The term portal cavernoma cholangiopathy refers to the biliary tract abnormalities that accompany extrahepatic portal vein obstruction (EHPVO) and subsequent cavernous transformation of the portal vein. EHPVO is a primary vascular disorder of the portal vein in children and adults manifested by longstanding thrombosis of the main portal vein. Nearly all patients with EHPVO have manifestations of portal cavernoma cholangiopathy, such as extrinsic indentation on the bile duct and mild bile duct narrowing, but the majority are asymptomatic. However, progressive portal cavernoma cholangiopathy may lead to severe complications, including secondary biliary cirrhosis. A spectrum of changes is seen radiologically in the setting of portal cavernoma cholangiopathy, including extrinsic indentation of the bile ducts, bile duct stricturing, bile duct wall thickening, angulation and displacement of the extrahepatic bile duct, cholelithiasis, choledocholithiasis, and hepatolithiasis. Radiologists must be aware of this disorder in order to provide appropriate imaging evaluation and interpretation, to facilitate appropriate treatment and to distinguish this entity from its potential radiologic mimics.

Urinary diversion is a surgical technique to redirect the stream of urine, most often after cystectomy. Cystectomy may be performed both for benign and for malignant conditions. Bladder cancer is the most common indication for cystectomy, and most patients who undergo radical cystectomy and urinary diversion have muscle-invasive or high-risk non-muscle-invasive bladder cancer. There are two major surgical approaches for urinary diversions performed after radical cystectomy: continent and incontinent diversions. For incontinent urinary diversions, a cutaneous ostomy is used for continuous urine drainage (eg, ileal conduit). With a continent diversion procedure, the patient may void through the native urethra or self-catheterize through a surgically created stoma. The goals of imaging after urinary diversion are to assess postoperative anatomy, detect postoperative complications, evaluate for residual or recurrent tumor and metastatic disease, and monitor for upper tract distention and/or deterioration. Multiple imaging modalities and techniques may be used to evaluate urinary diversions, including computed tomographic and magnetic resonance urography, intravenous pyelography, ultrasonography, pouchography, loopography, and nephrostomy studies. Knowledge of the expected postoperative appearance after urinary diversions and potential postoperative complications is crucial because many complications may be clinically silent. Radiologists must be able to recognize the expected postoperative appearance as well as complications to facilitate appropriate diagnosis and treatment of patients after cystectomy and urinary diversion. (©)RSNA, 2016.

A variety of entities may mimic drainable abscesses. This can lead to misdiagnosis of these entities, unnecessary percutaneous placement of a pigtail drainage catheter, other complications, and delay in appropriate treatment of the patient. Types of entities that may mimic drainable abscesses include neoplasms (lymphoma, gallbladder cancer, gastrointestinal stromal tumor, ovarian cancer, mesenteric fibromatosis, ruptured mature cystic teratoma, recurrent malignancy in a surgical bed), ischemia/infarction (liquefactive infarction of the spleen, infarcted splenule), diverticula (calyceal, Meckel, and giant colonic diverticula), and congenital variants (obstructed duplicated collecting system). Postoperative changes, including expected anatomy after urinary diversion or Roux-en-Y gastric bypass and small bowel resection, may also pose a diagnostic challenge. Nonpyogenic infections (Mycobacterium tuberculosis, Mycobacterium avium complex, echinococcal cysts) and inflammatory conditions such as xanthogranulomatous pyelonephritis and gossypiboma could also be misinterpreted as drainable fluid collections. Appropriate recognition of these entities is essential for optimal patient care. This article exposes radiologists to a variety of entities for which percutaneous drainage may be requested, but is not indicated, and highlights important imaging findings associated with these entities to facilitate greater diagnostic accuracy and treatment in their practice. RSNA, 2018.