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A burst fracture of the C1 ring?
any break in the bony ring of a vertebra that occurs on a slice that shows the __________ _______ is a spondylolysis until proved otherwise?
Helps distinguish myositis ossificans from parosteal osteosarcoma?
Parosteal sarcoma demonstrates central clumps of calcification and myositis ossificans has peripheral ossification/calcification.
"Define disk bulge
sequestered or free fragment?"
Distinguishing a free fragment from a Tarlov cyst or conjoined nerve root?
A free fragment is hyperdense to thecal sac and Tarlov cyts and conjoined nerve roots are isodense to thecal sac.
Lateral disk protrusion affects what nerve root?
A nerve rooth that has already exited the neuroforamen at a more cephalad level.
Congenital causes of spinal stenosis?
Acquired spinal stenosis causes?
"Degenerative disk disease
Anatomic classification of spinal stenosis?
"Central canal stenosis
Most useful CT criteria for diagnosing central canal stenosis?
"Obliteration of epidural fat
Pars interarticularis defect?
Anterior displacement of a cephalad vertebral body with respect to a caudad vertebral body?
"Spondylolisthesis. Grade I (<25%)
Most common site for coalition?
Finding causing the greatest concern for metastatic bone disease or multiple myeloma involvement?
A permeative process.
Spinal hemangioma CT features?
"vertical trabecular thickening
Herniation of disk material through end plate of vertebral body.
"Nerve sheath dilatations of fluid density at CT
Paget's disease on CT?
"Purely lytic or sclerotic or mixed. Bone overgrowth
"Congenital disorder of bone
Common right-sided anomalous pulmonary venous return insertions?
"SVC azygos vein
Common left-sided anomalous pulmonary venous return insertions?
"Left brachiocephalic vein
CT features that suggest lung cancer?
"Irregular or spiculated margine
Lung hamartoma CT features?
4 findings of rounded atelectasis?
"1. Ipsilateral pleural thickening or effusion. 2. Contact between lung lesion and pleural surface. 3. ""comet tail"" sign. 4. Volume loss of lobe involved."
Lung mass capped by a crescent of air. Most typical of mycetoma (fungus ball). Fungus ball (Aspergillus) forms in preexisting cyst or cavity.
Lung abscess CT features?
Necrosis or cavitation within area of pneumonia or dense consolidation.
Satellite nodules and galaxy sign?
"Granulomatous lesions with smaller nearby nodules--satellite. In sarcoidosis
Benign pulmonary nodule calcification patterns?
Benign pulmonary nodule doubling times?
" < 1 month
What increase in diameter equals a doubling of volume?
26% increase (10 mm to 12.6 mm)
multiple large pulmonary nodules?"
Pulmonary metastasis characteristics?
Typically round and well-defined. Cavitation and calcification can be seen.
Signet ring sign?
"Bronchiectasis. Cross section of pulmonary artery branch adjacent to dilated
Bronchiectasis patterns in cystic fibrosis and allergic bronchopulmonary aspergillosis?
Causes of interlobular septal thickening as predominant finding at HRCT?
1. Lymphatic spread of carcinoma. 2. Interstitial pulmonary edema. 3. Alveolar proteinosis. 4. Sarcoidosis.
Common causes of fibrosis and honeycombing as predominant HRCT findings?
3 distributions of pulmonary nodules at HRCT?
"Perilymphatic nodules (pleural surface
CT features of pulmonary lymphangitic spread of carcinoma?
"Interlobular septal thickening
CT features of pulmonary hematogenous spread of tumor?
CT features of IPF (idiopathic pulmonary fibrosis--UIP is histology pattern)?
"Intralobular interstitial thickening
"Nonspecific interstitial pneumonia (NIP
collagen vascular disease) CT features?"
Active sarcoidosis CT features?
HRCT findings in end-stage sarcoidosis?
"Irregular septal thickening
Pulmonary lymphangitic spread of carcinoma?
"Interlobular septal thickening
Pulmonary hematogenous spread of tumor?
Idiopathic pulmonary fibrosis CT features?
Nonspecific interstitial pneumonia CT features?
Collagen vascular disease as lung disease?
Active pulmonary sarcoidosis CT features?
"Irregular septal thickening
Silicosis and Coal Worker's pneumoconiosis?
Pulmonary Tuberculosis CT features?
"Endobronchial spread (centrilobular nodules
Pulmonary alveolar proteinosis?
"Filling of alveolar spaces with lipid-rich proteinaceous material
subacute stage CT features?"
"Bronchiolitis obliterans organizing pneumonia
HRCT features of bronchiolitis obliterans organizing pneumonia?
"Patchy or nodular consolidation
Chronic eosinophilic pneumonia?
