenic abscess	Gastrointestinal Imaging
Duodenal Wind Sock Sign	Duodenal wind sock sign in a patient with duodenal diverticulum. Image from an upper gastrointestinal series clearly demonstrates an intraluminal duodenal diverticulum (arrows) surrounded by a narrow radiolucent line (arrowheads). The diverticulum, arising in the second portion of the duodenum and extending to the third portion, was confirmed at surgery.	Gastrointestinal Imaging
Fleischner's sign	• Marked hypertrophy: ileocecal valve (Fleischner's sign) Intestinal tuberculosis (TB) • TB: narrow cecum (Fleischner's sign), narrow Crohn's may produce same appearance, terminal ileum (Stierlin's sign)	Gastrointestinal Imaging
Focal liver lesions	cystic lesions	Gastrointestinal Imaging
Focal liver lesions	hypervascular liver lesions I: Hemangioma: female predominance, hepatic artery vascular supply, peripheral nodular globular interupted enhancement with progressive centripital fill-in, large lesions can demonstrate a central scar or calcification, unencapsulated. Typical type hemangioma and Giant type hemangioma >5cm Focal Nodular Hyperplasia: young female, composed of varying degrees of hepatocytes, bile ducts and Kuppfer cells - will take up Tc-99m Sulfer Colloid, - will take up Eovist on delayed hepatic phase Multiple in 1/4 of cases Blood supply entirely from the hepatic artery (like hemangioma) - seen as a hypertrophied feeding vessel to the mass but no internal hypervascularity, homogeneously hypervascular (to IVC level enhancement) - no internal neovascularity of tumor vessels (cf adenomas or HCC) - Stelth lesions (cant find them on venous fase) -flower morphology - well circumscribed homogenous (cf HCC) - hypertrophied feeding vessel to center (without substantial neovascularity) Oftern invisible in the venous phase 50%deonstarate central scar (esp. when large) -scar can enhance on delayed images No capsule Hepatic Adenoma: female predominance; highly associated with Oral Contraceptive Pill use, steroids, steatosis, and glycogen storage disease; can present with hemorrhage in 20%; Primarily composed of hepatocytes and Kuppfer cells (no bile duct component so wont take up Eovist); Hepatic "adenomatosis" without OCP use; Malignant degeneration to HCC is rare.  Hepatic artery vascular supply; heterogeneously hypervascular on the arterial phase - fat - hemorrhage; variable appearance on the venous phase and delayed images (washout/isodense/hypodense); oftern encapsulated on venous and delayed images; can have a central scar - underlying history is critical, uable to distinguish from HCC or hypervascular metastasis without a specific history	Gastrointestinal Imaging
Focal liver lesions	hypervascular liver lesions II: Hepatocellular Carcinoma: 3rd leading cause of death worldwide; strong male predilection; Risk factors Hepatitis B and C, Cirrhosis, Fatty Liver; Management options - surgery, chemoembolisation, transplant MDCT sensitivity for HCC is >90%; Sensitivity for lesions <2cm -="" br="" diffuse="" false="" for="" increase="" lesions="" multifocal="" patterns="" positives="" small="" solitary="" three=""> Hypervascular in the arterial phase, homogeneous for lesions <3cm a="" br="" can="" capsule="" central="" delayed="" encapsulated="" enhancement="" fat="" have="" hemorrhage="" images="" in="" internal="" of="" on="" or="" phase="" scar="" the="" venous="" washout="" with=""> Protocol: arterial phase is critical - late arterial (30 to 35 seconds) preferred; delayed images may be useful - 14 % of HCC only seen on delayed images, typically well differenciated HCC's HCC Criteria for liver transplant Milan Criteria: Single lesion <5cm 3="" 3cm="" br="" disease="" invasion="" lesions="" liver="" metastatic="" no="" outside="" smaller="" the="" then="" vascular=""> UCSF Criteria: Single lesion les then 6.5cm; 3 lesions smaller then 4.5cm; No vascular lesions invasion; No metastatic disease outside the liver Fibrolamellar HCC: Young patient without hx of cirrhosis; theoretically less aggressive; large, lobulated aggressive looking; hypervascular with delayed washout, encapsulated, central scar Ca++; adenopathy common Vascular Shunts: do not confuse perfusion abnormalities with HCC, peripheral; wedge shaped; central vessel sign; increasingly common with cirrhosis. Be caucious in dealing with small hypervascular foci <6mm 3-6="" be="" followed="" for="" in="" increase="" months="" represent="" say="" should="" shunts="" size="" small="" statistically="" td="" that="" vascular="">	Gastrointestinal Imaging
Focal liver lesions	Solid liver masses I : Metastases: hypovascular and hypervascular; cholangiocarcinoma; lymphoma; epitheliod hemangioendothelioma liver metastases is the most common site of solid organ metastases; most common hepatic metastases are hypovascular; most common lesions colon, lung, breast, pancreas, neuroendocrine, melanoma, stomach; 50% of colorectal carcinoma  patientspet, or biopsy; dont assume these lesions are benign Approach to small hepatic hypodensities: When dealing with a lesion that is >15mm in  size should be able to distinguish benign from malignant lesions; these lesions may need further characterised with MRI, PET, or biopsy; dont assume lesions are benign. In a patient WITHOUT an underlying malignancy, <15mm 100="" ajr="" are="" as="" benign="" br="" follow="" is="" lesion="" mri="" necessary.="" no="" ones="" or="" report="" up=""> In a patient with known malignancy, only 12.7% are malignant, 80% remain benign (Schwarts). Dont overcall small lesions, pay attention to lesion morphology, look for hypervascularity at the rim of the lesion / surrounding lesions, solid component, nodularity, or perilesional edema; worry more about multiple lesions; follow lesions over time if they are truly "too small to characterise" Hypervascular metastasis: "MR CT PET" Melanoma, Renal cell carcinoma, Choriocarcinoma, Thyroid cancer, PET-Pancreatic + Neuroendocrine Tumour; use MIP images to identify subtle lesions. Require Arterial phase images, good indication for MIP imaging, Cholangiocarcinoma;	Gastrointestinal Imaging
Focal liver lesions	Solid liver masses II : Cholangiocarcinoma: tumor arising from the bile duct epithelium; 95% adenocarcinoma; Associated PSC, choledochal cysts, drug exposures (such as thoratrast), congenital hepatic fibrosis, viral hepatitis 3 forms of cholangiocarcinoma: Intrahepatic: mass forming intrahepatic cholangiocarcinoma; periductal infiltrating cholangiocarcinoma - segmental or lobar enhancing tissue in liver intraductal cholangiocarcinoma: ductal lumen Hilar Colangiocarcinoma arise from the confluence: Extrahepatic cholangiocarcinoma that arise from common bile duct: Variable appearance, peripheral hypervascularity on arterial phase images (and sometimes venous phase), hypovascular lesions, avid delayed enhancement, dilaed bile ducts (with bile thickening) in a lobar or segmental distribution, capsular retraction, lobar or segmental atrophy Hepatic lymphoma: primary lymphoma is rare; usually secondary lymphoma involvement; poorly enhancing solid or multiple masses; look for lymphadenopathy. Look for abdominal lymphadenopathy, splaying of vessels instead of coming together of vessels Epitheliod Hemangioendothelioma: Multiple hypodense lesions at the periphery; confluent lesions; capsular retaraction; peripheral enhancement with "ring or target" morphology	Gastrointestinal Imaging
Grey Turner's sign	GI hemorrhage, metabolic abnormalities, flank ecchymosis (Grey Turner's sign)	Gastrointestinal Imaging
Halo sign	Mural and Extramural Changes (CT Findings) • Circumferential submucosal low attenuation surrounded by higher outer attenuation: halo sign Crohn disease (regional enteritis)	Gastrointestinal Imaging
Hampton's line: 1- to 2-mm lucent line around the ulcer†	†This line is caused by thin mucosa overhanging the crater mouth seen in tangent; it is a reliable sign of a benign ulcer, but present in very few patients.	Gastrointestinal Imaging
Hirschsprung Disease (HD)	Hirschsprung Disease (HD) Anteroposterior fluoroscopic spot radiograph scout in an infant with infrequent stooling shows moderate to large stool load without other specific abnormality. The bones appear normal. AP radiograph shows multiple dilated loops of bowel throughout abdomen, most consistent with a distal bowel obstruction. There are no calcifications, free air, pneumatosis, or soft tissue masses. AP contrast enema shows the catheter has been removed. There is less spasm, but there is still a small rectum. RS ratio < 1.  The initially distended lateral view of the colon to the splenic flexure is the key view for a well-performed enema. Lateral contrast enema shows a narrow rectum with transition to the dilated colon at the rectosigmoid junction consistent with Hirschsprung disease. Note the spasm in the distal segment. Lateral contrast enema shows borderline RS ratio, meconium within the small left colon, and a transition zone at the splenic flexure (black open), suggesting MPS. Symptoms did not improve, and biopsy was performed in this pathologically proven HD. Often presents at birth with distal bowel obstruction Contrast enema primary findings Rectosigmoid ratio < 1 Transition most commonly sigmoid Transition often missed if at anorectal verge; enema misinterpreted as normal Other supporting CE findings Distal colonic spasm Colitis Irregular contractions Mucosal irregularity Delayed evacuation Total colonic Hirschsprung Small colon without transition ± intraluminal terminal ileal calcification Higher incidence in Down syndrome, especially total colonic disease Radiologic transition not equivalent to histologic transition, especially in long-segment HD	Gastrointestinal Imaging
light bulb sign of a hypervascular lesion—and its feeding vessel	Fibrous nodular hyperplasia: enhancement after intravenous administration of a microbubble contrast agent.	Gastrointestinal Imaging
Lightbulb sign	• Hyperintense (similar to CSF) on heavily T2W sequences (lightbulb sign) Hemangioma	Gastrointestinal Imaging
Liver overlap sign	• Liver overlap sign: overlaps lower margin of liver Volvulus	Gastrointestinal Imaging
Meconium Ileus	Meconium Ileus: microcolon; obstruction is usually in the terminal ileum; associated with cystic fibrosis AP radiograph in a newborn with bilious emesis shows a paucity of bowel gas centrally with displacement of gas-containing bowel to the left abdomen, suggestive of a central mass or fluid collection. No free air or air fluid levels; no calcifications to suggest perforation. AP radiograph in a newborn with failure to pass meconium shows numerous dilated bowel loops, typical of a distal obstruction. While the size and location of some of the loops could suggest colon, these loops were all dilated small bowel. Lateral radiograph in a neonate shows no free air or air fluid levels but does show dilated loops of bowel, suggestive of distal bowel obstruction. No calcifications to suggest perforation are seen. PA contrast enema shows a microcolon. Contrast refluxing into the terminal ileum outlines meconium pellets, typical of meconium ileus, seen with distal ileal fillings defects. Contrast could not be refluxed further into the proximal dilated small bowel. Anteroposterior contrast enema shows microcolon with terminal ileum filled with meconium plug and pellets like "pearls on a string", consistent with meconium ileus. Longitudinal ultrasound shows multiple meconium-filled dilated small bowel loops with wall-thickening. Mild ascites is noted. Transverse ultrasound shows a dilated, meconium-filled bowel loop with wall thickening. The constellation of findings is consistent with a complicated meconium ileus, and a superimposed segmental volvulus was found at surgery. Cystic fibrosis testing was positive. Sagittal ultrasound shows a dilated bowel loop in the right abdomen with wall thickening and meconium impaction. Mild ascites is noted. A contrasted enema subsequently showed a microcolon. Necrotic small bowel was surgically resected in this complicated meconium ileus. Surgery is required for simple meconium ileus from CF Complications: Perforation = AP Radiograph: Several calcifications are seen in the right upper quadrant; This patient had an in utero bowel perforation due to meconium ileus in CF. Perforation is likely due to ischemic loop of bowel. Goal of therapeutic enema - prone patient; contrast in the dilated loops proximal to the terminal ileal obstruction	Gastrointestinal Imaging
