Renal Dynamic Imaging in Diagnosis of Upper Urinary Tract Obstruction in Transplanted Kidney With ~(99)Tc~m-DTPA

Renal dynamic imaging with 99TcmDTPA is performed on 88 cases (110 times) transplanted kidney. Two kinds of renal scintigraphic are observed in recipients with supravesical obstruction of the graft. The first is, the regular type which is specifically characterized by activity defect area in kidney parenchyma during early uptake period followed by ureteropelvic retention.The second is,the tubular type which is featured by cortical retention and attenuation in collecting system during the whole test period with a special sign,"vacant kidney" Nonobstructive dilated calyces show similar signs as the regular type.Acute rejection reaction and tubule necrosis demonstrate obstructive time activity curves.However, the radioactivity retention appears in cortex. It is suggested that dilated calyces and obstructive renogram may be not feasible evidences for upper urinary tract obstruction. The signs of radioactivity attenuation in kindney parenchyma during early uptake period followed by ureteropelvic retention may be more valuable. For tubular obstruction,specified "vacant kidney" is the characteristic sign which may be very helpful for the diagnosis.