Detecting hepatic lesions: the added utility of CT liver window settings.

PURPOSE: To prospectively evaluate the utility of adding computed tomographic (CT) liver windows to conventional soft-tissue windows for the detection of hepatic disease. MATERIALS AND METHODS: One of four radiologists experienced in abdominal imaging interpreted 1,175 consecutive abdominal CT scans from one institution. Hepatic images were first interpreted by using standard soft-tissue windows. The number of lesions and confidence in lesion detection were recorded. The liver-window images were then interpreted in conjunction with the soft-tissue-window images, and the number of lesions and confidence in detection were recorded again. The proportion of patients in whom additional lesions were found by using liver windows was determined. RESULTS: On soft-tissue-window and liver-window scans interpreted together, 869 (74%) patients had no hepatic lesions. Thirty-six (3.1%) patients had new lesions seen with the addition of liver windows. Twelve of these 36 patients had no lesions seen on soft-tissue-window scans. Twenty-six of the 36 patients with additional lesions seen had a history of neoplasm. There was a change in diagnosis in 1.7% of the patients with the addition of liver windows and a change in recommendation for follow-up in 0.85%. CONCLUSION: Routine interpretation of liver-window scans for all abdominal CT scans has limited added utility in detecting hepatic disease.

New techniques of ultrasound and color Doppler in the prospective evaluation of acute renal obstruction. Do they replace the intravenous urogram?

BACKGROUND: The intravenous urogram has long been the primary imaging modality in assessing acute renal obstruction. Newer ultrasound (US) techniques including pulsed and color Doppler allow the physiology of the urinary system to be interrogated via the resistive indices and ureteral jets. We sought to determine whether these new techniques would improve the ability of ultrasound to assess the presence of renal obstruction and replace the intravenous urogram in assessing acute ureteral obstruction. METHODS: 32 patients suspected of having acute renal obstruction were evaluated with US and a KUB. A prospective diagnosis of complete, partial, or no obstruction was made. An intravenous urogram (IVU) was then performed as the "gold standard" for comparison. RESULTS: Complete obstruction was correctly identified by the absence of a ureteral jet with no false negative studies. Using our ultrasound KUB protocol, partial obstruction was correctly identified in 77% of patients. All nonobstructed patients were correctly diagnosed. The overall sensitivity of combined ultrasound and KUB analysis was 84%, specificity 85%, and accuracy 87.5%. CONCLUSION: Contemporary ultrasound employing pulsed and color Doppler is tedious and requires expertise not always available. Results with the intravenous urogram are more sensitive than specific. Unless contrast material is contraindicated, acute obstruction is best evaluated with intravenous urography.

Cavernous hemangioma of the liver: role of percutaneous biopsy.

Fifteen patients with liver masses detected with imaging were strongly considered clinically to have malignant disease. In each case, the possibility of a hepatic cavernous hemangioma was raised upon review of the images. With use of a 20-gauge Franseen needle, a percutaneous hepatic biopsy was performed in all 15 cases, and the diagnosis of cavernous hemangioma was confirmed. There were no complications from the biopsy. Twelve biopsies were performed on an outpatient basis. On the basis of the biopsy results, the care and treatment of each patient were significantly altered. When imaging data are not sufficient to determine that a liver mass is benign, even if the possibility of cavernous hemangioma is entertained, a percutaneous biopsy can be safely performed and can yield a specific histologic diagnosis.