"Filling of alveoli by mixed inflammatory infiltrate (eosinophils)
Histiocytosis (aka Langerhans histiocytosis or eosinophilic granuloma)?
"Centrilobular nodules (may cavitate)
"Women of child bearing age
List 4 types of emphysema?
"Centrilobular (upper lobes
Split pleura sign?
Thickened visceral and parietal pleural layers are split apart and surround an empyema.
Extension of an empyema to involve the chest wall is termed?
Lung abscess versus empyema CT characteristics?
"Abscess (poorly defined
CT features of a malignant effusion?
"Nodular pleural thickening
CT findings for chest wall invasion?
"Extensive contact between tumor and chest wall (> 3cm or ratio > 0.7)
What passes through the aortic hiatus?
What passes through the esophageal hiatus?
Anterior mediastinal node groups?
"Internal mammary nodes
Middle mediastinal node groups?
"Pretracheal or paratracheal nodes
Posterior mediastinal node groups?
Upper limits of normal for subcarinal lymph node diameter?
"Egg-shell calcified mediastinal lymph node
"Calcified mediastinal lymph node
Mediastinal lymph node enhancement?
Left upper lobe cancers involve what mediastinal lymph node group?
Aortopulmonary window nodes
Lower lobe lung cancers involve what mediastinal lymph node group?
Resectability non-small cell lung cancer stages?
Sarcoidosis thoracic adenopathy features?
"Symmetric hilar adenopathy
Prevascular space tumors?
"aka angiofollicular lymph node hyperplasia Focal form (Enhancing hilar or mediastinal lymph nodes) Diffuse form (Enhancing mediastinal
CT features of thymoma?
"Prevascular or paracardiac location
Three main categories of germ-cell tumors?
"1. Teratoma and dermoid cyst
Teratoma versus dermoid cyst?
"Teratoma contains ecto-
Saber-sheath trachea features?
"Narrowed lateral dimension of intrathoracic trachea. COPD
Concentric tracheal narrowing causes?
Bronchogenic and esophageal duplication cyst features?
"Anomalous budding of foregut. Most commonly within subcarinal space. Esophageal duplication cyst indistinguishable from bronchogenic
Paravertebral neurogenic tumor divisions?
"1. Peripheral nerve or nerve sheath (neurofibroma
Most common cause of posterior mediastinal mass in patients with neurofibromatosis?
Granulomatous mediastinitis causes?
Sclerosing mediastinitis versus granulomatous mediastinitis
Similar but no calcification with sclerosing mediastinitis.
Pericardial cyst features?
"60% anterior right cardiophrenic angle
Morgagni hernia features?
"Anteromedial diphragmatic foramen of Morgagni. Cardiophrenic angle mass
Right upper lung lobe segments?
Apical Posterior Anterior
Left upper lung lobe segments?
Apicoposterior Anterior Superior lingula Inferior lingula
Right middle lung lobe segments?
Right lower lung lobe segments?
Superior Anterior Medial Lateral Posterior
Left lower lung lobe segemnts
Superior Anteromedial Lateral Posterior
Egg-shell calcification of thoracic lymph nodes?
Pulmonary agenesis versus pulmonary aplasia?
Aplasia has rudimentary bronchus.
Pulmonary arteriovenous fistula features?
"Single dilated vascular sac or tangle of dilatated tortuous vessels. Mostly subpleural
Pulmonary sequestration features?
"Cystic or solid
Intralobar sequestration versus Extralobar sequestration?
"Intralobar: diagnosed in adults
Hypogenic lung sydrome (scimitar)?
"almost always on right side
Extraperitoneal space communicates with?
"Lies below pelvic diaphragm
Normal fertile ovary dimensions?
2 x 3 x 4 cm.
Bladder carcinoma CT features?
"Focal thickening of bladder wall
Uterine leiomyoma CT features?
"40% of women > 30 yo
Carcinoma of cervic features?
Endometrial malignancy features?
"hypodense mass within endometrial cavity
Ovarian cancer features?
Normal ovarian follicle size?
Functional ovarian cyst features?
"Benign follicular or corpus luteum cysts
PID CT features?
"Thickening of fallopian tubes (early)
Testicular cancer lymph node involvement?
"Gonadal lymphatics (testicular veins and renal hilar nodes)
Aberrant right subclavian artery?
Two types of right aortic arch?
"Right arch with aberrant left subclavian
Double aortic arch?
"Vascular ring with dysphagia
Ascending aortic aneurysm causes?
3 common locations for aortic trauma?
Aortic root level of ligamentum arteriosum diaphragm and aortic hiatus
Stanford aortic dissection types?
