Radiology OSCE Flashcards

Summary tables of follow-up questions that may get asked in the OSCER.

What percentage of the liver weight is considered steatosis?

Greater than 5% of the liver weight is intrahepatic fat.

What are some differential diagnoses for increased liver density?

Amiodarone, Wilson's disease, glycogen storage disease, hemochromatosis

What are the main causes of cirrhosis?

Alcohol, drugs, viral hepatitis, schistosomiasis, NASH, PBC, haemochromatosis, Wilson's, a1AT

What are risk factors for portal vein thrombosis?

Cirrhosis, HCC, cholangiocarcinoma, hypercoagulable state, IBD, OCP, pregnancy, trauma, pancreatitis, cholangitis

What are the ultrasound findings for Budd-Chiari syndrome?

Heterogeneous liver, caudate hypertrophy, regenerative nodules, no flow in hepatic veins, portal vein changes, IVC thrombus, ascites, increased hepatic artery RI

What is considered an increased hepatic artery Resistive Index (RI)?

Greater than 0.75

What CT/MRI findings are associated with liver abscesses?

CT: double target sign. MRI: T2 hyper, T1 hypo, capsular/septal enhancement, low ADC/high DWI within cavity, high DWI/ADC at periphery

What organisms are commonly found in liver abscesses?

Polymicrobial (E coli, Klebsiella, bacteroides)

What is the typical CT finding of Biliary cystadenoma?

Unilocular or multilocular cyst with fluid density, septa may calcify or enhance, may show upstream bile duct dilatation and perilesional THAD, no communication with bile ducts

What enhancement pattern is seen in haemangiomas?

Late arterial (peripheral nodular discontinuous enhancement), PV (centripetal (inward) fill-in), primovist (high flow haemangiomas show pseudo-washout)

What are some hepatocyte-specific contrast agents?

Gd (primovist and multihance), SPIO (susceptibility weighted), manganese-based

What are the MRI findings suggestive of FNH?

T1/T2 isointense with T2 bright central scar, arterial (early enhancement), PV (persistent enhancement), delayed (slight remaning enhancement remaining, central scar enhances), Primovist (takes up contrast)

What Nuclear medicine findings are suggestive of FNH?

Hot on Tc99m sulfur colloid & HIDA (due to Kupffer cells)

What are subtypes, risk factors, and prognosis of adenomas?

HNF1a (women, OCP, very low malignant risk), b-catenin (men, steroids, malignant risk 10%), inflammatory (NAFLD, bleeding risk). Multiple adenomas seen in von Gierke (glycogen storage disorder)

What are the CT findings suggestive of HCC?

Lobular contour, caudate enlargement, ascites, splenomegaly, varices, portal vein distension

What are the LIRADS major criteria diagnostic of HCC?

Non-rim arterial hyperenhancement, non-peripheral washout, enhancing pseudocapsule, >50% threshhold growth in 6 months

What are risk factors for HCC?

HBV (most common cause worldwide), HCV, alcohol, NASH, aflatoxins, haemochromatosis, a1AT, Wilson, PBC

What is the management for HCC?

Correlate with AFP levels, stage with Barcelona clinic liver cancer staging (performance status, Child-Pugh score, tumour extent). Options are resection, liver transplant, RFA/MWA, TACE, sorafenib, supportive care

How is RFA done?

High frequency probe needle placed under CT, generates an alternating current >60 degrees that damages local tissues

What is TACE?

Direct administration of chemo to HCC via catheter under DSA

Difference between Fibrolamellar HCC from conventional HCC?

Young adults (20-40), no association with cirrhosis/alcohol/HBV, no AFP, T2 dark non-enhancing central scar, can calcify, less aggressive, better prognosis with resection

What the risk factors for Angiosarcoma?

Thorotrast, arsenic, ionising radiation, vinyl chloride, haemochromatosis, NF1

What are some differential diagnosis for multiple liver lesions?

Neoplasia (lymphoma, epithelioid haemangioendothelioma), infection (abscesses, candidiasis, TB), sarcoidosis, peliosis

What are RECIST criteria?

Response evaluation criteria in solid tumours - rules to assess tumour burden of target lesions (up to 5 per organ and 10 total) to provide an objective assessment of response to therapy (complete response, partial response, stable disease, progressive disease)

What is the classification of Choledochal cyst?

Todani: 1 - fusiform CBD, 2 - CBD diverticulum, 3 - choledochocele, 4 - intra/extrahepatic, 5 - intrahepatic (Caroli)

What are the associations of PSC?

Ulcerative colitis, Sjogren, IgG4 disease

What are some of the associations of PBC?

