Small nodular lesions of the pancreas : differential diagnosis with ultrasound angiography

Abstract

Ultrasound angiography (USAG), sonographic imaging of the blood flow in an organ or tissue obtained by carbon dioxide infusion into the supplying artery, was performed on 28 pancreatic nodular lesions less than 3 cm in diameter. The hemodynamics of tumors observed with USAG were divided into three groups : hypovascular, isovascular, and hypervascular, compared with the adjacent pancreatic tissue. Most of hypovascular nodules were duct cell carcinoma (sensitivity 94.1%, specificity 90.4%), while isovascular lesion was the characteristic of inflammatory masses (sensitivity 100%, specificity 95.8%). Hypervascular cases included all of the mucin producing tumors and islet cell tumors but only one case of duct cell carcinoma. So you can almost exclude duct cell carcinoma as an diagnosis in vascular rich tumors (negative predictive value 83.3%).
These results were compared with those on conventional x-ray angiograms and incremental CT scans. Ultrasound angiography enabled us to detect more slight differences of tumor vascularity than the other modalities. Thus we conclude that USAG can be a useful diagnostic aid in small mass lesions of the pancreas.