Meconium Plug Syndrome (cf Muconium Ileus) MPS aka small left colon syndrome	Digital rectal examination must be performed prior to the prior to contrast enema to exclude anorectla malformation.	Gastrointestinal Imaging
Meconium Plug Syndrome (cf Muconium Ileus) MPS aka small left colon syndrome	The patient's mother had diabetes mellitus.  Infant whose mother was treated for preeclampsia with magnesium sulfate. Baby with ?cystic fibrosis; bilious emesis, premature infants AP Radiograph: shows generalized gaseous distention of small bowel loops and proximal colon (though it is often not possible to differenciate small and large bowel in the neonate) with no rectal gas. Ascending and transverse colon filled with meconium. No free air or abnormal calcifications to suggest complication. PA contrast enema shows a normal rectal caliber with decreased size of the sigmoid and descending colon. There is a normal caliber transverse colon. Note the unopacified dilated proximal small bowel loops. Contrast enema may outline a meconium cast, multiple fillings defects are present A normal rectosigmoid ratio, small left colon, and a transition zone to dilated colon at the level of the splenic flexure. PA contrast enema better shows the transition point at the splenic flexure (cf with Hirshprug Disease). The colonic function (motility) recovers following this study, with resoloution of emesis and intestinal obstrction, is typical of meconium plug syndrome. Lateral contrast enema: in a newborn with bilious emesis shows a normal rectal caliber with small sigmoid colon. Shows small left colon with abrupt transition zone to dilated bowel at the splenic flexure.  Meconium is seen in the distal colon. US: dilated small bowel llops; right colon is filled with meconium; alternating normal and reversed peristalsis or abscence of peristalsis. Rectal biopsy showed normal ganglion cells. CT: not required Differential diagnosis: Meconium Ileus: microcolon; obstruction is usually in the terminal ileum; associated with cystic fibrosis Hirschprung disease: typical segmental rectosigmoid stenosis; abrupt change in diameter of the colon with dilated proximal colon Ileal atresia: microcolon; small bowel loops distal to the atresia are narrowed	Gastrointestinal Imaging
Meniscus sign (ERCP, CT)	Extrahepatic biliary dilatation - Lithiasis-related disease	Gastrointestinal Imaging
Moulage sign	Hypersecretion and mucosal atrophy cause the moulage sign (rare). Malabsorption	Gastrointestinal Imaging
Negative Murphy's sign	• Gangrenous cholecystitis: rupture of GB; mortality, 20% gangrene causes nerve death so that 65% of patients have a negative Murphy's sign.	Gastrointestinal Imaging
Neonatal Distal Bowel Obstruction	Findings of contrast enema (CE) limit differential diagnosis: Colonic vs. small bowel process Antenatal or prenatal midgut volvulus late in natural history (ischemia); ileus can mimic distal bowel obstruction Hirschsprung disease more common in patients with Down syndrome Consider meconium ileus if family history of cystic fibrosis Meconium plug syndrome associated with maternal Mg++ therapy, maternal diabetes No rectal opening in male or single perineal opening in female patient with ARM Abdominal radiographs: Many dilated bowel loops ± air-fluid levels If dilated bowel loops but no air-fluid levels, suspect meconium ileus If CE and upper GI (UGI) normal in face of obstruction, consider omphalomesenteric duct remnant anomaly	Gastrointestinal Imaging
Northern exposure sign	Northern exposure sign: dilated twisted sigmoid colon projects above transverse colon Volvulus	Gastrointestinal Imaging
Obliteration of fat around celiac axis or SMA	Extrapancreatic extension • Most commonly retropancreatic (obliteration of fat around celiac axis or SMA one sign of incurability)	Gastrointestinal Imaging
Omega sign	Omega sign: asymmetric wall involvement results in contracture and C-shaped loop on small bowel series Crohn disease (regional enteritis)	Gastrointestinal Imaging
Pancreatitis causes identifiable on CT scan	Gallstone pancreatitis: if gall stones present, look at CBD and ampulla, Autoimmune Pancreatitis: - Chronic inflammatory pancreatitis = mixed inflammatory infiltrate; Rare 2%; Minimal abdominal pain; weight loss, recent-onset DM; Elevated IgG4; Respond to steroids - Diffuse enlargement of the pancreas (rarely focal); diffuse or segmental narrowing of the pancreatic duct; Minimal peripancreatic stranding; Low attenuation capsule like rim - may show delayed enhancement; Strictures of the CBD  - thickening and enhancement - Extrapancreatic findings: retropancreatic findings; retroperitoneal fibrosis; salivary gland enlargement; renal involvement = renal infarcts or discreat renal parenchymal lesions; Lung disease (reticular nodules or ground-glass); mediastinal adenopathy Pancreatic Malignancy No identifiable: alcoholism, hypercholestrolism etc	Gastrointestinal Imaging
Pancreatitis veneous and arterial complications	Veneous thrombosis: - Splenic vein thrombosis: intimal injury secondary to adjacent inflammation; Mass effect and compression of vein - SMV and portal vein thrombosis less common - Look for varices: Omental and gastroepiploic So look at the Central Veins SMV in axial and coronal plains; serching for varicies Psudoaneurysms: Pancreatic enzymes weaken arterial wall; most common sites: - splenic artery 40%; GDA 30%; pancreaticoduodenal arcade 20%; Gastric 5%; Hepatic 2% Arterial phase is critical Mortality is >90% if psudoaneurysm ruptures So use MIP imaging to hunt down the psedoaneurysms	Gastrointestinal Imaging
pearls on a string	Anteroposterior contrast enema shows microcolon with terminal ileum filled with meconium plug and pellets like "pearls on a string", consistent with meconium ileus.	Gastrointestinal Imaging
Peripheral washout sign	Peripheral washout sign (when seen) is characteristic of metastases.	Gastrointestinal Imaging
Positive Murphy's sign	Positive Murphy's sign (sensitivity, 60%; specificity, 90%) Acute cholecystitis Xanthogranulomatous cholecystitis	Gastrointestinal Imaging
Ram's horn sign	Ram's horn sign: loss of antral fornices with progressive narrowing from antrum to pylorus Crohn disease (regional enteritis)	Gastrointestinal Imaging
Ring or halo sign	Thick folds without malabsorption pattern (edema, tumor hemorrhage) (Fig. 3-107, A and B) Criteria: folds >3 mm. By CT, the edema in small bowel wall may appear as ring or halo sign. Two types: • Diffuse: uniformly thickened folds • Focal: nodular thickening (“pinky printing”), analogous to “thumbprinting” in ischemic colitis, stack-of-coins appearance, picket fence appearance. Causes Submucosal edema • Ischemia • Enteritis Infectious Radiation • Hypoproteinemia • Graft-versus-host reaction Submucosal tumor • Lymphoma, leukemia • Infiltrating carcinoid causing venous stasis Submucosal hemorrhage • Henoch-Schönlein disease • Hemolytic-uremic syndrome • Coagulopathies (e.g., hemophilia, vitamin K, anticoagulants) • Thrombocytopenia, disseminated intravascular coagulation Nodules • Mastocytosis • Lymphoid hyperplasia • Lymphoma • Metastases • Polyps • Crohn disease Small Bowel Stack of Coins Appearance • Anticoagulation • Vasculitis • Trauma • Ischemia • Carcinoid Small Bowel Luminal Narrowing • Ischemia • Vasculitis • Hemorrhage • Radiation • Collagen vascular disease • Inflammatory bowel disease • Tumor • Adhesions CT Bowel Target Sign • Ischemia • Vasculitis • Hemorrhage • Inflammatory bowel disease • Angioedema: ACEi, hereditary, allergic reaction • Portal hypertension • NSAIDs Gracile Small Bowel Tubular “toothpaste” appearance on small bowel series • Graft-versus-host disease • Cryptosporidium	Gastrointestinal Imaging
Sentinel clot sign	SPLEEN Blood clot is of high CT density and often located near source of bleeding: sentinel clot sign.	Gastrointestinal Imaging
Small Bowel Imaging	Use 1L as a contrast agent (neutral contrast agent); inexpensive and well tolerated; allows good visulaisation of the enhancing bowel wall; does not interfere with 3D imaging. Disadvantages: empties quickly; not optimal distension of the distal small bowel Evaluation of mesenteric vessels use .75mm, but for abdominal organs use 5mm Arterial and venous phase 120CC of non-ionic contrast, Arteries: Celiac Axis - supplies lower esophagus to the descending duodenum.  Hepatic,splenic and left gastric branches. gastroduodenal artery is usually the first branch of teh common hepatic artery and provides an important collateral pathway between the celiac axis and the SMA SMA: supplies the midgut - 3rd and 4th portions of the duodenum , jejunum, ileum, right colon, transverse colon ro splenic flexure; inportant collateral pathways between the SMA and IMA - Marginal artery of Drummond, Arc of Riolan IMA: supplies colon from the splenic fexure to the rectum - left colic, marginal, sigmoid, superior hemorrhoidals; Important collateral pathways - Lumbar branches to abdominal aorta , sacral artery, and internal iliac arteries Use Saggital projection for evaluating mesenteric vessels; Anatomical varients: Celiac Axis and the SMA arise from a common trunk from the aorta Median arcuate ligament syndrome: inferior crura from the diaphragm is low and causes compression and stenosis of the celiac trunk Veins: Portal vein - superior mesenteric vein and the inferior mesenteric vein (splenic vein )	Gastrointestinal Imaging
Sonographic Murphy's sign	Acalculous cholecystitis on US • No calculi • Sludge and debris • Usually in critically ill patients • Same findings as in calculous cholecystitis: Sonographic Murphy's sign GB wall thickening (>2 mm) Pericholecystic fluid May occur in absence of any of the above findings	Gastrointestinal Imaging
Stierlin sign	Loss of demarcation between cecum and terminal ileum (Stierlin sign); • Narrowed terminal ileum (Stierlin sign) Infectious colitis - Intestinal tuberculosis (TB) Deep Ulceration	Gastrointestinal Imaging
String sign	String sign: tubular narrowing of intestinal lumen (edema, spasm, scarring depending on chronicity) Crohn disease (regional enteritis) Crohn disease: aphthous ulcers → linear fissures → nodules → cobblestone → stricture, spasm (string sign), fistula	Gastrointestinal Imaging
T2 lightbulb sign (lesion has CSF intensity)	T2 lightbulb sign (lesion has CSF intensity) Hemangioma Cysts Cystic metastases Cystadenocarcinoma	Gastrointestinal Imaging
Target sign	Chemotherapy-induced enteropathy appears as nonspecific focal or diffuse bowel wall thickening with or without the target sign or as regional mesenteric vascular engorgement and haziness, more often in distal small bowel. Drug chemotherapy-induced enteritis	Gastrointestinal Imaging
