The Investigation Of Clinical Value Of Intra-arterial Calcium Stimulation Test In Preoperative Localization Of Insulinoma

Objective : To evaluate the clinical value of intra-arterial calcium stimulation and venous sampling (ASVS) for localization of insulinoma preoperatively. Methods: Eight patients with clinically proved insulinoma underwent ASVS test ,proper hepatic artery(PHA),gastroduodenal artery(GDA),superior mensenteric artery(SMA),proximal and distal splenic arteries(SAP and SAD) were selectively catheterized for stimulation by rapid injection of calcium gluconate. Blood was sampled through hepatic vein before and 30, 60, 90, 120, 180 s after stimulation for gauging the insulin levels.A gap of 15 minutes between every two stimulations was preserved.The tumor would be regionalized in the corresponding area if the peak value of insulin after stimulations in certain artery reached or higher than 4 times of the baseline level.If two or above arteries reached or higher than 4 times of the baseline level, The tumor site was considered to be at the corresponding area supplied with certain artery stimulated showing the peak ratio of insulin to the baseline. Results: Eight patients didn't have adverse reactions during ASVS and applications after ASVS.Six solitary insulinomas with the size as 0.7-1.6cm were diagnosed after surgery,two patients were lost.The results of ASVS were identical to the final diagnosis in 5 cases,the accuracy of ASVS was 83.3%, demonstrating the superiority over BUS( 33.3%) , CT( 75%) , MRI( 80%) .Conclusion: ASVS is an accurate and safe technique to localize insulinomas preoperatively, especially for occult insulinomas with negative or discrepancy findings in imaging studies.