CT appearance of primary pancreatic lymphoma

Primary lymphoma of the pancreas is a rare neoplasm that may resemble pancreatic carcinoma on CT scans. Two cases with CT findings are presented.     

Diagnosis and treatment of iatrogenic femoral artery pseudoaneurysms

Color Doppler is the procedure of choice for the diagnosis of iatrogenic femoral artery pseudoaneurysms. Although surgery is still necessary in a limited number of patients, most can be treated with ultrasound-guided thrombin injection. Success exceeds 90% and complications are much lower than surgery. Although rare, the major complication is embolization into the femoral artery. This can be minimized by using as little thrombin as possible, and by avoiding small pseudoaneurysms with short necks.     

Gallbladder sludge formation after bone marrow transplant: Sonographic observations

We prospectively studied 12 patients before and after bone marrow transplantation (BMT) with serial sonography to evaluate gallbladder sludge formation. Patients were studied on four separate occasions to assess the gallbladder for sludge and stones: prior to BMT and conditioning chemoradiation, and on days 3, 13, and 28 after BMT. During two of the sonographic studies, gallbladder volume measurements were made before and after administration of cholecystokinin octapeptide (CCK-OP) and the ejection fraction (EF) was calculated. Medical records were reviewed for symptoms of cholecystitis, narcotic use, and dietary intake. Sludge and/or stones developed in eight of 12 patients (67%), and in four patients sludge was observed by day 3 post-BMT. Ejection fraction was normal (>50%) pre-BMT in six of the eight patients who developed sludge, and in four of these six post-BMT. Furthermore, five of the eight patients developed sludge and/or stones in the absence of fasting and/or narcotic use. We conclude that gallbladder sludge develops frequently and early in BMT patients and may resolve or progress to stone formation. We did not demonstrate a relationship between impaired contractility and the development of sludge and/or stones, nor did we find a strong association between sludge formation and conditions presumed to cause gallbladder stasis, such as narcotic use and fasting. These findings suggest that other factors apart from impaired gallbladder contractility may play a role in the formation of sludge in the BMT patient.     

Differentiating pelvic veins and enlarged lymph nodes: optimal CT techniques

A study was done to find the best technique of administering contrast material intravenously to enable differentiation of pelvic veins and enlarged lymph nodes on computed tomographic (CT) scans. Seventy-eight patients with suspected pelvic malignancies were evaluated with CT. After precontrast scans were obtained at a selected pelvic level, 150 mL of contrast material was injected as a two-phase bolus; images were obtained at the same level 1.5, 3, 5, and 7 minutes after initiation of the bolus. Mean pelvic venous enhancement was maximal between 3 and 7 minutes in all the patients. Venous attenuation changes did not correlate with the presence of cardiac or peripheral vascular disease, but there was significantly less enhancement in patients with diabetes mellitus. The time of maximum vein enhancement begins at 3 minutes and continues for at least 4 minutes. A delayed technique of scanning the pelvis may be preferable to rapid scanning to optimize enhancement of the pelvic veins.     

Gangrenous cholecystitis: new observations on sonography.

We studied 25 patients with gangrenous cholecystitis and observed a new sonographic finding--striated thickening of the gallbladder wall--and three patterns of pericholecystic fluid collections. Heterogeneous thickening of the gallbladder wall was characterized by either multiple striations (alternating hypoechoic and hyperechoic layers) or irregular mass-like protrusions projecting into the gallbladder lumen. We observed striated thickening far more frequently (in 10 of 25 patients) than other findings reported previously as being associated with gangrenous cholecystitis, such as intraluminal membranes (1 in 25 patients) and masslike protrusions into the gallbladder lumen (1 in 25 patients). Although the sensitivity and specificity of this finding cannot be determined by our study, we believe that mural striations in cases of acute cholecystitis should raise the question of gangrenous changes. Additionally, we found that two subtypes of pericholecystic fluid collections (types II and III) were associated with gallbladder wall perforation and abscess formation more frequently than type I collections.     

CT manifestation of neutron radiotherapy-induced changes in lung

Sixty-nine chest CT studies of 36 patients with lung cancer were obtained at various times (21 to 649 days) following completion of fast neutron radiotherapy. Multiple scans (2 to 7) were available in 16 cases. Fractionated neutron radiotherapy was delivered over four to seven weeks to a total dose of 60 to 67 Gy photon equivalent. Parenchymal change within the lung was noted in 43% by 12 weeks, in 91% between 12 and 24 weeks, and in 100% after 24 weeks. Three different patterns of lung parenchymal change were evident. Ectatic air-filled bronchi were observed in more than 50% after 24 weeks. Mediastinal shift and thoracic shrinkage were demonstrated in six and three cases, respectively. Serial CT scans revealed that lung parenchymal changes usually became stable or shrunk after 36 weeks. The possible effect of chemotherapy (mitomycin-C, vinblastin and cis-platinum), in 19 of these patients is also discussed.