Target sign	Mural and Extramural Changes (CT Findings) • Inner and outer layers surrounding low-attenuation middle layer: target sign; middle layer of fat density; chronic, middle layer of water density Crohn disease (regional enteritis)	Gastrointestinal Imaging
Target Sign	The target sign of thickened bowel wall on contrast-enhanced CT scans of the abdomen consists of three layers that comprise contrast-enhanced inner and outer layers of high attenuation between which a layer of decreased attenuation can be seen. The target sign is seen with various diseases of the bowel in which submucosal edema, inflammation, or both are present. The inner and outer layers of the target sign represent the enhancing mucosa and the muscularis propria, respectively. The low attenuation of the middle layer results from submucosal edema or inflammation Many malignant liver lesions may show a hypoechoic halo—the target sign of a liver lesion (Fig. 10C). The cause of this sonolucent halo is controversial and is nonspecific and can also be seen in hepatocellular carcinoma, adenoma, focal nodular hyperplasia, hemangioma, lymphoma, and fungal microabscesses A reversed target sign with hyperechoic rim due to septal fibrosis and increased vascularity was described in cirrhotic liver nodules. The target sign was also described on ultrasound of metastatic melanoma of the breast	Gastrointestinal Imaging
Torricelli-Bernoulli sign	Crescent-shaped necrosis (Torricelli-Bernoulli sign) in large GIST	Gastrointestinal Imaging
Wall-echo-shadow (WES triad, double-arc sign)	Wall-echo-shadow (WES triad, double-arc sign) is seen if the GB is contracted (type II) and completely filled with stones; however, WES triad can also be seen with: Porcelain GB (calcification of GB) Emphysematous cholecystitis	Gastrointestinal Imaging
Water lily sign	• Water lily sign Echinococcus (hydatid disease)	Gastrointestinal Imaging
Beak sign on IVP	• “Beak sign” can be seen with large cysts seen on IVP	Genitourinary Imaging
Bergman's coiled catheter sign	Bergman's coiled catheter sign: on retrograde pyelogram the catheter is typically coiled in dilated portion of ureter just distal to the lesion.	Genitourinary Imaging
Doughnut sign on IVP or angiography	Lobar dysmorphism: doughnut sign on IVP or angiography	Genitourinary Imaging
Goblet sign	Goblet sign: retrograde pyelogram demonstrates dilated ureteral segment distal to obstruction with filling defect and meniscus Ureteral tumors	Genitourinary Imaging
Pseudokidney sign (US)	Elliptical structure in pelvis or abdomen with an echogenic center (blood, prominent mucosa, infiltrated bowel wall) resembling the US appearance of a kidney. • Inflammatory bowel disease Crohn disease Infectious colitis • Tumor • Intussusception • Always exclude pelvic kidney	Genitourinary Imaging
Ring sign	Sequestered, sloughed papillae cause filling defects in collecting system: “ring sign.” Renal papillary necrosis (RPN)	Genitourinary Imaging
What am I missing on NECT?	Fast scan, specific for renal stones, Not for appendicitis or Kidney: Phlebolith in vascular malformation mimiking the stone; Renal arterial aneurysm seen on coronal and saggital, Renal cell carcinoma; pyelonephritis - bands of decreased enhancement; renal infarct;	Genitourinary Imaging
multiplicity is not a sign of a benign condition	US guidelines for thyroid nodules: • 80% of nodular disease is due to hyperplasia (pathologically they are referred to as hyperplastic, adenomatous, or colloid nodules). • Malignant and benign nodules present simultaneously in 10%-20% of cases; thus multiplicity is not a sign of a benign condition. • Nodules with large cystic components are usually benign; however, 20% of papillary cancers are cystic. • Comet-tail artifacts are seen in colloid cysts.	Head and Neck Imaging
Blood–brain barrier damage	A pathological increase of permeability of the blood–brain barrier occurs in several conditions, e.g. many cerebral and meningeal tumours, cerebral infarcts and in some infections. This is the basis of the very useful diagnostic sign of tumour staining, which is particularly well seen on CT, even after IV injection of contrast medium.	INTRAVASCULAR CONTRAST MEDIA FOR RADIOLOGY, CT AND MRI
Abnormally Large Fontanelles	Abnormally large fontanelles may arise in conjunction with suture spreading from elevated intracranial pressure or as part of skeletal dysplasias, such as osteogenesis imperfecta and cleidocranial dysplasia	Musculoskeletal Imaging
achondroplasia	Achondroplasia is an autosomal dominent anomaly that affects the cartilage growth and development. The individual is a short limbed dwarf with a relatively normal sized trunk, large head, frontal bossing, and a depressed nasal bridge. ULTRASOUND The diagnosis can be made by fetal ultrasound by progressive discordance between the femur length and biparietal diameter by age. The trident hand configuration can be seen if the fingers are fully extended. A skeletal survey is useful to confirm the diagnosis of achondroplasia. SKULL The skull is large, with a small narrow foramen magnum, and relatively small skull base. LIMBS Short wide tubular bones with metaphyseal cupping and flaring and irregular growth plates. Fibular overgrowth is present. The hand is broad with short metacarpals and phalanges, and a trident configuration. ‘Trident hand’: the fingers are all the same length and diverge into 2 pairs ‘Chevron’ deformity: V-shaped growth plate notches THORAX Short ribs with cupped anterior ends. VERTEBRAE A decreasing interpedicular distance within the lumbar spine (travelling caudally) short vertebral pedicles posterior vertebral body scalloping ‘Bullet-shaped’ vertebral bodies: with an anteroinferior anterior beak The vertebral bodies are short and flattened with relatively large intervertebral disk height, and there is congenitally narrowed spinal canal. Thoracolumbar gibbus in infancy. PELVIS ‘Tombstone’ appearance: squared small iliac wings with a small sciatic notch ‘Champagne glass’ pelvis: the pelvic inlet resembles a champagne glass flat acetabular roofs The iliac wings are small and squared,[5] with a narrow sciatic notch and horizontal acetabular roof. If the radiographic features are not classic, a search for a different diagnosis should be entertained. Because of the extremely deformed bone structure, people with achondroplasia are often "double jointed".	Musculoskeletal Imaging
Acrocephalosyndactyly	Acrocephalosyndactyly = syndrome characterized by 1. increased height of skull vault due to generalized craniosynostosis (= acrocephaly, oxycephaly) 2. syndactyly of fingers / toes	Musculoskeletal Imaging
Bayonet deformity (Madelung deformity)	Bayonet deformity (Madelung deformity) is a skeletal deformity of the wrist characterized by an acute angular configuration and palmar displacement of the proximal carpal row It is associated with Turner syndrome (10% of cases) and chondrodysplasia of the distal radial epiphysis, or Leri-Layani-Weill syndrome (dyschondrosteosis).	Musculoskeletal Imaging
Bayonet fracture	Bayonet fracture is a configuration characterized by overlapping of fracture surfaces with resultant shortening	Musculoskeletal Imaging
bone marrow edema	Earliest sign of osteonecrosis is bone marrow edema (nonspecific)	Musculoskeletal Imaging
brachycephaly in osteogenesis imperfecta	Premature fusion of the coronal suture restricts anteroposterior skull growth and is followed by compensatory overgrowth of the sagittal suture laterally and lambdoid sutures caudally. The resultant skull deformity is referred to as brachycephaly (12) (Fig 2). The frontal fontanel is wider and remains open longer than normal	Musculoskeletal Imaging
Bullet vertebra	Bullet vertebra indicates anterior beaks of the vertebral body and is seen in mucopolysaccharidosis (Morquio disease, Hurler disease) and achondroplasia	Musculoskeletal Imaging
Cannonball	Cannonball metastases are one or more large, well-circumscribed metastatic nodules in the lungs that are classically seen in renal cell carcinoma but also can be seen in choriocarcinoma	Musculoskeletal Imaging
cartilage interface sign	Shoulder ultrasound. Full-thickness tear: focal tendon defect/fluid; concave contour of bursal side of tendon; compressible tendon; cartilage interface sign (two parallel hyperechoic lines over humeral head)	Musculoskeletal Imaging
Causes of Scalloping in Vertebral Bodies	Increased Intraspinal Pressure Intradural neoplasmsIntraspinal cysts Syringomyelia and hydromyelia Communicating hydrocephalus Dural Ectasia Marfan syndrome Ehlers-Danlos syndrome Neurofi bromatosis Bone Resorption Acromegaly Congenital Disorders Achondroplasia Morquio disease Hunter syndrome Osteogenesis imperfecta (tarda) Physiologic Scalloping	Musculoskeletal Imaging
Cleft Palate (25%)	lack of fusion of mesenchymal masses of lateral palatine processes around 8th and 9th weeks MA Associated with: anomalies in 50% (most frequently clubfoot + polydactyly)	Musculoskeletal Imaging
Cleidocranial Dysplasia	Cleidocranial dysplasia is an autosomal dominant syndrome affecting membranous bone. The locus for this dysplasia has been isolated to the short arm of chromosome 6. The abnormalities are caused by mutations in the CBFA1 gene, a transcription factor that activates osteoblastic differentiation (42). Cleidocranial dysplasia is characterized by widening of the fontanelles with broad lateral cranial diameter and multiple wormian bones along the lambdoid suture (Fig 14). The sutures and fontanelles close late. Associated skeletal anomalies include absent or hypoplastic clavicles, a widened pubic symphysis, multiple spinal anomalies, and hypoplastic middle and distal phalanges. Hearing loss occurs in 38% of those affected with cleidocranial dysplasia Anterior fontanelle has remained widely patent. Frontal (a) and lateral (b) skull radiographs show frontal bossing, brachycephaly, wide biparietal diameter, and wormian bones along the lambdoid sutures. Concomitant ossicular abnormalities required use of a hearing aid.	Musculoskeletal Imaging
Complications of a fracture	Mal-union: failure to position a fracture correctly can result in abnormal alignment or mal-union, which may be unacceptable clinically. Delayed union: seek any systemic condition that may co-exist Non-union may result from: Poor alignment of the original fracture, with considerable seperation between the bone ends; A reactive sclerosis, with poor joining qualities; Ischemic necrosis; or Infection Diffuse osteoporosis: results from bone imobilisation by plaster casts. A severe form, Sudeck's atrophy, is accompanied by pain, soft tissue swelling and skin chnages.  Soft tissue damage: extensive traumatic damage may result in myositis ossificans. If blood vessel damage occurs, distal ischemic (Volkmann) contracture may result. ISchemic necrosis: Femoral head after subcapital fracture The humeral head The Scaphoid The changes in the ischemic bone, which may later collapse and fragment, detected on MR	Musculoskeletal Imaging
Corner Sign	• Corner sign: metaphyseal fractures (Pelkan spurs)	Musculoskeletal Imaging
crescent sign	OsteoneCrosis Stage III Plain film staging system (Ficat): translucent subcortical fracture line (crescent sign), flattening of femoral head	Musculoskeletal Imaging
Dagger	Dagger has double-edged blade used for stabbing or thrusting The dagger sign is a single central radiodense line on frontal radiographs related to ossification of supraspinous and interspinous ligaments. Bony fusion of the adjacent lumbar vertebrae with syndesmophyte formation is characteristic for ankylosing spondylitis. In addition, there is a linear increased density running along the spinous processes	Musculoskeletal Imaging
