Arterial Stimulation with Venous Sampling
The principle of this test is the same as a normal venous sampling test except that the organ of interested is stimulated with a substance and the organ's response is monitored. The test involves a radiologist inserting a tiny tube into the vein draining the organ of interest. Substances can then be injected specifically into the organ. Specific substances can be used that only stimulate abnormal tissue. Any hormone produced can then be detected by blood samples taken from the veins, indicating the presence of abnormal tissue. An example is in the diagnosis of insulinomas. Calcium is injected into the feeding arteries of the pancreas. This causes a release of insulin from an insulinoma, which can be detected in blood samples taken from the veins. Normal pancreas tissues will not react to the calcium.