Sjogren, scleroderma, RA, Raynaud, celiac, cholelithiasis, ILD, raised serum AMA

What are the risk factors of Gallbladder cancer?

Chronic cholecystitis, gallstones, FAP, IBD, porcelain gallbladder, polyps >1cm that are sessile/solitary, PSC, FHx, obesity, DM, Mirizzi

Describe the embryological development of the pancreatic ducts and relevance to divisum?

Normally the larger dorsal anlage fuses with the smaller ventral anlage to form one main pancreatic duct draining into the major papilla. In 10% they fail to fuse, and the dorsal (Santorini) duct drains into the small minor papilla, increasing risk of pancreatitis. The ventral (Wirsung) duct drains into the major papilla with the CBD (crossing duct sign)

What is the Revised Atlanta classification for pancreatitis?

Interstitial oedematous pancreatitis (acute peripancreatic fluid collection --> pseudocyst) vs acute necrotising pancreatitis (acute necrotic collection --> walled off necrosis)

What are other manifestations of IgG4 disease?

Hypophysitis, Reidel thyroiditis, sialadenitis, orbital pseudotumour, fibrosing mediastinitis, retroperitoneal fibrosis, IgG4 renal/cardiovascular/lung disease

What CT differences between adenocarcinoma and NET?

NETs are arterially enhancing, more commonly in the tail and have necrosis, haemorrhage and calcification. They are octreotide positive. Adenocarcinomas are more ill-defined, at the head

What are the precursor lesions for pancreatic adenocarcinoma?

Pancreatic intraepithelial neoplasia (PanIN, responsible for >90%), IPMN, mucinous cystic neoplasm

Subtypes and manifestations of Neuroendocrine pancreatic tumour?

Insulinoma (most common, hypoglycemia), gastrinoma (Zollinger-Ellison), glucagonoma (4D syndrome), VIPoma (WDHA), somatostatinoma (DM)

What are Syndromic associations of pancreatic NET?

MEN1, vHL, TS

What tests can differentiate between IPMN and other pancreatic cysts?

EUS and FNA. Amylase is high in pseudocyst and IPMN, but low in serous/mucinous cystadenoma

Describe the Pathology Serous cystic neoplasm:

60F, head, central calcifications, glycogen-rich, associated with vHL, benign

Difference between main and side IPMN:

Main (40-50yo, high malignant potential - 60%), side (50-60yo, head and uncinate process, communicates with duct, typically benign - 5% malignant)

Management of IPMN:

Surveillance MRCP in 6 months, then every 2 years (if <1cm), EUS in 3-6 months if 2-3cm

Ddx for splenic solid mass:

Lymphoma, angiosarcoma, mets, haemangioma, hamartoma, littoral cell angioma, SANT, PEComa

Ddx for splenic cystic mass:

Pseudocyst, true cyst, lymphangioma, abscess, hydatid (may calcify), haematoma, laceration

What are some Associations seen in Polysplenia?

Bilateral bilobed lungs, midline liver, non-cyanotic congenital heart disease, malrotation, gallbladder/renal agenesis, azygos continuation of IVC

What are some Associations seen in Asplenia?

Bilateral trilobed lungs, midline liver, cyanotic congenital heart disease (TAPVR), malrotation, gallbladder agenesis, horseshoe kidney, duplicated SVC

What is a common tool in investigating Splenosis?

Tc99m sulfur colloid or Tc99m heat damaged RBC scan

Other manifestations of MEN2?

Medullary thyroid cancer, parathyroid adenomas (2A), mucosal neuromas/Marfanoid habitus (2B). chr10

Where is Pheochromocytoma likely to be found?

From chromaffin cells of adrenal medulla, or anywhere along sympathetic chain including bladder and organ of Zuckerkandl

Washout protocol in adrenal Adenoma investigation:

Absolute washout (PV-delayed/PV-unenhanced) >60%, relative washout (PV-delayed/PV) >40%

what the common Primaries for adrenal Metastasis:

Lung, CRC, breast, pancreatic, renal, HCC

Common causes Haemorrhage to happen in adrenal

Sepsis (Waterhouse-Friderichsen syndrome in paeds - meningitis), DIC, steroids, anticoagulation, trauma, underlying tumour

Location within the kidney where AML is most likely to be?

Intraparenchymal (75%) or exophytic (25%)

Histopathology of AML?

Blood vessels (without elastic tissue), spindle muscle cells, adipose tissue

What are some of the RCC Subtypes?

Clear cell (75%, vHL, aggressive, T2 high), papillary (10%, transplant kidneys, multifocal, T2 low), chromophobe (5%, oncoctyoma/BHD), Xp11 translocation (paeds), collecting duct (aggressive), medullary (sickle cell)

What is risk factors leads RCC?