Dagger sign, trolley track sign	Dagger sign, trolley track sign: one or three dense lines along spine due to ossification of interspinous and supraspinous ligaments.	Musculoskeletal Imaging
Double posterior cruciate ligament (PCL) sign and flipped meniscus sign	Bucket-handle: may become displaced or detached. There are characteristic signs by MRI: double posterior cruciate ligament (PCL) sign and flipped meniscus sign. The displaced fragment is typically seen within the intercondylar notch.	Musculoskeletal Imaging
double-barrel sign	The double-barrel sign of simultaneous imaging of a portal vein branch and a second parallel tubular structure has been reported to be a highly accurate sign for intrahepatic biliary duct dilatation. Two parallel tubular structures may be identified within the substance of the liver in patients without intrahepatic bile duct dilatation when hepatic arteries are enlarged because of increased blood flow Sonogram shows double-barrel sign, which is simultaneous imaging of portal vein branch and parallel dilated intrahepatic biliary duct	Musculoskeletal Imaging
Fallen fragment sign	Fallen fragment sign secondary to pathologic fracture is pathognomonic for UBC: fragment migrates to dependent portion of cyst.	Musculoskeletal Imaging
Fat (marrow)-fluid (blood) interface sign (hemarthrosis) on cross-table lateral view	Fracture of the proximal tibia Fat (marrow)-fluid (blood) interface sign (hemarthrosis) on cross-table lateral view	Musculoskeletal Imaging
Ghost sign	AP view: ghost sign (double-spinous process on C6-C7 caused by caudal displacement of the fractured tip of the spinous  process) Clay-shoveler's fracture	Musculoskeletal Imaging
Hip dysplasias	Congenital dislocation of the hip: Girls, bilateral 25%. Acetabular dysplasia: increased acetabular angle, delayed femoral capital epiphysis, and lateral subluxation of the hip. Subluxation can pe partial. Look for dislocation contralaterally. Perthes' disease. Osteonecrosis of the proximal femoral capital epiphysis in Pethes disease may occur around the age of 6 years, boys, may be bilateral. Ischemic necrosis as a result of minor trauma to the blood supply. Deformity of the femoral head with premature osteoarthritis. Abnormality of the epipyseal plate and associated metaphysis.  Note the increased joint space. SUFE - Slipped upper femoral epiphysis: adolacent boys, ?related to growth spurts. Caused by posterior slip of the femoral capital epiphysis, 30% bilateral. The abnormal angulation of the femoral head in realtion to the femoral neck indicates a posterior slip.	Musculoskeletal Imaging
Hole-within-a-hole sign	• Beveled-edge appearance may produce hole-within-a-hole sign (outer table is more destroyed than inner table; button sequestrum); best seen by CT. Eosinophilic granuloma (EG) Langerhans cell histiocytosis	Musculoskeletal Imaging
lower-extremity bowing in children	lower-extremity bowing in children, including developmental bowing, congenital bowing, tibia vara (Blount disease) (Figs 1, 2), neurofibromatosis, osteogenesis imperfecta, rickets, camptomelic dysplasia, and achondroplasia	Musculoskeletal Imaging
Madelung's deformity	Madelung's deformity: characteristic of premature fusion of the distal radius, with subsequent developmental abnormailites of the ulna and wrist (proximal carpal bones).	Musculoskeletal Imaging
Mitten” polysyndactyly of soft tissues and bones	Apert’s syndrome	Musculoskeletal Imaging
Morquio Syndrome MUCOPOLYSACCHARIDOSES (MORQUIO, HURLER, AND HUNTER SYNDROMES)	Morquio Syndrome.   A lateral plain film of the spine reveals a central beak or anterior bony projection off the vertebral bodies in this patient with Morquio syndrome. Hurler Syndrome.   A lateral plain film of the spine in this patient with Hurler syndrome shows an inferiorly placed bony projection extending anteriorly off the vertebral bodies Hurler Syndrome.   An anteroposterior plain film of the hand in this patient with Hurler syndrome shows a notch at the base of the fifth metacarpal, which is a characteristic finding in all of the mucopolysaccharidoses.	Musculoskeletal Imaging
Mucopolysaccharidoses	Secondary to specific enzyme deficiencies Morquio-Brailsford syndrome Hurler syndrome or gargoylism: abnormal hook shaped vertebral body, fatal within the first 10 years. Abnormal trabecular pattern throughout the bones of the hand can also be seen.	Musculoskeletal Imaging
Myositis Ossificans Progressiva	Myositis Ossificans Progressiva: rare, AD, formation of bone throughout muscle planes, ligaments, and soft tissue. The disease progresses from the upper thoracic spine, downwards and outwards, resulting inextensisve formation of bone around the thorax. The person dies of respiratory failure before reaching adulthood. No effective treatment of this condition. Fixation of the thoracic chage by extraosseous bone formation.	Musculoskeletal Imaging
Neurofibromatosis	AD Skeletal changes 50% Pseudoarthroses, bowing deformaties, kyphoscoliosis with bowing of the posterior vertebral bodies Lateral cervical spine: abnormal development of the cervical spine, posterior scalloping of the vertebral bodies CXR: large neurofibroma in the apex	Musculoskeletal Imaging
Osteonecrosis	• Early AVN: focal subchondral abnormalities (very specific) Dark band on T1W/bright band on T2W Double-line sign (T2W): bright inner band/dark outer band occurs later in disease process after the start of osseous repair • Late AVN: fibrosis of subchondral bone Dark on T1W and T2W images Femoral head collapse • Mitchell classification Class A (early disease): signal intensity analogous to fat (high on T1W and intermediate on T2W) Class B: signal intensity analogous to blood (high on T1W and T2W) Class C: signal intensity analogous to fluid (low on T1W and high on T2W) Class D (late disease): signal intensity analogous to fibrous tissue (low on T1W and T2W)	Musculoskeletal Imaging
Patella baja (low patella)	Patella baja (low patella): this is associated with polio, juvenile chronic arthritis and achondroplasia	Musculoskeletal Imaging
Patellar tooth sign	Patellar tooth sign (enthesopathy at the patellar attachment of the quadriceps tendon)	Musculoskeletal Imaging
Pistol-grip deformity	MR image of pistol-grip deformity, which is abnormal flattening or convexity of usually concave femoral head–neck junction that causes cam type of femoroacetabular impingement secondary to a nonspherical femoral head impinging within the acetabulum It may be developmental or posttraumatic (e.g., as a result of slipped capital femoral epiphysis). With hip flexion, the nonspherical portion of the femoral neck impinges on the anterosuperior portion of the acetabulum. This causes primarily chondral injuries and leads to associated labral detachment	Musculoskeletal Imaging
Platyspondyly generalisata Generalized Platyspondyly (Decreased Height of Vertebral Body)	Platyspondyly: flattened vertebral bodies associated with many hereditary systemic disorders (achondroplasia, spondyloepiphyseal dysplasia tarda, mucopolysaccharidosis, osteopetrosis, neurofibromatosis, osteogenesis imperfecta, thanatophoric dwarfism) disk spaces of normal height • Osteogenesis imperfecta • Dwarfism (thanatophoric, metatropic) • Morquio syndrome • Cushing syndrome	Musculoskeletal Imaging
polydactyly	Associations: Bardet-Biedl syndrome, HIRSCHSPRUNG’S DISEASE, ELLIS–VAN CREVELD (CHONDROECTODERMAL DYSPLASIA) (GROUP 4), Frequently associated with: 1. Carpenter syndrome 2. Ellis-van Creveld syndrome 3. Meckel-Gruber syndrome 4. Polysyndactyly syndrome 5. Short rib-polydactyly syndrome 6. Trisomy 13 7. ASPHYXIATING THORACIC DYSPLASIA (JEUNE’S) (GROUP 4), 8. Smith-Lemli-Opitz syndrome Cleft Palate	Musculoskeletal Imaging
Positive Fat Pad Sign and Sail sign	• Positive fat pad sign Anterior fat pad has the appearance of a sail (sail sign). A positive posterior fat pad is a good indicator of a fracture that is not normally seen. Radial head fractures	Musculoskeletal Imaging
Prevertebral soft tissue swelling	Prevertebral soft tissue swelling (may be the only sign) Fractures of the odontoid process (dens)	Musculoskeletal Imaging
rifle-barrel sign	Radiographs show rifle-barrel sign in pure posterior dislocation of shoulder, which can be recognized on frontal radiographs on basis of appearance of severely internally rotated humeral head described as resembling rifle barrel. In fact, it resembles smoothbore barrel because no rifling is seen on appearance of severely internally rotated humeral head. The rifle-barrel sign is radiographic recognition of the pure posterior dislocation of the shoulder on frontal radiographs on the basis of the appearance of the severely internally rotated humeral head described as resembling a rifle barrel [17]. Posterior shoulder dislocation is rare and reported to be unrecognized in as many as 50% of cases on radiographs. The relationship of the humeral head to the glenoid may appear normal on frontal radiographs of the shoulder. Radiographic recognition of the rare pure posterior dislocation of the shoulder on frontal radiographs Posterior shoulder dislocation is rare and reported to be unrecognized in as many as 50% of cases on radiographs. The relationship of the humeral head to the glenoid may appear normal on frontal radiographs of the shoulder. Radiographic recognition of the rare pure posterior dislocation of the shoulder on frontal radiographs depends on the appearance of a rifle-barrel sign. However, the rifle-barrel sign is in fact a misnomer. On Figure 7, smooth-bore and rifled barrels are shown. No rifling is seen on the appearance of the severely internally rotated humeral head	Musculoskeletal Imaging
Saber-sheath trachea	Saber-sheath trachea indicates a trachea in which an increase is found in the outer posterior tracheal dimension with side-to-side narrowing involving the intrathoracic trachea (Fig. 8B). The coronal dimension is less than or equal to two thirds of the sagittal dimension. Usually, the extrathoracic trachea is normal. The cause for this shape could be secondary to expanded lung volume of upper lobes seen in patients with obstructive lung disease, which greatly restricts the potential side-to-side dimensions of the paratracheal mediastinum. This forces the trachea to remodel itself into a saber-sheath configuration in some patients with chronic obstructive pulmonary disease. This sign could also be secondary to deformity of tracheal cartilage or chronic injury. The saber-sheath trachea can simulate a mediastinal mass	Musculoskeletal Imaging
Scimitar	Scimitar is slicing weapon with blade, modeled on lion’s claw. Distinctive curved blade ending with sharp point was capable of cutting off limbs or head of enemy in one stroke. Coronal reformatted CT shows scimitar syndrome, which is anomalous venous return from right lung with pulmonary veins draining to inferior vena cava and creating curvilinear density that has the shape of a scimitar on a chest radiograph. This anomalous pulmonary venous return can be either partial or total.	Musculoskeletal Imaging
Sclerotic Bone diseases	Osteopetrosis (marble bone disease): Excessive increase in cortical bone thickness, reduction in the size of the medulla  and widespread sclerosis. Bone modelling deformaties. Osteopoikilosis: areas of sclerotic bone oftern seen around large joints, asymptomatic, diagnosed incidentally. Hand: widespread sclerotic, punctate areas of bone adjacent to joints are characteristic.	Musculoskeletal Imaging
Sedimentation sign	CT may reveal cystic spaces with fluidfluid levels (sedimentation sign). Tumoral Calcinosis	Musculoskeletal Imaging
Shiny corners:	Shiny corners: sclerosis at edges of endplates Ankylosing spondylitis (as)	Musculoskeletal Imaging
