Tc-99m DTPA renal scintigraphy using deconvolution analysis with six functional images of the mean time to evaluate acute pyelonephritis

In 38 children with proved P-fimbriated Escherichia coli acute pyelonephrit is, Tc-99m DTPA dynamic renal scintigraphy in the zoom mode using deconvolu tion analysis was performed, and the results were compared with those of Tc -99m DMSA scans. From the dynamic study, six functional images of the mean time were generated. Each functional image was analyzed separately to searc h for focal areas of increased mean time within the kidney contour, especia lly over the kidney parenchyma, Time-activity curves from these areas were generated and analyzed. Tc-99m DMSA scintigraphy showed generalized or foca l decreased uptake in 32 (41.8%) kidneys, and deconvolution analysis of Tc- 99m DTPA scintigraphy revealed pathologic renographic curves in 58 (77.6%) kidneys. Prolonged whole-kidney and normal renal parenchymal transit times (dilatation without obstruction) were found in 38 (50%) kidneys, whereas pr olonged whole-kidney and renal parenchymal transit times (dilatation with o bstruction) were observed in 20 (27.6%) kidneys. Separate analysis of each of the six functional images of the mean time showed focal areas of increas ed mean time in the kidney parenchyma of 11 kidneys. In five cases, time-ac tivity curves from these areas showed a sharp increase of activity on the d escending part of the curve, which might reflect the return of urine from t he collecting system into kidney cortex (i.e., intrarenal reflux), These re sults showed that in a urinary tract with acute pyelonephritis, urodynamic changes may lead to obstructive nephropathy and intrarenal reflux, Tc-99m D TPA renal scintigraphy in the zoom mode using deconvolution analysis with s ix functional images of the mean time has proved to be a valuable method to evaluate acute pyelonephritis, thus allowing dynamic and morphologic analy sis of the urinary tract at the same time.