any break in the bony ring of a vertebra that occurs on a slice that shows the __________ _______ is a spondylolysis until proved otherwise?
basivertebral plexus
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?
"Achondroplasia
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?
Spondylolysis
Anterior displacement of a cephalad vertebral body with respect to a caudad vertebral body?
"Spondylolisthesis. Grade I (<25%)
Most common site for coalition?
Calcaneonavicular joint.
Finding causing the greatest concern for metastatic bone disease or multiple myeloma involvement?
A permeative process.
Spinal hemangioma CT features?
"vertical trabecular thickening
Schmorl's node?
Herniation of disk material through end plate of vertebral body.
Tarlov cysts?
"Nerve sheath dilatations of fluid density at CT
Paget's disease on CT?
"Purely lytic or sclerotic or mixed. Bone overgrowth
Fibrous dysplasia?
"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?
"Smooth
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."
Air-crescent sign?
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?
"Diffuse (granuloma)
Benign pulmonary nodule doubling times?
" < 1 month
What increase in diameter equals a doubling of volume?
26% increase (10 mm to 12.6 mm)
"Differential
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?
"CF-bilateral
Causes of interlobular septal thickening as predominant finding at HRCT?
Common causes of fibrosis and honeycombing as predominant HRCT findings?
"IPF 65%
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?
"Random distribution
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?
"Perilymphatic nodules
HRCT findings in end-stage sarcoidosis?
"Irregular septal thickening
Pulmonary lymphangitic spread of carcinoma?
"Interlobular septal thickening
Pulmonary hematogenous spread of tumor?
"Random distribution
Idiopathic pulmonary fibrosis CT features?
"Intralobular thickening
Nonspecific interstitial pneumonia CT features?
"Ground-glass opacity
Collagen vascular disease as lung disease?
"Rheumatoid lung
Active pulmonary sarcoidosis CT features?
"Perilymphatic nodules
End-stage sarcoidosis?
"Irregular septal thickening
Silicosis and Coal Worker's pneumoconiosis?
"Perilymphatic nodules
Pulmonary Tuberculosis CT features?
"Endobronchial spread (centrilobular nodules
Pulmonary alveolar proteinosis?
"Filling of alveolar spaces with lipid-rich proteinaceous material
"Hypersensitivity pneumonitis
subacute stage CT features?"
"Bronchiolitis obliterans organizing pneumonia
causes?"
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)
Lymphangiomyomatosis?
"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?
empyema necessitatis.
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?
"Aorta
What passes through the esophageal hiatus?
"Esophagus
Anterior mediastinal node groups?
"Internal mammary nodes
Middle mediastinal node groups?
"Pretracheal or paratracheal nodes
Posterior mediastinal node groups?
"Paraesophageal nodes
Upper limits of normal for subcarinal lymph node diameter?
1.5 cm
"Egg-shell calcified mediastinal lymph node
differential?"
"Calcified mediastinal lymph node
differential?"
Mediastinal lymph node enhancement?
"Castleman's disease
Left upper lobe cancers involve what mediastinal lymph node group?
Aortopulmonary window nodes
Lower lobe lung cancers involve what mediastinal lymph node group?
Subcarinal nodes
Resectability non-small cell lung cancer stages?
"Stage IIIb-IV
Sarcoidosis thoracic adenopathy features?
"Symmetric hilar adenopathy
Prevascular space tumors?
"4Ts: thymoma
Castleman's disease
"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
Thymic masses?
"Thymoma
Three main categories of germ-cell tumors?
"1. Teratoma and dermoid cyst
Teratoma versus dermoid cyst?
"Teratoma contains ecto-
Lymphangioma types?
"Simple--small
Saber-sheath trachea features?
"Narrowed lateral dimension of intrathoracic trachea. COPD
Concentric tracheal narrowing causes?
"Intubation
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?
Meningocele
Granulomatous mediastinitis causes?
"Histoplasmosis
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?
Medial Lateral
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?
"Silicosis
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?
"Retroperitoneal space
Perineum
"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?
"SCC 85%
Endometrial malignancy features?
"hypodense mass within endometrial cavity
Ovarian cancer features?
"cystic 66%
Normal ovarian follicle size?
<3 cm
Functional ovarian cyst features?
"Benign follicular or corpus luteum cysts
PID CT features?
"Thickening of fallopian tubes (early)
"Adnexal torsion
CT features?"
Testicular cancer lymph node involvement?
"Gonadal lymphatics (testicular veins and renal hilar nodes)
Aberrant right subclavian artery?
"Left arch
Two types of right aortic arch?
"Right arch with aberrant left subclavian
Double aortic arch?
"Vascular ring with dysphagia
Ascending aortic aneurysm causes?
"atherosclerosis
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?
"supra-aortic mediastinum
Mediastinal spaces and recesses?
"Pretracheal space
Persistent left superior vena cava features?
"Failure of cardinal vein to regress
Azygos or hemiazygos continuation of IVC?
"Hemiazygos (polysplenia)
Causes of SVC syndrome?
"Most commonly bronchogenic carcinoma
Pulmonary artery diameter in pulmonary hypertension?
">3 cm
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?
"Causes (alcohol
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?
"Crohn's disease
Complications associated with perforated appendicitis?
"Phlegmon (periappendiceal soft-tissue mass)
Mucocele of appendix?
"Distended
Diverticulitis CT features?
"Small
Colitides?
"Ulcerative colitis
CT features of islet cell tumors?
"Small tumors (<4 cm) enhance. Large tumors heterogeneous with calcification
"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?
"Lymphoma (masses
Crohn's disease CT features?
"Terminal ileum 80%
Complete mechanical SBO?
"Dilatation of SB > 2
Paralytic ileus?
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?
"Cystic lymphangiomas
Mesenteric neoplasms?
"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?
"Diffuse infiltration
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