Radionuclide studies of chronic schistosomal uropathy

Fifty patients with chronic urinary tract schistosomiasis were studied with 99mTc-DTPA. All had a flow study, sequential analog imaging, and digital imaging for 25-35 minutes (20-sec. frames). Time-activity curves (DTPA renograms) were extracted; 12 patients had 131I-Hippuran probe renograms as well. Renal changes included diminished perfusion and structural abnormalities ranging from minor calyceal dilatation to overt hydronephrosis. Ureteral changes included dilatation, tortuosity, and kinking. Marked distortion of the ureterovesical junction was seen in some patients due to periureteral and perivesicular fibrosis, which is a major factor in upper urinary tract damage. Renograms showed varying obstruction and parenchymal damage. Nuclear medicine complements excretory urography and is sometimes preferable for visualization of the ureters. After the initial urogram, sequential DTPA scanning and renography are sufficient for follow-up.