Smoking, CRF, dialysis, acquired renal cystic disease

Risk factors leads TCC?

Smoking, aniline dye, radiation, cyclophosphamide, schistosomiasis (more for SCC)

Ddx for bilateral enlarged kidneys:

Lymphoma, diabetic nephropathy, glomerulonephritis, vasculitis (GPA, IgA nephropathy), HIV nephropathy, SLE

Extrarenal manifestations of ADPKD?

Intracranial berry aneurysms, bicuspid aortic valve, aortic dissection, multiple biliary hamartomas

Progress in Renal papillary necrosis.

Early (papillary necrosis), progressive (multifocal strictures, hydronephrosis with no renal pelvic dilatation, mural thickening/enhancement), end-stage (progressive hydro/pyonephrosis, parenchymal thinning, dystrophic calcification, shrunken putty kidney, autonephrectomy)

Causes of Bilateral striated nephrogram:

HAMPA: hypotension/shock, acute tubular necrosis, medullary sponge kidney, pyelonephritis, ARPKD

Causes of Cortical nephrocalcinosis:

COAG: acute cortical necrosis (ischaemia, sepsis, toxins), oxalosis, Alport, chronic glomerulonephritis

Causes of Medullary nephrocalcinosis:

HAMHOP: hyperparathyroidism, renal tubular acidosis, medullary sponge kidney (paeds), hypercalcaemia, oxalosis, papillary necrosis

Classifications of Urethral injury:

Goldman: 1 - stretching, 2 - above urogenital diaphragm, 3 - membranous urethra at diaphragm, 4 - bladder neck, 5 - anterior urethra

Subtypes of Testicular cancer:

Germ cell (95%) - seminomas make up 50% of GCT. Sex cord stromal: Leydig (most common), Sertoli, juvenile granulosa cell, fibroma-thecoma

Ultrasound indicators for urgent surgical management of testicular injuries?

Devascularisation, disruption of tunica, swirl sign of torsion

Tumour markers in the testicles:

bHCG (embryonal, choriocarcinoma, mixed seminoma), AFP (yolk sac, embryonal), LDH (seminoma, marker of tumour burden)

Subtypes of Varicocele:

Primary (due to incompetent or congenitally absent valves in testicular vein, usually left sided) and secondary (due to compression from extrinsic mass, obstruction from thrombus, or splenorenal shunting)

Causes of pseudoachalasia:

Malignancy (gastric, oesophageal, lymphoma), central neuropathy, stricture (ischaemia, reflux), scleroderma, Chagas, diffuse oesophageal spasm

Features of benign vs malignant strictures:

Benign (smooth tapering, concentric narrowing) vs malignant (abrupt, asymmetric, eccentric, irregular nodular mucosa)

Symptoms and anatomy for the Zenker diverticulum:

Herniation of mucosa and submucosa through the Killian triangle/dehiscence which is a focal weakness in the hypopharynx between the inferior pharyngeal constrictor muscle and cricopharyngeus posteriorly Pulsion vs traction diverticulum?

Malignant vs benign features for Gastric ulcer:

Malignant: irregular, shallow, within lumen, gastric folds don't reach ulcer margin, Carman meniscus sign, greater curvature. Benign: smooth, deep, projects behind lumen, gastric folds reach ulcer margin, Hampton's line, lesser curvature/body/antrum

Findings Scleroderma in barum swallow:

Oesophagus: dilated distally, short length (fibrosis)Small bowel: massive dilatation, reduced peristalsis, hidebound bowel sign (crowding of valvulae conniventes, stack of coins), accordion sign, sacculations (mesenteric border)Large bowel: pseudosacculation, loss of haustration

Epidemiology of sigmoid vs caecal volvulus:

Sigmoid (60%, elderly with chronic constipation/neurological conditions), caecal (10%, younger 30-60yo with mobile peritoneal fixation, restriction from adhesions/mass/pregnancy)

How would you perform a gastric scintigraphy

Fast 4 hours, give Tc-99m sulfur colloid radiolabelled egg albumin as a sandwich, can also give a liquid component (In111 DTPA), acquire images with a gamma camera, initially dynamically then at intervals for 1-3 hours. Measure half emptying time

Causes of Bowel ischaemia:

Arterial occlusion, venous occlusion, non-occlusive (NOMI), shock, vasculitis

Organsims leads Infectious colitis:

Bacterial (shigella, salmonella, yersinia, campylobacter, staph, E. coli, C. diff), TB, fungal, viral (CMV), parasitic (amoebiasis, schistosomiasis). Immunocompromised (TB, CMV)

Hall marks of Crohn's vs UC:

Crohn’s: transmural, increased thickness, skip lesions, string-sign, creeping fat, smoking a risk factor, crypt abscesses and non-caseating granulomas, complicated by abscesses/fistula/stricturesUC: more associated with PSC, involves rectum, lead pipe sign, open ileocecal valve, pseudopolyps, complicated by toxic megacolon and cancer

Classification Perianal fistula:

1 - simple linear intersphencteric, 2 - intersphincteric with abscess or secondary tract, 3 - transsphincteric, 4 - transsphincteric with abscess or secondary tract, 5 - supralevator and translevator extension

Ddx Appendiceal mucocele:

Abscess, carcinoid (most common appendiceal tumour - always benign), appendiceal mucinous neoplasm (mucinous cystadenoma/cystadenocarcinoma)

Types Gastric adenocarcinoma:

Intestinal (mass) vs diffuse (linitis plastica)

Subtypes of cancers for oesophagus::

SCC (upper), adenocarcinoma (lower), mucoepidermoid, adenoid cystic, leiomyosarcoma, lymphoma

Hamatomatous polyposis syndromes?

Juvenile polyposis (pAVM), Peutz-Jeghers (testicular sex cord tumours, colon/pancreatic/breast/lung/ovarian cancer), Cowden (breast/thyroid cancer, Lhermitte Duclos), Cronkhite Canada (watery diarrhoea)

contraindications for CT colonography?

Acute inflammatory conditions (diverticulitis, IBD), recent abdominopelvic surgery, pregnancy

FAP vs HNPCC?

FAP: APC mutation chr5, cancer before 30 years, variants (Gardner - osteomas, desmoid, epidermoid, dentigerous cyst, papillary thyroid cancer; Turcot - medulloblastoma/glioblastoma)HNPCC (Lynch syndrome): DNA mismatch repair, cancers in the ovary, ureter, endometrium, brain, bowel, liver, pancreatic

most common site for Mesenteric haematoma:

lymphoma, recent surgery, inflammatory (retropertioneal fibrosis, IgG4 disease)

Findings:

Enhancing thickened peritoneum, ascites, peritoneal calcification, lymphadenopathyCauses (Peritoneal dialysis, peritoneovenous/VP shunts, wet TB, sarcoidosis, GI/ovarian malignancy).

Features of inoperable cancer:

Anatomical (coeliac/hepatic/SMA >180 deg contact, SMV/PV >180 deg contact or narrowing/occlusion exceeding inferior duodenal border, metastases), biological (CA19-9 >500), conditional (ECOG >1)

Why do carcinoids cause bowel obstruction?:

Due to the desmoplastic reaction and venous occlusion

Tumours that are FDG PET cold:

Carcinoid, low grade pulmonary adenocarcinoma (AIS), RCC, prostate, mucinous cancer

What cells do carcinoids arise from?

APUD enterochromaffin/Kulchitsky cells (in intestinal crypts of Lieberkuhn)

Ddx for retroperitoneal mass:

Lymphoma, metastases, sarcoma (lipo/leiomyo/UPS - in order of frequency), histocytoses, neurogenic tumour (schwannoma, paraganglioma, ganglioneuroma, plexiform neurofibroma), germ cell tumour (usually from testis), lymphatic malformation, desmoid

What is the transport medium for flow cytometry for

Normal saline or RPMI (viral medium)

What is the hallmark histopathological feature of Rosai Dorfman?

Macrophage ingesting multiple lymphocytes

Ddx for Retroperitoneal fibrosis:

Retroperitoneal fibrosis (medialisation of ureters), Erdheim Chester (coated aorta, hairy kidneys), lymphoma (anterior displacement of aorta)

Causes of perforated viscous:

Trauma, ERCP, peptic ulcer, cancer, diverticulitis, ischaemia, iatrogenic, Valsalva, steroids

Name 3 histiocytic disorders

LCH, Erdheim-Chester, Rosai-Dorfman

Types of endoleak:

1 - graft attachment site (urgent), 2 - branch vessel (most common), 3 - graft defect (urgent), 4 - graft porosity, 5 - endotension

Pathology:

AAA eroding into duodenum due to long-standing pressure, often along with mycotic aneurysms

List other medium and small vessel vasculitides::

Medium ANCA+ (GPA, EGPA), medium ANCA- (PAN, Kawasaki), small ANCA+ (microscopic polyangiitis), small ANCA- (IgA vasculitis, Behcet, Buerger)

Other abdominal vascular compression syndromes

Nutcracker (LRV compressed between SMA & aorta), SMA, median arcuate ligament syndromes

Ddx for vascular tumours:

Leiomyosarcoma, haemangioma, haemangioendothelioma, lymphangioma, Kaposi sarcoma