99Tcm-DMSA as a dynamic imaging agent for estimating renal blood flow. A comparison with 99Tcm-DTPA.

A technique for estimating fractional renal blood flow (RBF) from the early part of the 99Tcm-diethylenetriaminepentaacetate (DTPA) renogram has been described previously and its reproducibility validated in the pig model. The technique is assumed to be applicable to any recirculating gamma-emitting tracer compound. The aim of this study was to determine whether the same method could be applied to 99Tcm-dimercaptosuccinic acid (DMSA) which has been largely neglected as a dynamic imaging agent. Paired estimates of fractional RBF were obtained in Large White (n = 16) and Göttingen miniature pigs (n = 6) in three groups: group 1, paired 99Tcm-DTPA studies; group 2, paired 99Tcm-DMSA studies; group 3, alternate 99Tcm-DTPA and 99Tcm-DMSA studies. The results showed good agreement between paired results independent of whether 99Tcm-DTPA or 99Tcm-DMSA was used, supporting the assumption that the technique is applicable to any recirculating gamma-emitting tracer compound. The demonstration that fractional RBF can be reliably estimated from the DMSA renogram means that, if required, it may be combined in a single nuclear medicine procedure with conventional static DMSA renal imaging.