Intravascular ultrasonography for assessment of portal vein invasion by pancreatic carcinoma.

Intravascular ultrasonography (IVUS) was performed to diagnose portal vein invasion by pancreatic carcinoma. In 55 patients with pancreatic carcinoma, the intravascular ultrasonographic catheter was introduced during operation through a branch of the superior mesenteric vein into the intrahepatic portal vein. The catheter was gradually withdrawn, and the cross-sectional images of the area under investigation were recorded. Altogether 45 patients underwent resection, and 34 underwent combined resection of the portal vein. The IVUS findings were compared with the histologic findings of the resected specimen, preoperative computed tomography (CT), and arterial portogram. The wall of the portal vein was visualized as an echogenic band with a thickness of 0.5 to 1.0 mm. A subtle portal vein invasion can be detected by observing this portal vein wall. For the diagnosis of portal vein invasion, the sensitivity, specificity, and overall accuracy of IVUS were 99.6%, 92.3%, and 94. 5%, respectively. The equivalent values for portography were 79.3%, 61.5%, and 70.9%; and those for CT were 82.1%, 74.1%, and 78.1%. IVUS provides more valuable and accurate information on portal vein invasion by pancreatic carcinoma than either CT or portography.