Technetium-99m MAG3, a comparison with iodine-123 and iodine-131 orthoiodohippurate, in patients with renal disorders.

A Phase I study in 12 patients with renal disorders compared the simultaneous clearances of 99mTc-labeled mercaptoacetyltriglycine (MAG3) and 131I-labeled orthoiodohippurate (OIH). The ratio of MAG3 to OIH clearance was 0.61 +/- 0.08 as a result of its smaller volume of distribution, ratio 0.65 +/- 0.09, for the clearance half-lives were similar, ratio 1.09 +/- 0.12. A Phase II study performed serially in 20 patients with equal doses of [99mTc]MAG3 and [123I]OIH gave images of equal quality. The relative renal functions were highly correlated (r = 0.97, p less than 0.001) and transit time analyses gave good correlations: parenchymal transit time index r = 0.81, p less than 0.05. We conclude that [99mTc]MAG3 has some advantages over [99mTc]DTPA and is a suitable replacement for [123I]hippuran in routine renal imaging, relative function, and transit time studies, but not for the accurate estimation of the renal plasma flow.

Clinical experience with 99mTc-MAG3, mercaptoacetyltriglycine, and a comparison with 99mTc-DTPA.

The preparation, application and clinical usage of 99mTc-mercaptoacetyltriglycine, MAG3, a tubular secreted compound, is described in the first 225 patients in a phase III study. Image quality, relative renal function, and renal transit times were compared with a 4 fold greater administered activity of 99mTc-DTPA in 11 patients. Correlation coefficients of 0.94 for relative function, 0.83 for parenchymal transit time index and 0.82 for whole kidney transit time index were found. Frusemide responses were similar. 99mTc-MAG3 is an efficacious radiopharmaceutical for routine renal radionuclide studies, giving excellent image quality in patients with hypertension, poor renal function, obstructive nephropathy or a renal transplant.