The role and rationale of nuclear medicine procedures in the differential diagnosis of renovascular hypertension.

The use of radionuclides in the differential diagnosis of renovascular hypertension has gone through many periods of enthusiasm and of disappointment. Regardless of the problems with the routine renogram, the availability of gamma camera renal evaluation makes possible meaningful preintervention of screening. The use of the test as a follow-up procedure is an extremely important but often overlooked application of radionuclides in the evaluation of renovascular hypertension. The radionuclide technique is a sensitive and accurate method of evaluating the results of percutaneous angioplasty or surgery or renal function in the affected kidney of patients with renovascular disease. A major change in our approach to the nuclear medicine diagnosis of renovascular hypertension has been the introduction of captopril renography. Although there is still a great deal of work to be done and many investigators are actively studying captopril renography, the potential of the test is clear. Captopril renography should include a baseline renogram, followed by the administration of 25 mg of captopril and a repeat study. Specificity and sensitivity data on this test probably will not be available for several years, but preliminary results are encouraging enough to justify routine use at this time in clinics in which screening for renovascular hypertension is carried out.