Quantitative static and dynamic renal scintigraphy with diuresis stimulation in renovascular hypertension

The results of computer-assisted static and dynamic renal scintigraphy in 57 patients with renovascular hypertension (RVH) and 23 patients with essential hypertension (EH) are presented. The following parameters were quantified: renal size (RS), count density (CD), relative unilateral renal clearance (RRC), mean parenchymal transit time (PTT), difference of time-to-peak of activity (tmaxd) to stenosed minus non-stenosed side, effect of frusemide (FE) and renal parenchymal radionuclide retention (RI). Among 57 stenosed renal arteries we detected 54 (true-positive cases) and missed three (false-negative cases); among 23 patients with EH and no significant haemodynamic renal artery stenosis, we found 21 cases correctly negative and two patients falsely positive. These data yielded a sensitivity of 95% and a specificity of 92%. The quantification of renal radionuclide studies in renal artery stenoses minimizes false-positive results and increases their specificity. This study shows that, because of its sensitivity, quantitative renal scintigraphy reliably allows the assessment of the functional haemodynamic effects of a renovascular lesion (significant stenosis) in the diagnostic work-up and during follow-up after surgical reconstruction or percutaneous transluminal angioplasty (PTA). The evaluation of renal function is in general greatly supported by the quantitative parameters, yet particularly after medication with converting enzyme inhibitors and after intervention.