Experimental and clinical studies on CT diagnosis of pancreas cancer by intra-venous bolus injection of contrast medium

CT scan with intravennus bolus injection of contrast medium (CT-Angio) was studied to improve the diagnostic ability for pancreatic carcinoma. CT scan planning of this procedure was estimated by intravenous bolus injection of sup(99m)Tc pertechnetate, the time-activity curve of which obtained corresponding to the pancreas indicated, that the optimal scan timing was 20 seconds after the beginning of the injection. Subsequently, CT-Angio was performed in 24 patients with proved pancreatic carcinoma, with an injection of 50 - 60 ml of 65% Angiografin at a rate of 5ml/sec. And the diagnostic accuracy of this procedure was evaluated comparing to that of plain-CT, conventional enhancement CT(CE-CT), and angiography. The difference of attenuation value between tumor and pancreas parenchyma was measured using ROI cursor which demonstrated 3 H.U. (mean) in plain CT, 32.2 H.U. (mean) in CE-CT, and 55.4 H.U. (mean) in CT-Angio respectively. In addition to this, the vessels adjacent to the pancreas, including superior mesenteric, splenic, and portal vein were also highly enhanced, demonstrating the irregularity or occluation when tumor invasion was present. And this indicated the useful role of CT-Angio in the diagnosis of the vascular involvement of pancreas carcinoma. CT-Angio was experimentally detectable the tumor as small as 2 cm in dog pancreas, which prepared with intraparenchymal injection of cyanoacrylate through a fine needle. From these results; we considered CT-Angio is essential not only in the detection of early pancreatic carcinoma, but also in the diagnosis of its tumor-extent. (author)