"Type A--involves ascending aorta (treated surgically: possibility of retrograde dissection and rupture within pericardium or occlusion of coronary or carotid arteries)
DeBakey's aortic dissection types?
"Type I--entire aorta
Three mediastinum compartments?
Mediastinal spaces and recesses?
Persistent left superior vena cava features?
"Failure of cardinal vein to regress
Azygos or hemiazygos continuation of IVC?
Causes of SVC syndrome?
"Most commonly bronchogenic carcinoma
Pulmonary artery diameter in pulmonary hypertension?
Difference in pulmonary dilatation in pulmonary hypertension and pulmonic stenosis?
"Pulmonic stenosis--main and left pulmonary arteries dilated. Pulmonary hypertension--mian
Acute PE versus chronic PE at CT?
"acute PE--clot centered in lumen
Acute pancreatitis CT findings?
Enlargement decrease in density blurring of margins peripancreatic stranding blurring of fat planes thickening of retroperitoneal fascia
Complications of acute pancreatitis?
Fluid collections Pseudocysts Necrosis (lack of enhancement) Phlegmon (mass of edema and inflammation) Abscess Hemorrhage Pseudoaneurysms Thrombosis (splenic vein) ascites
Chronic pancreatitis features?
CT features of pancreatic adenocarcinoma?
hypodense mass 96% head > body > tail
Signs of pancreatic adenocarcinoma resectability?
Isolated pancreatic mass Double duct sign without mass
Signs of pancreatic adenocarcinoma unresectability?
"Involvement of major arteries or veins. Extension of tumor beyond margins of pancreas
Appendicitis CT features?
"Distended appendix >6 mm
Differential of RLQ pain without abnormal appendix or appendicolith?
Complications associated with perforated appendicitis?
"Phlegmon (periappendiceal soft-tissue mass)
Mucocele of appendix?
Diverticulitis CT features?
CT features of islet cell tumors?
"Small tumors (<4 cm) enhance. Large tumors heterogeneous with calcification
Functioning islet cell tumors' malignant potential?
80% glucagonoma 60% gastrinoma 10% insulinoma
CT features of pancreatic lymphoma?
Metastases to pancreas CT features?
"Round or ovoid Most heterogeneous
Intraductal papillary mucinous neoplasm CT features?
"Diffuse or segmental dilation of pancreatic duct
Pseudocyst CT features?
"Most common cystic lesion in and around pancreas
Pancreatic mucinous cystic neoplasm CT features?
Pancreatic serous cystadenoma CT features?
"Posttraumatic cyst (most common)
Splenic microabscesses CT features?
"Multiple low-density lesions
Most common neoplasm of spleen?
Rare primary malignancy of spleen?
Multiple small focal splenic calcifications?
Histoplasmosis or TB.
Features of esophageal carcinoma?
"Lack of serosa
Esophageal leiomyoma features?
"Gastric cardia and gastroesophageal junction below esophageal hiatus
Gastric hernia rotations?
Organoaxial (long axis rotation). Mesenteroaxial (upside down stomach)
Gastric varcies without esophageal varices?
hallmark findikng of splenic vein thrombosis.
Small bowel malignant tumors?
Crohn's disease CT features?
"Terminal ileum 80%
Complete mechanical SBO?
"Dilatation of SB > 2
Dilatation of distal and proximal SB without transition zone
Partial mechanical SBO?
"Transition zone less distinct
Sclerosing mesenteritis features?
"Inflammatory disorder of unknown cause
Cystic mesenteric masses?
"Lymphoma (most common)
Colon volvulus types?
"Sigmoid volvulus (most common
Fibrolammelar Carcinoma CT features?
Large mass in healthy liver Enhances prominently and heterogeneously Central scar Difficult to distinguish from FNH
Liver lymphoma CT features?
Hepatic adenoma CT features?
"Young women on oral contraceptives. Men on anabolic steroids. Glycogen storage disease (multiple). Surgical removal for fear of rupture or malignant transformatoin. Unenhanced
FNH CT features?
"Mini liver central stellate scar and fibrous bands. Unenhanced
Cavernous Hemangioma CT features?
Cystic liver masses?
Hepatic cysts Pyogenic abscess Amebic abscess Hydatid cyst
Normal bile duct measurements?
Intrahepatic ducts 2 mm in central liver. Common duct < 6 mm. Give 1 mm per decade in elderly
CT findings of biliary obstruction?
"Dilated intrahepatic biliary ducts
Precursors of choriocarcinoma?
Choledochal cyst Primary sclerosing cholangitis Caroli's disease intrahepatic stone disease Clonorchiasis
cholangiocarcinoma CT features?
CT features of primary sclerosing cholangitis?
"Multiple segmental strictures (beaded appearance) with thickening of bile duct. Complications: obstruction
Choledochal cyst types?
