Gamma Camera Renography with 99 Tc m -MDP and 131 I-Hippuran

Abstract

Nineteen patients with urologic disorders referred to bone scintigraphy were evaluated with a dual radioisotope technique using simultaneous injection of ⁹⁹Tc^m-MDP and ¹³¹I-Hippuran. The MDP and Hippuran renograms showed in general the same pattern and there was no difference between the kidney function determined with the two radionuclides. The peak of the MDP curves occurred later and was less distinct than that of the Hippuran curves. The residual activity of the kidneys 20 min after the injection was higher on the MDP renograms compared with the Hippuran renograms. The early sequential MDP images were superior in quality to the Hippuran images and to the renal images obtained at bone scintigraphy. The early MDP images correlated well with the findings at urography performed in 12 patients, as all cases of radiologically diagnosed hydronephrosis, reduction of renal parenchyma and renal mass lesions became demonstrated. Renal calculi were only diagnosed at urography. In conclusion, MDP cannot replace Hippuran as a renal radionuclide agent, mainly due to its lower extraction ratio and the high bone uptake. However, an increased use of early dynamic renal imaging is recommended in urologic patients referred to bone scintigraphy as valuable information about renal function may be obtained by this procedure.