Shoulder pad sign	Bulky soft tissue nodules (i.e., shoulder pad sign) Amyloid arthropathy	Musculoskeletal Imaging
Spina Bifida	Spina Bifida failure of fusion of the posterior elements of the vertebral column. There is widening of the interpedicular distance. Neurological abnormality may result in abnormal development of the pelvis and lower limbs.	Musculoskeletal Imaging
Spinal Stenosis	Spinal stenosis is defined as bony and soft tissue structures encroaching upon neural elements with resulting symptoms  Central Canal Stenosis. Simply noting whether the thecal sac is compressed or round will reliably determine central canal stenosis. Is it mild moderate or severe? Facet Hypertrophy Degenerative disease Facet Hypertrophy Ligment Flavum Hypertrophy on T2W Uncommon causes: bony overgrowth from Paget disease, achondroplasia, posttraumatic changes, and severe spondylolisthesis Neuroforaminal  Stenosis DJD of the facet with bony hypertrophy Less common: free disc fragments, postoperative scar, and from a lateral disc protrusion. Lateral recess  Stenosis Hypertrophy of the superior articular facet from DJD Other: disc fragments and post-operative scar can cause nerve root impingement. Facet Hypertrophy	Musculoskeletal Imaging
Spinous process sign	Pseudospondylolisthesis (Fig. 5-22) Secondary to degenerative disk disease and/or apophyseal degenerative joint disease. Use spinous process sign to differentiate from true spondylolisthesis. In true spondylolisthesis, the spinous process stepoff is above the level of vertebral slip; whereas in pseudospondylolisthesis, the stepoff is below the level of the slip.	Musculoskeletal Imaging
Syndactyly	Preaxial and postaxial polysyndactyly Apert syndrome, triploidy, Roberts syndrome Ipsilateral: Poland syndrome associated with ipsilateral syndactyly  ‘Mitten’ or ‘sock’ deformities: these are due to syndactyly (fused digits) of the hands and feet seen in DYSOTOSES (LOCALIZED DISORDERS WITH PREDOMINANT CRANIAL AND FACIAL INVOLVEMENT) Syndactyly = osseous ± cutaneous fusion of digits 1. Apert syndrome 2. Carpenter syndrome 3. Down syndrome 4. Neurofibromatosis 5. Poland syndrome 6. Others • Constriction band syndrome	Musculoskeletal Imaging
Terry-Thomas sign and Ring sign	Scapholunate Dissociation (Stage 1) • Rupture of scaphoid ligaments • >3-mm gap between lunate and scaphoid (Terry-Thomas sign) • Ring sign on PA view secondary to rotary subluxation of scaphoid	Musculoskeletal Imaging
Thanatophoric dwarfism ‘Telephone handle’ appearance of the long bones: this is due to metaphyseal flaring § ‘Cloverleaf skull’: this is due to lateral temporal bulging	Thanatophoric dwarfism  is the most common lethal skeletal dysplasia. Distinguishing features include small thorax, cloverleaf skull, large head, hydrocephalus, and polyhydramnios.  Short ribs with wide costochondral junctions ▶ severe platyspondyly ▶ horizontal acetabular roofs with medial spikes ▶ small sacroiliac notches ▶ marked shortness and bowing of the long bones ▶ irregular metaphyses ▶ short broad tubular bones in the hands and feet ▶ small scapulae	Musculoskeletal Imaging
Trap door sign	Displacement of bone fragments into maxillary sinus (trap door sign) Pure Orbital Blow-out Fracture	Musculoskeletal Imaging
Trident deformity	Trident deformity was described initially in achondroplastic dwarfism and in various chondrodysplasias. It is classically described as the second, third, and fourth fingers having the same length and third and fourth fingers that cannot be approximated. The resultant separation between the middle and ring fingers provides the trident appearance of the hand. The fourth and fifth fingers are parallel to each other. The hand is broad with short metacarpals and phalanges, and a trident configuration. Sometimes the trident deformity is described as the four last fingers having the same length and thus including the fifth finger in the abnormality. In this case the term “trident” is incorrect because trident implies the involvement of only three fingers. However, this description is almost universally used today in numerous publications. Trident acetabulum in asphyxiating thoracic dysplasia (Jeune syndrome) is seen as flat acetabular roofs with downward spikelike projections at the medial, lateral, and, sometimes, central aspects of the roofs	Musculoskeletal Imaging
Trough sign	Trough sign (posterior dislocation) Linear impaction fracture of anterior humeral head • Trough sign: compression fracture of the anterior humeral surface, 15% (best seen on AP view with external rotation or axillary view)	Musculoskeletal Imaging
tumbling-bullet sign	The appearance of a tumbling-bullet sign, a bullet falling freely within a fluid-filled posttraumatic bone lesion, indicates a unicameral bone cyst nature of the lesion. This is due to the same principle as a more frequently seen falling fragment sign in which a heavier object is able to move freely in a lighter environment.	Musculoskeletal Imaging
Types of fracture	Comminuted: multiple bones are found at the fracture site Open (compound): a penetrating fracture, in which bone Is exposed to the air. Closed (simple): a fracture contained in the soft tissue Greenstick: only one side of the cortex is involved in the fracture; this type is common in children. Varus deformity: the proximal bone points laterally, with the distal fragment pointing medially (bow legged) Valgus deformity: the proximal bone points medially and the distal fragment points laterally (knocked-knee). Salter-Harris classification: refers to the fracture of long bones of children, in which the fracture involves the metaphysis, the epiphysis, and the epiphyseal line or growth plate. Premature fusion is a common complication of such fractures.	Musculoskeletal Imaging
Ultrasound or MR (yo-yo sign)	Stener's lesion Occurs in a subset of patients with gamekeeper's thumb, when the ulnar collateral ligament is completely torn and displaced superficial and proximal to the adductor pollicis aponeurosis, preventing the UCL from returning to its  normal position. Detect with ultrasound or MR (yo-yo sign). Surgical lesion.	Musculoskeletal Imaging
Wimberger's sign	Wimberger's sign: dense epiphyseal rim Wimberger's ring sign: circular, opaque radiologic shadow surrounding epiphyseal centers of ossification, which may result from bleeding Scurvy Deficiency of vitamin C (ascorbic acid) impairs the ability of connective tissue to produce collagen. Never occurs before 6 months of age because maternal stores are transmitted to fetus. Findings are most evident at sites of rapid bone growth (long bones). Rare. Radiographic Features (Fig. 5-137) Children • Generalized osteopenia • Dense metaphyseal line (Frankel) • Wimberger's sign: dense epiphyseal rim • Corner sign: metaphyseal fractures (Pelkan spurs) • Periosteal reaction (ossification) due to subperiosteal bleeding • Hemarthrosis: bleeding into joint Adults • Osteopenia and pathologic fractures Frankel's line: dense zone of provisional calcification Trümmerfeld zone : lucent metaphyseal band underlying Frankel's line Pelkan spur: metaphyseal spurs which result in cupping of the metaphysis	Musculoskeletal Imaging
Wiskering	irregular bone growth at sites of tendinous insertions; ethesophytes, seen in DJD, DISH, and spondyloarthropathies	Musculoskeletal Imaging
Y Sign	characteristic shape of thecal sac compression in lumbar epidural lipomatosis producing a stellate shape like a "Y"	Musculoskeletal Imaging
atherosCLerotiC disease	Color Doppler flow imaging of carotid arteries • High-grade stenosis with minimal flow (string sign in angiography) is detected more reliably than with conventional Doppler US. CT • To determine complete occlusion versus a string sign (near but not complete occlusion), delayed images must be obtained immediately after the initial contrast images.	Neurologic Imaging
atherosCLerotiC disease	Slim sign: collapse of ICA above stenosis atherosCLerotiC disease	Neurologic Imaging
Bifid post-CS sign (85%)	Bifid post-CS sign (85%)	Neurologic Imaging
cap sign	• T2W: hyperintense. 20%-33% of ependymomas demonstrate the “cap sign,” a rim of extreme hypointensity (hemosiderin) seen at the poles of the tumor on T2W images. Most cases (60%) also show evidence of cord edema around the masses.	Neurologic Imaging
Classification of Plain Radiographic Abnormalities of the Infant Skull	Variations in skull density Decreased density: generalized or localized Increased density: generalized or localized Variations in skull size Decreased size (microcephaly) Increased size (macrocephaly) Abnormal head shape Calvarial defects Acquired conditions Posttraumatic abnormalities Neoplasia	Neurologic Imaging
Craniocervical Junction Abnormalities in osteogenesis imperfecta	Platybasia, basilar impression, and basilar invagination may occur because of bone softening in patients with osteogenesis imperfecta. These three characteristics are distinct, and, despite their frequent coincidence, they should be differentiated when clinically assessing the craniocervical junction	Neurologic Imaging
CT Brain Protocol	Axial CT Brain and bone windows, Iodinated contrast Views, Perfusion CT and CTA may suppliment stroke protocols	Neurologic Imaging
CT vs MR Brain	As a rule if the problem is acute (<48 -="" 48="" adults="" aggitated="" and="" assisted="" br="" cant="" children="" choose="" ct="" highly="" hold="" hours="" if="" in="" is="" mr.="" multisystem="" older="" patients="" problem="" requiring="" start="" still="" that="" the="" then="" trauma="" ventilation="" with=""> If CT or MR fail to demonstrate a stroke - do a corotid doppler US, or MRA or CTA Use NASCET method to diagnose stenosis	Neurologic Imaging
delta sign	Primary (sinus occlusion) • Clot in sinus is hyperdense on noncontrast CT and hypodense on contrast-enhanced CT. • Dural enhancement of sinus margin: delta sign • MRI Bright sinus on T1W and T2W (depending on stage) Absence of flow void • Pearl: If bilateral thalamic infarcts or infarcts do not conform to an arterial territory, suspect venous thrombosis. venous sinus thrombosis	Neurologic Imaging
dense MCA sign	Early CT signs of cerebral infarction include: Loss of gray-white interfaces (insular ribbon sign) Sulcal effacement Hyperdense clot in artery on noncontrast CT (dense MCA sign)	Neurologic Imaging
Diffuse Tensor Imaging	Within elongated cell processes (axons), water can diffuse more freely "down the tube" then sideways; allows for tractography	Neurologic Imaging
Diffusion Weighted Imaging and ADC mapping	Measures fluid restriction as bright lesions, measures ischemia following stroke, CSF is dark as it has the least fluid restriction - Low signal on DWI therefore distinguishes arachnoid cysts from intracranial epidermoid cysts that demonstrate restricted diffusion Restricted diffusion: Multiple Sclerosis, and other demyelinating processes, brain abscess and high cellular  higher-grade primary brain tumors, metastatic disease and lymphoma.	Neurologic Imaging