CT findings of acute cholecystitis?
"Gallstones in gallbladder 75%
Gallbladder carcinoma CT features?
"Polypoid soft-tissue mass
CT features of lymphoma in abdomen
"Multiple enlarged nodes
CT features of AIDS in abdomen?
Surgical indications for splenic trauma?
Cortical rim sign?
Delayed finding. Faint enhancement of kidney periphery in renal infarction. Renal capsule supplied by separate arteries
Complications of pancreatic trauma?
Pseudocyst formation hemorrhagic pancreatitis Abscess Fistula
Severe hypotension and hypoperfusion of bowel. Diffuse dilation of small bowel with wall thickening and increased wall enhancement
Extraperitoneal bladder rupture?
"Contrast leakage into retropubic space
Intraperitoneal bladder rupture?
Contrast in paracolic gutters and surrounding bowel
Which adrenal gland more susceptible to traumatic injury?
Right adrenal gland. compression of gland between liver and spine.
Liver segment I?
Liver segments II and III?
Lateral division of left lobe. II-superior. III-inferior.
Liver segments IV?
Medial division of left lobe. IVa-superior. IVb-inferior.
Liver segments V and VIII?
Anterior segments of right lobe. VIII-superior. V-inferior.
Liver segments VI and VIII?
Posterior segments of right lobe. VII-superior. VI-inferior.
"Areas of liver supplied by aberrant systemic veins. Porta hepatis
Increased liver attenuation?
"Amiodarone Hemochromatosis (secondary form-hemosiderosis
Liver nodules in cirrhosis?
Regenerative nodules Dysplastic nodules Small HCC nodules Metastatic disease Hemangiomas
CT features of portal hypertension?
"Portosystemic collateral vessels Enlarged portal vein
CT features of Budd-Chiari syndrome?
Enlarged caudate lobe. Central liver enhances early and peripheral liver enhances late.
Clinically significant liver lesions?
Metastases Hepatoma Hepatic adenoma
Metastases to liver features on CT?
"Most common liver malignancy. Most commonly from colon. Target appearance. Hypervascular (carcinoid
HCC CT features?
"50% solitary tumor 30% infiltrative 20% multinodular Small tumors
How much must a renal mass enhance in Hounsfield units before it is considered enhanced?
10 - 15 H
Metastatic lymph node size in RCC?
> 2 cm nearly alwasy metastatic 1 - 2 cm indeterminate
Most common sites for RCC metastases?
lungs mediastinum bone liver contralateral kidney adrenal gland brain
Bosniak cystic renal mass categories?
Category I Benign simple cyst Category 2 Benign Complicated Category 3 Indeterminate cystic lesions Category 4 Malignant cystic tumors (enhancing soft tissue)
VHL and TS CNS involvement differences?
Emphysematous pyelonephritis versus emphysematous pyelitis?
"Emphysematous pyelonephritis: diabetes
Renal stone not seen at CT?
Crystallin stones related to indinavir (protease inhbitor HIV Rx)
What size renal stones can pass on their own?
< 4 mm nearly always pass. > 8 mm rarely pass.
Tissue rim sign?
Halo of soft tissue that surrounds ureter stone.
Absence of white pyramids?
Subtle sign of urinary obstruction on affected side.
"tail sign (vein)
Adrenocortical carcinoma features?
large > 5 cm Necrosis and calcification Delayed contrast washout
Adrenal calcification causes?
"In adrenal hyperplasia
adrenal limb thickness exceeds?"
Organ of Zuckerkandl?
Common location for extra-adrenal pheochromoctyoma. Near origin of IMA
Common metastases to adrenal glands?
Lung Breast Melanoma
Lipid-rich adrenal adenoma Hounsfield units?
< 10 H
Lipid-poor adrenal adenoma features?
Non-contrast H > 10 Enhancement washout > 50% 15 minute post-contrast H < 35
Serous ascites attenuation value in H?
-10 to +15
Hemoperitoneum attenuation value in H?
"With absence of intrahepatic segment of IVC
how does lower body venous blood reach the heart?"
Aneurysmal diameters of abdominal aorta and iliac arteries?
AAA > 3 cm Iliac aneurysm > 1.5 cm
Hyperattenuating crescent sign?
"Crescent area of high attenuation (dissecting contrast) within wall or intraluminal thrombus of AAA
Beak sign in distinguishing true lumen from false lumen in aortic dissection?
Intimal flap and false lumen wall create an acute angle: beak sign
Dilatation of vein at site of DVT means acute or chronic?
Abdominal and retrocrural lymph node pathologic size cutoff?
Abdominal LN > 10 mm. Retrocrural LN > 6 mm