Metastatic Melanoma
Most common sites of metastases: Skin, lymph nodes (75%), lung (70%), liver (58%), CNS (54%), GI tract (40%) Most common sites in abdomen: Liver and small bowel • Melanoma metastases are…
Gallstones and Sludge
Choledocholithiasis: Stones within common bile duct (CBD) • Sludge: Suspension of particulate material/bile in gallbladder (GB) IMAGING • Gallstones Ultrasound: Brightly echogenic nodule with marked posterior acoustic shadowing – Mobile with “twinkling” on…
Budd-Chiari Syndrome
May simulate a large neoplasm within caudate lobe • Intrahepatic and systemic venous collaterals bypass obstructed hepatic veins and IVC Spider web pattern of hepatic venous collaterals on CT, MR, angiography…
Pancreatic IPMN
Well-defined cystic lesion with variable morphology: Unilocular, multicystic, or tubular Communication with adjacent main pancreatic duct is key to diagnosis (may be more visible on MR than CT) Dilatation of…
Gastric Carcinoma
Polypoid or circumferential mass with no peristalsis through lesion • Best imaging tool Double-contrast upper GI series, CECT, EUS TOP DIFFERENTIAL DIAGNOSES • Normal variant • Benign gastric (peptic) ulcer • Gastritis • Gastric metastases…
Diverticulitis
Multiple colonic diverticula and colonic wall thickening Inflammation of pericolonic fat (stranding) Thickened base of sigmoid mesocolon Engorged mesocolic blood vessels “Microperforation”: Small bubbles of pericolonic gas • More complicated diverticulitis More…
Hepatic Cavernous Hemangioma
Arterial phase: Early peripheral, nodular or globular, discontinuous enhancement • Small hemangiomas (capillary): < 2 cm Arterial and venous phases: Homogeneous enhancement (flash-filling) • Typical hemangiomas: 2-10 cm in diameter Venous phase:…
Mucinous Cystic Pancreatic Tumor
“Macrocystic” pattern: Few (< 6) macrocystic locules, which are relatively large (> 2 cm) Usually of simple fluid attenuation, but may be mildly hyperdense due to hemorrhage or protein Frequent…
Focal Nodular Hyperplasia
Hypodense or isodense to normal liver • Delayed scans Mass: Isodense to normal liver Central scar: Hyperdense or hyperintense (due to fibrous tissue) • Gadoxetate-enhanced MR Most specific test to diagnose FNH…
Hepatic Schistosomiasis
Periportal fibrotic bands and widened fissures Capsular calcification (parallel or perpendicular to liver surface) • Portal hypertension in advanced disease Splenomegaly and varices • US: Bull’s-eye lesion: Represents anechoic portal vein surrounded…