Emergency CT Brain Checklist:	Midline central; Symmetry of the hemispheres; Smile of the quadrigeminal cistern and the suprasellar cistern Fourth ventrical in the midline and is symmetrical; Enlargement of the lateral ventricles and effacement of the sulci? Signs of Ischemia or hemorrhage of the basal ganglia and the cortex Document NINDS thrombolysis criteria: mass, bleed, and acute infarct Midline structures: - Sella and suprasellar region: localise the sella turcica, pituitary gland, pituitary infundibulum, optic chiasm, anterior third of the ventricle, mammary bodies, and anterior interhemispheric fissure. Tip of the basilar artery and the posterior cerebral arteries seen posteriorly. The anterior cerebral arteries are anterior and superior to the sella. The anterior cerebral arteries travel in the interhemispheric fissure, Parallel to the course of the posterior communicating artery we see the third cranial nerve. Parasagittal section - near optic chiasm, see the optic nerve anteriorly and optic tract posteriorly - the penial region: Must ID the midbrain, midbrain tegmentum, the aquiduct of Sylvius, midbrain tectum, or quadrieminal plate with superior and inferior colliculi, the pineal gland, and the superior cerebellar vermian lobules. If the precentral cerebellar vein can be seen in the superior cerebellar vermian cistern, a mass here is unlikely. - Craniocervical junction: Anterior - arch of C1, Dens, Cervical occipital ligaments, Clivus; Inferior edge of the Clivus marks anterior lip of Foramen Magnum; Cortical margin of occipital bone marks posterior lip of Foramen Magnum; Cerebellar tonsils - project no greater then 5mm below the lips of the foramen magnum, Obex: most posterior projection of the dorsal medulla, lies above imaginary line defining the foramen magnum	Neurologic Imaging
empty thecal sac sign	• Clumping of nerve roots within the thecal sac (intrathecal pseudomass); blunting of caudal nerve root sleeves; nerve roots may also clump peripherally (empty thecal sac sign)	Neurologic Imaging
eye of tiger sign	Hallervorden-Spatz disease (eye of tiger sign — gliosis (white) surrounded by iron deposit (black) on T2W images) t2w hyperintense basaL gangLia Lesions	Neurologic Imaging
Functional MR Brain	BOLD: blood oxygen level-dependent imaging Neuronal activation increases local blood flow; oxyhemoglobin content in exces of tissue requirements Local increase in oxy- to deoxyhemoglobin ratio generates changes in magnetic susceptibility measurable on FMRI Compares images captured during sensory stimulation, motor activity or higher cortical tasks to resting actvity Reliable localisation of motor and language functions assists in  planning surgery for epilepsy and brain tumors Research field	Neurologic Imaging
Hot cross bun sign	• “Hot cross bun” sign in the pons on axial T2/FLAIR parkinson pLus syndromes (patients who respond poorLy to antiparkinson's mediCation) Multisystem Atrophy (MSA)	Neurologic Imaging
Hummingbird sign	Volume loss of the midbrain — Hummingbird sign Progressive Supranuclear Palsy (PSP)	Neurologic Imaging
Insular ribbon sign	Early CT signs of cerebral infarction include: Loss of gray-white interfaces (insular ribbon sign) Sulcal effacement Hyperdense clot in artery on noncontrast CT (dense MCA sign)	Neurologic Imaging
Intraparietal sulcus intersects the post-CS (99%)	Intraparietal sulcus intersects the post-CS (99%)	Neurologic Imaging
Ivy sign	• MRI: multiple tiny flow voids on T2W images, which are collaterals; engorged collaterals may produce FLAIR bright sulci (Ivy sign)	Neurologic Imaging
large lipid peak	• Sign suggesting metastasis over primary brain tumor: large lipid peak	Neurologic Imaging
Leptomeninges insinuate into cerebral sulci	Leptomeninges insinuate into cerebral sulci, which is a sign that helps distinguish a leptomeningeal process from a dural one. Carcinomatous meningitis Leptomeningeal metastases are more common than dural metastases, although the two may coexist. • Common primary neoplasms that cause carcinomatous meningitis include breast, lung, and skin (melanoma). • MRI is more sensitive than CT for detection. • Leptomeninges insinuate into cerebral sulci, which is a sign that helps distinguish a leptomeningeal process from a dural one. • Subarachnoid tumor may be detected early by careful examination of cisternal segment of CN V and intracanalicular segment of CNs VII and VIII	Neurologic Imaging
Macrocephaly	Hydrocephalus Subdural fluid collection Neurofibromatosis Achondroplasia Tuberous sclerosis Metabolic storage disease Alexander disease, Canavan disease Sotos syndrome	neurologic Imaging
Mickey Mouse ears”	Ballooning of temporal horns (“Mickey Mouse ears”) is a sensitive sign. nOnCOmmuniCating hyDrOCephaluS	Neurologic Imaging
Microcephaly	Causes of Microcephaly Severe hypoxic-ischemic injury Trisomy 21 Trisomy 13 Fetal alcohol syndrome TORCH* syndrome Rubinstein-Taybi syndrome Seckel dwarfism	Neurologic Imaging
Midline sulcus sign (70%)	Midline sulcus sign (70%) • Most prominent convexity sulcus that reaches the midline is the CS.	Neurologic Imaging
MR and CT perfusion techniques	Used to depict areas of relatively diminished flow in ischemic cerebral tissue and perfusion. Delayed arrival and transit of contrast on documented ischemia, may predict infarct MR perfusion scans show areas of neovacularisation - high grade tumors	Neurologic Imaging
MR Brain	Fifth cranial nerve: Cisternal segment of the fifth cranial nerve	Neurologic Imaging
MR Brain	Fourth Ventricle Axial and Coronal: Asymmetry or shift in the fourth venticle may be the only sign of significant intracranial mass Some asymmetry in appearance may reflect the patients position in the scanner	Neurologic Imaging
MR Brain	Frontral lobes Coronal NECT MR used as screening examination in chronic dementia for treatable abnormalities: - Large frontal masses; hydrocephlus; small-vessel ischemic changes/infarcts	Neurologic Imaging
MR Brain	Internal auditory canals - cisternal segments of the seventh and eigth crainial nerves	Neurologic Imaging
MR Brain	Level of Cerebral hemispheres, body of the lateral ventricles, internal cerebral veins, foram na of Monro, third ventricle Midline of the brain should be in the middle of the head Symmetry: Two sides should look alike: funtional asymmetries play no role Any shift is presumed to represent a mass lesion Interventricular septum and third ventricle are in the midline, no subfalcine herniation is present Care needs to be taken in evaluating the periphery of the brain for subdural and epidural hematoma Basal Cisterns: - Quadrigeminal plate cistern - symmetrical smile - No rotation of the brainstem in suspected transtentorial hernia, no cerebellar or brainstem mass, no opacification by subarachnoid hemorrhage - Suprasellar cistern: Asymmetry - - uncal herniation Central mass - result from sellar or suprasellar tumor Opacification - subarachnoid hemorrhage Ventricles: fourth ventricle, size, symmetry, - exlude hydrocephalus,	Neurologic Imaging
MR Brain	Level of Suprasellar Cisterns Suprasellar cistern looks like a pentagon, Star of David or the Hindu Shatkona; five corners of the pentagon are - interhemispheric fissure anteriorly, sylvian cisterns anteriolaterally, ambient cisterns posteriorlaterally; the sixth point of the Star of David is the interpeduncular fossa posteriorly	Neurologic Imaging
MR Brain	Midbrain Level Most reliable sign of an extra-axial mass in the posterior fossa is widening of the ipsilateral subarachnoid space: Cerebellum and brainstem displaced away from the bony margins of the calvarium by mass; in contrast, intra-axial masses demonstrate a narrow ipsilateral subarachnoid space. Only structures visible at craniocervical junction within the calvarium and spinal canal are the cervical medullary junction and the cerebellar tonsil. Any other soft tissue at this level is pathalogical.	Neurologic Imaging
MR Brain	Middle Cerevbellar peduncle Coronal: Chronic seizure disorders, refractory to medical therapy; Knowledge of EEG helps	Neurologic Imaging
MR Brain	Optic horns of the lateral venticles: Precentral cerebellar vein in the Superior Vermian Cistern; if visualised a mass here is unlikely	Neurologic Imaging
MR Brain	Optic tracts Coronal: Localise the Sella Turcica; Pituitary gland; Pituitary infundibulum; Optic tracts; Third ventricle; Mammillary body; interhemispheric fissure	Neurologic Imaging
MR Brain	Pituitary gland: Suprasellar cistern in the coronal plane - CSF space; traversed by pituitary infundibulum; deliminated superiorly by optic chiasm, optic tracts; inferiorly by pituitary gland centrally and the cavernous sinuses laterally; laterally by the mesial temporal lobes	Neurologic Imaging
MR Brain	Pituitary infundibulum sagittal: Midbrain; tegmentum of the midbrain; aquiduct of sylvius; Tectum of midbrain - Quadrigeminal plate with superiot and inferior colloculi; Pineal gland; Superior cerebellar vermian lobes; Precentral cerebellar vein in superior vermian cistern - if visualised a mass is unlikely here	Neurologic Imaging
MR Brain	Sagittal midline structures: - asses midline cerebral structures: corpus callosum; pituitary gland; Brainstem; cerebellar vermis	Neurologic Imaging
MR Brain	Third Ventricle: Specific features of AD exist, focal atrophy of the hippocampal regions of the medial temporal lobe	Neurologic Imaging
MR Brain Protocol	T1W, T2W, DWI, FLAIR, T1W+Gad. Susceptability Weighted Imaging may also be obtained.	Neurologic Imaging
MRA string sign	Arterial dissection • CTA is preferred first study of choice—see intimal flap and caliber change • MRI/MRA can also be performed. T1W bright hematoma in vessel wall (sequence: T1W with fat saturation): must be interpreted in conjunction with MRA MRA string sign	Neurologic Imaging
Neptune's trident sign	Trigeminal artery: cavernous ICA to basilar artery (most common), Neptune's trident sign on angiography	Neurologic Imaging
Neuroparenchymal Involvement in osteogenesis imperfecta	Intracranial hemorrhages are attributed to the development of moyamoya disease with subsequent subarachnoid hemorrhage as well as to vertebral artery damage, vascular fragility, spontaneous intracranial hypotension, and friction between multiple bone fragments in the skull	Neurologic Imaging
Pars bracket sign (96%)	Pars bracket sign (96%) • Paired pars marginalis at or behind the CS	Neurologic Imaging
Proton MR spectroscopy:	MR spectroscopy shows the distribution of brain metabolites based on the chemical shift of the protons within them - Choline: considered a tumour marker. Elevation of the choline to the creatinine ratio may help distinguish radiation necrosis from recurrent tumour or infection. Choline peak used for tumour grading,  Identifying the area of highest Choline to Creatine ratio for biopsy If the choline peak is sky high thin about meningioma Demyelinating preocesses such as Multiple Sclerosis can also present with Choline Peaks - NAA Decreas in NAA-to-creatinine ratio shows neuronal cell death, focal decrease NAA is seen in mesotemporal sclerosis and infarts Global decrease in NAA is seen in multiple sclerosis and demyelinating disease Alzheimers Disease AD, whih also elevates myoinositol Space occupying lesions with have a small NAA peak, Abscesses and metastatic lesions have lower NAA-to-creatinine ratios then primary brain tumors Markedly elevated NAA - Canavan's Disease as a result of a specific enzyme that metabolises it. Non-specific lipid necrosis peak seen in malignant tumours, infections, and some demyelinating lesions Aminoacid peaks are seen in in intracranial infections Double peak of lactic acid seen with ischemia - useful in infants with hypoxic ischemic encephalopathy, and aid in mitochondral encephalopathies	Neurologic Imaging
Sigmoidal hook sign	Sigmoidal hook sign (89%-98%) • Hooklike configuration of the central sulcus corresponding to the motor hand area	Neurologic Imaging
Signet sign	Signet sign: eccentric vessel lumen with surrounding thrombus Giant aneurysm	Neurologic Imaging
Sulcus/pre-CS sign	Superior frontal sulcus/pre-CS sign (85% specific) • The posterior end of the superior frontal sulcus joins the pre-CS	Neurologic Imaging
Thin post-central gyrus sign (98%)	Thin post-central gyrus sign (98%)	Neurologic Imaging
