Complications of orthotopic liver transplantation: spectrum of findings with helical CT

Orthotopic liver transplantation has become the treatment of choice for patients with end-stage nonmalignant liver disease. The surgical techniques and immunosuppressive therapy for this procedure have improved considerably. Nevertheless, there are still significant complications, particularly those of vascular origin, which can lead to graft failure and require retransplantation unless prompt treatment is instituted. These complications include arterial and venous thrombosis and stenosis; arterial pseudoaneurysm; biliary leakage, stricture, and obstruction; liver ischemia, infarction, and abscess; fluid collections and hematomas; lymphoproliferative disorders; recurrent tumors; hepatitis C virus infection; and splenic infarction. Since the clinical presentation of posttransplantation complications is frequently nonspecific and varies widely, imaging studies are critical for early diagnosis. Helical computed tomography (CT) is a valuable complement to ultrasonography (US) in the postoperative period and is a safe, accurate, and noninvasive method of demonstrating hepatic vessels (hepatic artery, portal vein, hepatic veins, and inferior vena cava) and evaluating nonvascular complications (in the hepatic parenchyma and bile duct abnormalities) and extrahepatic tissues. Knowledge and early recognition of these complications is essential for graft salvage, and CT can provide valuable information, particularly for patients with indeterminate US results or in whom US examination is difficult.

Arteriovenous fistula secondary to iliac mycotic aneurysm: helical CT findings

We describe the case of a 59-year-old man who presented a mycotic aneurysm of the common right iliac artery due to Streptococcus agalactiae and developed an arteriovenous fistula within the inferior vena cava secondary to spontaneous rupture of the aneurysm. The clinical syndrome, helical computed tomographic, and angiographic findings are described and discussed.

Intrahepatic arterioportal shunt: helical CT findings

The purpose of this study was to characterize the appearance of intrahepatic arterioportal shunts (APS) on two-phase helical CT, with emphasis on the importance of the hepatic arterial-dominant phase (HAP) to demonstrate perfusion disorders. We review eight cases of APS diagnosed by helical CT in our institution from January 1996 to March 1997 and describe the CT findings that established diagnosis. Five of them were confirmed by angiography. In seven (87. 5 %) cases of APS we found early enhancement of the peripheral portal branches during the HAP of helical CT, whereas the superior mesenteric and splenic veins remained unenhanced. In five (62.5 %) cases of APS, transient, peripheral, triangular parenchymal enhancement was depicted during the HAP of helical CT; in four of these cases there was associated early enhancement of the portal branches. Helical CT can show perfusion alterations that might remain undiagnosed with conventional CT. An understanding of the hemodynamic changes that occur in APS can help in the interpretation of focal transient hepatic parenchymal enhancement and to differentiate APS from hypervascular tumors. We believe that the helical CT findings described herein are characteristic enough to suggest the diagnosis of APS.

Renal trauma in occult ureteropelvic junction obstruction: CT findings

The aim of this study was to present CT findings of occult ureteropelvic junction obstruction in patients with renal trauma and to describe the clinical signs and singular CT features that are characteristically observed with trauma and are relevant to management of these patients. We retrospectively reviewed 82 helical CT studies in patients with renal trauma referred to our institution. We found 13 cases of occult preexisting renal pathology, six of which were occult ureteropelvic junction obstructions. The clinical presentation, radiologic findings of trauma according to the Federle classification, and CT findings of obstructed ureteropelvic junction are presented. We found three category-I lesions (one in horseshoe kidney), two of them treated with nephrostomy because of increased ureteropelvic junction obstruction due to pelvic clots; two category-II lesions (parenchymal and renal pelvis lacerations) that had presented only with microhematuria; and one category-IV lesion (pelvic laceration alone). Pelvic extension was demonstrated in all the cases with perirenal collections. The CT studies in all the cases with suspected ureteropelvic junction obstruction showed decreased parenchymal thickness and enhancement, and dilatation of the renal pelvis and calyx, with a normal ureter. Computed tomography can provide information to confidently diagnose underlying ureteropelvic junction obstruction in renal trauma, categorize the traumatic injury (at times clinically silent) and facilitate proper management according to the singularities observed, such us rupture of the renal pelvis alone (Federle category IV) and increasing ureteropelvic obstruction due to clots which can be decompressed by nephrostomy.

Small bowel obstruction secondary to bezoar: CT diagnosis

Two cases of small bowel obstruction secondary to phytobezoar diagnosed by computed tomography (CT) and confirmed at surgery are presented. CT findings were dilated intestinal loops and an intraluminal mass with air bubbles retained in its interstices, resulting in a mottled appearance. We propose that definite diagnosis of small bowel bezoar can be made on the basis of these CT findings.

Duodenal schwannoma causing gastrointestinal bleeding: helical CT findings

Neurogenic tumors of the small intestine are extremely rare and represent an unusual cause of gastrointestinal hemorrhage. We present a case of schwannoma of the fourth portion of the duodenum demonstrated by helical computed tomography. Multiplanar reconstructions showed a hypervascular tumor arising from the inferior wall of the duodenum. The use of water as oral contrast agent instead of iodinated contrast permitted a better visualization of the intact mucosa and differentiated a hypervascular tumor from hypodense gastrointestinal content.

CT evaluation of underlying cause in spontaneous subcapsular and perirenal hemorrhage

We evaluated the CT scans of 13 patients with spontaneous subcapsular or perinephric hemorrhage (SPH) associated with these underlying causes: 4 angiomyolipomas, 2 renal cell carcinomas, 1 renal metastatic malignant melanoma, 1 ruptured renal artery aneurysm, 1 adrenal myelolipoma, 1 ruptured renal abscess, 2 ruptured hemorrhagic cysts, and 1 patient with undiagnosed coagulation disorder. Our objective was to ascertain whether an underlying cause of SPH was identifiable by CT, and to determine the extension of the hematomas. Computed tomography identified the hematoma in all 13 cases (sensitivity 100 %). In all 12 cases in which there was a renal or adrenal anatomic lesion, the underlying cause was identified with CT (100 %), with correct diagnosis in 11 cases (91.6 %). The case in which no lesion was identified was the undiagnosed coagulation disorder. We conclude that CT is a useful technique for the initial evaluation of SPH, permitting diagnosis of hemorrhage and identification of the underlying cause.