toothpaste sign	MRI Extruded disk material gives rise to the toothpaste sign (disk material is extruded from disk into the spinal canal like toothpaste); the material may be continuous with the disk (simple herniation) or be separated (free fragment herniation). Posterior disk herniation	Neurologic Imaging
tramtrack sign”	• Linear bands of enhancement (nerve within tumor): “tramtrack sign” optiC nerve MeningioMa	Neurologic Imaging
vacuum sign	Plain films • The diagnosis of herniation is not possible by plain film. • All findings of degenerative joint disease (e.g., narrowing of disk space, spurring, eburnation, vacuum sign) may appear in patients with or without herniation. Posterior disk herniation	Neurologic Imaging
White cerebellum sign	• White cerebellum sign: sparing of brainstem in comparison with hemispheres diFFuse CerebraL edema	Neurologic Imaging
Cystic duct sign	• Morphine is often given before 4 hours to make the diagnosis of acute cholecystitis. Dose is 0.04 mg/kg given slowly. Causes spasm of sphincter of Oddi Can convert true-positive result in case of cystic duct sign to false-negative result	Nuclear Imaging
DIFFUSE PERIOSTEAL UPTAKE (TRAMTRACK SIGN)	Criteria: bilateral, diffuse periosteal uptake • Hypertrophic osteoarthropathy (lower extremity > upper extremity) • Child abuse • Thyroid acropachy	Nuclear Imaging
dilated cavity on initial but not delayed images	Heart size and wall thickness • Subjective assessment • Transient cavitary dilatation (dilated cavity on initial but not delayed images) is a sign of LV dysfunction.	Nuclear Imaging
Hot nose sign	Imaging Findings • No flow Absent ICA Absent sinuses • Absent cerebral uptake of HMPAO • Slight perfusion of scalp veins may be present. • Hot nose sign: increased intracranial pressure results in increased flow to external carotid system BraIN Death StUDY	Nuclear Imaging
Lambda sign and Panda sign	• Sarcoid activity Lambda sign: bilateral hilar and paratracheal uptake Panda sign: lacrimal gland uptake	Nuclear Imaging
Rim sign:	patterNS IN hIDa StUDIeS (Fig. 12-49) GB Not Visualized Give morphine to increase pressure or cholecystokinin to contract GB. Causes: • Acute cholecystitis Rim sign: suggestive of gangrenous cholecystitis • Prolonged fasting • Recent meal	Nuclear Imaging
Ring Sign	• Late torsion • Tumor • Abscess • Trauma	Nuclear Imaging
Ring sign	NOrMaL IMaGeS • Slight uptake of tracer in both testes • Testes cannot be separated from scrotum. • Bladder activity is usually seen superior to testes. Interpretation Flow images • Increased (hyperemia) or not increased (no hyperemia) • Decreased flow cannot be detected. Static images • Cold testes • Ring sign • Hot testes TESTICULAR IMAGING Ring Sign • Late torsion • Tumor • Abscess	Nuclear Imaging
Ring sign or “bull's eye”  “Nubbin sign”	tOrSION Imaging Findings (Fig. 12-28) • Photopenic (“cold”) testis indicates torsion. • “Ring sign” or “bull's eye”: peripheral rim of increased activity with central zone of photopenia may represent inflammation of dartos and infarcted/necrotic testis. • “Ring sign”: delayed/missed torsion (the more pronounced the rim, the later the torsion or scrotal abscess) • “Nubbin sign”: area of increased activity that extends from the iliac arteries and ends at the torsion. Indicates increased perfusion to the scrotum via the pudendal arteries. Late torsion Variable flow images  Cold testis, hyperemic scrotum (ring sign) on static images Testes Abscess can be seen as a ring sign	Nuclear Imaging
sail sign.	• Thymus uptake: sail sign.	Nuclear Imaging
Stripe Sign	This sign refers to a perfusion abnormality with a zone of preserved peripheral perfusion. Because PE is pleural based, presence of this sign makes PE unlikely.	Nuclear Imaging
tie sign	SUperSCaN Criteria: diffuse high bone uptake, diminished soft tissue and renal activity, high sternal uptake (tie sign), increased uptake at costochondral junction (beading). Metastases (usually also causes focal abnormalities) • Prostate metastases (most common) • Lung cancer • Breast cancer Metabolic • Hyperparathyroidism • Renal osteodystrophy • Osteomalacia • Paget disease (hot and cold lesions are typically combined Myeloproliferative disease • Myelofibrosis (large spleen)	Nuclear Imaging
traMtraCK SIGN	DIFFUSe perIOSteaL UptaKe (traMtraCK SIGN) Criteria: bilateral, diffuse periosteal uptake • Hypertrophic osteoarthropathy (lower extremity > upper extremity) • Child abuse • Thyroid acropachy	Nuclear Imaging
trident sign	Technique: After intrathecal injection of radiotracer, normal activity is seen in basal cisterns at 2-4 hours (trident sign), over convexities at 24 hours, and there is no reflux into ventricles. Indications: NPH, VP shunts, CSF leaks.	Nuclear Imaging
Absent double decidual sign with MSD >10 mm	prediCtors of poor outCome in first trimester	Obstetric Imaging
Anterior uterine wall displaced away from fetal body	normal amniotiC fluid Volume Several methods are used for assessment of fluid; there is no evidence that any method is better than the other: • Subjective assessment (recommended by most sonographers) Anterior uterine wall displaced away from fetal body (good sign)	Obstetric Imaging
Banana sign (spina bifida)	Banana sign (spina bifida), Posterior fossa Cerebellar view • Banana sign (Fig. 10-28): represents the cerebellum wrapped around the posterior brainstem secondary to downward traction of the spinal cord as part of Arnold-Chiari malformation • Most cases of spina bifida are suspected because of head abnormalities (e.g., banana sign).	Obstetric Imaging
Double decidual sac sign	Pregnancy? • Visualize gestational sac • Double decidual sac sign Double Decidual Sac Sign (Fig. 10-6) The double decidual sac sign is a useful early sign of IUP. It is based on the demonstration of three layers of different echogenicity: • Decidua parietalis (hyperechoic) • Fluid in the uterine cavity (hypoechoic) • Decidua capsularis (hyperechoic) The double-bleb sign refers to the presence of an amnion and yolk sac at 5 to 6 weeks. The embryo lies between these two structures. • Pseudogestational sacs have an absent double decidual sign. • No double decidual sign but rather a single rim of echoes around pseudogestational sac seen in ectopic pregnancy	Obstetric Imaging
Double Decidual Sac Sign	The double decidual sac sign is a useful early sign of Intra uterine pregnancy. It is based on the demonstration of three layers of different echogenicity: • Decidua parietalis (hyperechoic) • Fluid in the uterine cavity (hypoechoic) • Decidua capsularis (hyperechoic)	Obstetric Imaging
Double-bubble sign	• Double-bubble sign (can be seen as early as 24th week of gestation) duodenal atresia	Obstetric Imaging
fluid around urinary bladder	US Features of Hydrops Fetalis • Effusions Ascites (fluid around urinary bladder) is the first and most reliable sign.	Obstetric Imaging
Gross Polyhydramnios	Gross polyhydramnios has a higher association with fetal anomalies than mild polyhydramnios. Associated anomalies include anencephaly, encephalocele, GI obstructions, abdominal wall defects, achondroplasia, and hydrops (isoimmunization).	Obstetric Imaging
Interstitial line sign	Interstitial line sign: hyperechoic endometrial line abuts but does not surround sac	Obstetric Imaging
Lambda sign	• Lambda sign: chorion extending into intertwin membrane Dichorionicity	Obstetric Imaging
Lemon Sign	• Chiari II, myelomeningocele • Encephalocele	Obstetric Imaging
Lemon sign (skull deformity)	• Lemon sign (skull deformity) enCephaloCele Indirect signs • Lemon sign (Fig. 10-27): bifrontal indentation. In 90% of fetuses with spina bifida <24 br="" weeks.=""> In older fetuses (24 to 37 weeks), lemon sign disappears. Lemon sign is rarely seen in a normal fetus. spina bifida and myelomeningoCele Lemon Sign • Chiari II, myelomeningocele • Encephalocele	Obstetric Imaging
Oreo cookie sign	• Adrenal glands can be mistaken for kidneys (hypoechoic rim, echogenic center: Oreo cookie sign	Obstetric Imaging
separating amnion	• Failure to identify a separating amnion is not a reliable sign to diagnose monoamnionicity.	Obstetric Imaging
Spalding's sign	fetal death • No fetal heart beat • Absent fetal movement • Occasional findings: Overlapping skull bones (Spalding's sign) Gross distortion of fetal anatomy (maceration) Soft tissue edema: skin >5 mm	Obstetric Imaging
The double-bleb sign	The double-bleb sign refers to the presence of an amnion and yolk sac at 5 to 6 weeks. The embryo lies between these two structures.	Obstetric Imaging
The double-bleb sign	The double-bleb sign refers to the presence of an amnion and yolk sac at 5 to 6 weeks. The embryo lies between these two structures.	Obstetric Imaging
Tubal ring sign (95% chance of ectopic	Tubal ring sign (95% chance of ectopic): echogenic rim surrounding an unruptured ectopic pregnancy	Obstetric Imaging
Twin peak sign	Twin peak sign	Obstetric Imaging
Adynamic ileus, Pneumatosis intestinalis,  Gas in portal vein may be seen transiently,  Pneumoperitoneum football sign	NeCrotiziNg eNteroColitis (NeC) Radiographic Features (Fig. 11-30) • Small bowel dilatation: adynamic ileus (first finding), unchanging configuration over serial radiographs • Pneumatosis intestinalis, 80% (second most common sign) • Gas in portal vein may be seen transiently (US more sensitive than plain film); this finding does not imply as bad an outcome as it does in adults. • Pneumoperitoneum (20%) indicates bowel perforation: football sign (floating air and ascites give the appearance of a large elliptical lucency in supine position). • Barium is contraindicated; use water-soluble contrast if a bowel obstruction or Hirschsprung disease needs to be ruled out.	Pediatric Imaging
Bilateral. C sign in subtalar bony coalition.	tarsal CoalitioN (Fig. 11-69) Fusion of 2 or more tarsal bones. Union may be complete, partial, bony, cartilaginous, or fibrous. Present at birth but usually asymptomatic until early adulthood. Location: • Calcaneonavicular (most common) • Talocalcaneal (common) Commonly results in spastic flatfoot. Bilateral. C sign in subtalar bony coalition.	Pediatric Imaging
doublebubble sign	CoNgeNital duodeNal atresia, steNosis Results from failure of recanalization (around 10 weeks). Incidence: 1:3500 live births. Atresia : stenosis = 2:1. Common cause of bowel obstruction. Bilious vomiting occurs within 24 hours after birth. Treatment is with duodenojejunostomy or duodeno duo denostomy. Associations • 30% have Down syndrome. • 40% have polyhydramnios and are premature. • Malrotation, EA, biliary atresia, renal anomalies, imperforate anus with or without sacral anomalies, CHD Radiographic Features • Enlarged duodenal bulb and stomach (doublebubble sign) • Small amount of air in distal small bowel does not exclude diagnosis of duodenal atresia (hepatopancreatic duct may bifurcate in “Y” shape and insert above and below atresia).	Pediatric Imaging
drooping lily sign	• Diminished number of calyces compared with normal side; drooping lily sign	Pediatric Imaging
fallen fragment sign	CommoN pediatriC boNe tumors Primary • EG • Ewing sarcoma • OSA • Bone cysts UBC: single cavity, fallen fragment sign ABC: eccentric Secondary • Neuroblastoma metastases • Lymphoma • Leukemia	Pediatric Imaging
Fat pad sign	Fat pad sign (posterior pad is normally absent, anterior fat pad is usually present); absence of the posterior fat pad sign virtually excludes a fracture (90% of patients with fat pad sign have a fracture) elboW iNjuries	Pediatric Imaging
hematogeNous osteomyelitis	Plain film (Fig. 11-57) • Soft tissue swelling (earliest sign; often in metaphyseal region), blurring of fat planes, sinus tract formation, soft tissue abscess • Cortical loss (5 to 7 days after infection), bone destruction hematogeNous osteomyelitis	Pediatric Imaging
Neuhauser's sign	Plain film • Neuhauser's sign: “Soap bubble” appearance (air mixed with meconium) • Small bowel obstruction • Calcification due to meconium peritonitis, 15% Enema with water-soluble contrast medium • Microcolon is typical: small unused colon • Distal 10 to 30 cm of ileum is larger than colon. • Inspissated meconium in terminal ileum • Hyperosmolar contrast may stimulate passage of meconium. meCoNium ileus	Pediatric Imaging
Ortolani's jerk or click sign           Barlow's sign	Clinical Findings deVelopmeNtal dysplasia oF the hip (ddh) (CoNgeNital disloCatioN oF the hip) • Ortolani's jerk or click sign: relocation click while abducting hip with thumb and placing pressure on greater trochanter • Barlow's sign: dislocation click while adducting hip with pressure on knee • Limited abduction of flexed hip • Shortening of one leg • Waddling gait	Pediatric Imaging
shoulder sign string sign	Upper gastrointestinal (UGI) findings of HPS: • Indented gastric antrum (shoulder sign) • Compression of duodenal bulb • Narrow and elongated pylorus: string sign hypertrophiC pyloriC steNosis (hps)	Pediatric Imaging
Steeple sign:	Radiographic Features (Fig. 11-6) • Subglottic narrowing (inverted “V” or “steeple sign”) • Key view: AP view • Lateral view should be obtained to exclude epiglottitis. • Steeple sign: loss of subglottic shoulders	Pediatric Imaging
Stripe Sign	Stripe Sign (Fig. 12-4) This sign refers to a perfusion abnormality with a zone of preserved peripheral perfusion. Because PE is pleural based, presence of this sign makes PE unlikely. PE absent 1. Normal perfusion 2. Very low probability 3. Nonsegmental lesion; e.g., prominent hilum, cardiomegaly, elevated diaphragm, linear atelectasis 4. Perfusion defect smaller than radiographic lesion 5. A solitary CXR-Q matched defect in the mid or upper lung confined to a single segment 6. Stripe sign around the perfusion defect 7. Pleural effusion ≥ one third of the pleural cavity with no other perfusion defect in either lung	Pediatric Imaging
Target or doughnut sign	IntussusCeption Radiographic Features Plain film • Frequently normal (50%) • Intraluminal convex filling defect in partially air-filled bowel loop (commonly at hepatic flexure) Ultrasound (US) • Target or doughnut sign	Pediatric Imaging
Widened joint	Radiographic Features (Fig. 11-61) Early phase • Widened joint: may be due to increased cartilage or joint effusion (earliest sign) • Subchondral fissure fracture, best seen on frogleg view (tangential view of cartilage) • Increase in bone density Intermediate phase • Granular, fragmented appearance of femoral epiphysis due to calcification of avascular cartilage (no fracture of epiphysis) • Lateralization of ossification center • Cysts of demineralization (30%) • Apposition of new bone makes the femoral head appear dense. Late phase • Flattened and distorted femoral head • Osteoarthritis (OA) legg-CalVé-perthes (lCp) disease	Pediatric Imaging
Wimberger's sign Wimberger's corner sign	Syphilis Bone changes may lag infection by 6 to 8 weeks. Radiographic Features • Metaphyseal lucent bands • Symmetrical periosteal reaction • Wimberger's sign (bilateral destructive lesion on medial aspect proximal tibial metaphysis) • Should not be confused with Wimberger's ring (dense ring of demineralized epiphysis seen in scurvy)	Pediatric Imaging
Biological Effects of radiation: Stocastic (delayed) effects and Non-stocastic (deterministic) effects	Stocastic (delayed) effects - cancers in exposed individual: observed 3-20 years after exposure ; - Mutations in offspring of exposed individual - observed in future generations Probability of effect increases with dose, with no dose threshold, but the severity of the effect is not dose related. E.g. radiation induced cancer and genetic effects. Playing the Lottery game, more exposure, more chances of effect. Cancer risk: average risk for radiation induced cancer in general population is 5% per Sievert (Sv); Children are 2-3 times at higher risk then adults (as high as 15% per Sv); for persons aged >50 yars risk is 1/5 to 1/10 of the for younger adults Non-stocastic (deterministic) effects: - direct damage to tissue due to local cell death; - observable within days to weeks Threshold dose; >2 Grey of radiation	Radiation Risk
Ratiation Protection Pillars Time; Distance; Shielding	Primary radiation limited to detector field Secon	Radiation Risk
Adrenal hemorrhage	Etiology: Underlying tumor; Coumadin; Trauma; Infection; Hypercoagability states; stress CT findings: high attenuation on NECT; may be unilateral or bilateral; in time may calcify; more common in females (3:1) If bilateral adrenal hemorrhage in trauma consider addison syndrome need hormonal replacement therapy as life treatening (Emergency Radiology 2012; Sacerdote) Variable appearnace of lesion: Round;	Trauma
Blunt abdominal trauma findings:	Adrenal hematoma (oval or round); irregular hemorrhage obliterating the gland; uniform adrenal gland swelling with increased attenuation; preiadrenal hemorrhage or stranding; retroperitoneal hemorrhage; adrenal pseudocyst (chronic) (Emergency radiology 2012 To'o)	Trauma
Bright Adrenals in Trauma	Patient is hypotensive; hypovolemic shock syndrome	Trauma
Hypovolemic shock CT findings	Bright Adrenals; Diffuse fluid filled dilated small bowel; hyperenhancement of the small bowel; hyperenhancement of the gall bladder mucosa; reduced splenic perfusion; intense enhancement of the kidneys; peripancreatic edema (BMJ 2008). Also look for a flat IVC	Trauma
Pelvic fracture in a pregnant patient	In major trauma, when there is concern for maternal injury, CT is the mainstay of imaging. The risks of radiation to the pregnancy are small compared with the risks of missed or delayed diagnosis of trauma. (Imaging of trauma, abdominal trauma in prenancy, Sadro AJR 2012) Trauma is the leading caue of non-obstatric maternal mortality affecting up to 7% of pregnancies and is significant cause of fetal loss. Approximately 2% of level-1 trauma patients have a positive pregnancy test. Soft tissue / muscle injury; pelvic hematoma; bladder injury; colon injury Bladder trauma: Blunt 60%, Penetrating 35% IAtrogenic 5% GU trauma occurs in 5-10% of all patients with trauma; bladder injury occurs in 1.6% of blunt trauma cases; bladder rupture occurs in 2-11% of patients with pelvic trauma; however, 60-90% of patients with bladder rupture have a pelvic fracture 80% of cases are extraperitoneal rupture; 15% of cases are intraperitoneal; 5% of cases are combined bladder rupture Intraperitoneal rupture has a higher morbidity and mortality 5 Bladder trauma categories: contusion; intraperitoneal (15%), interstitial or bladder wall hematoma; extraperitoneal (80%), combined (5%) - lower urinary tract trauma (Sandler, World J Urology) 15% of rupture intraperitoneal- delayed diagnosis results in increased mortality due in part to risk of chemical peritonitis; patients require surgical management MDCT cystography os rapidly becoming the most recommended study for evaluation of th bladder for suspected trauma (Emergency radiology 2011, IShak) MDCT cystography should be done when pelvic fluid is present, especially when there are fractures or gross hematuria, to define which of the patients has a bladder rupture and to define the type of bladder rupture.	Trauma
Splenic bleed and subsequent rupture	Active bleeding, multiple, areas	Trauma
Vascular injuries in Pelvic fractures	Active arterial extravasation, occlusion, intimal injury and occlusion, peudoaneurysm, arterial dissection, arteriovenous fistulae, venous injury	Trauma
Draped aorta sign	Draped aorta sign: posterior wall of the aorta either is not identifiable or closely follows vertebral bodies	Vascular Imaging
Hyperattenuation crescent sign	• Hyperattenuation crescent sign: welldefined peripheral crescent of increased attenuation within the thrombus of a large aneurysm indicates acute or impending rupture	Vascular Imaging
loss of “wink” sign	Noncompressibility of vein (loss of “wink” sign) DVT	Vascular Imaging
popliteal “dog-leg” sign (aCute bend in the lumen of the popliteal artery)	• Popliteal aneurysm: Most common peripheral arterial aneurysm. 50% of aneurysms are bilateral, and 80% are associated with aneurysm elsewhere. Commonly due to atherosclerotic disease or trauma. Angiography may show luminal dilatation or mural calcification. 25% of popliteal artery aneurysms may not be associated with visible arterial dilatation by angiography. In these cases, secondary signs such as the “dog-leg sign” (acute bend in lumen of the popliteal artery) may be helpful. Complications of aneurysm include distal embolization and thrombosis, resulting in ischemia. Rupture is uncommon.	Vascular Imaging
Popliteal “dog-leg” sign (acute bend in the lumen of the popliteal artery)	• Popliteal aneurysms (if bilateral, 80% also have AAA) • Tortuous artery • Popliteal artery entrapment syndrome (accentuated arterial narrowing with passive dorsiflexion or active plantar flexion at arteriography) • Adventitial cystic disease (no flow on US) • Baker's cyst (no flow on US)	Vascular Imaging
pseudovein” sign	Extravascular contrast extravasation is the hallmark of active bleeding. Accumulation in bowel lumen Gastric “pseudovein” sign (contrast between rugal folds) Filling of pseudoaneurysm or pooling upper gi hemorrhage	Vascular Imaging
Vascular Complications of Ehlers-Danlos Syndrome CT Angiography and 3D mapping	Ehlers Danlos Syndrome EDS: group of clinically and genetically heterogeneous heritable connective tissue disorders; characterised by joint hypermobility, skin hyperextensibility, tissue fragility; six forms of EDS are currently recognised; disease related symptoms vary based on each EDS type Vascular EDS (type IV), AD; heterogeneous mutations in the COL3A1 gene and encoding for Type III procollagen; Excessive tissue fragility predisposing to premature arteria;, intestinal or uterine rupture 2 of 3 Major criteria: Thin translucent skin; Arterial, intestinal, uterine fragility or rupture; extensive bruising; characteristic facial appearance Minor criteria: Acrogeria (slender face, sunken cheeks, thin nose and lips); Hypermobility of small joints; tendon and muscle rupture; talipes equiovarus; anteriovenous, carotid-cavernous sinus fistula; pneumothorax, pneumohemothorax; gingival recession; positive family history, sudden death in close relative Patients deveop vascular lesions at a young age; aneurysms, dissection, occlusion, stenosis; lesions frequently involve multipe vascular segments; can be isolated to a single vascular segment; frequently involve abdominal viseral arteries; iliac arteries; thoracic and abdominal aorta Complications: Spontaneous aneurysm rupture; progression of pre-existing aneurysms; development of new aneurysms; dissection and vascular occlusions	Vascular Imaging
Vascular sign	Vascular sign; acute embolus in a dilated vessel leading to apex of consolidation	Vascular Imaging
Vessel cutoff sign rim sign on axial and tramtrack sign on long axis view	CT Pulmonary Angiography (CTPA) Direct findings of PE • Direct visualization of filling defect • Vessel cutoff sign: distal artery is not opacified due to occlusive embolus • Occluded artery is larger than the normal artery on the opposite side • Partial occlusion can cause rim sign on axial and tramtrack sign on long axis view Indirect findings of PE • Pulmonary hemorrhage; usually resolves in a week	Vascular Imaging