TC-99M DMSA SPECT IMAGING IN PATIENTS WITH ACUTE SYMPTOMS OR HISTORY OF UTI - COMPARISON WITH ULTRASONOGRAPHY

Although planar cortical scintigraphy has been demonstrated to be a se nsitive test for the detection of renal infection and scarring, one cr iticism has been radiation dose to the renal cortex. Recent studies of cortical SPECT suggest a sensitivity for detection of lesions equal t o, or greater than, that of planar scans. The authors prospectively pe rformed SPECT scans on 36 patients referred for recurrent urinary trac t infection (UTI) (11 of 36), or recent onset of symptoms of UTI (25/3 6) after 30-40% of the standard 130 MBq (3.5 mCi) adult dose of Tc-99m DMSA was administered. Comparison was made with ultrasonography (US) performed at, or near, the same time. Of 67 kidneys evaluated, 34 (51% ) demonstrated focal cortical loss on Tc-99m DMSA scintigraphy, 1 kidn ey was small in size, and 32 kidneys were normal. Abnormalities were n oticed in only 13 (19%) of kidneys on US. Previously, US has been the primary imaging modality in the evaluation of the young patient with U TI. Triple-headed Tc-99m DMSA SPECT scintigraphy is a more sensitive, low-dose (12 mGy, 1.2 r) method of detecting renal cortical abnormalit ies. As such, it is a more appropriate test for identifying sites of c ortical infection and scarring and for following patients on prophylac tic therapy for evidence of asymptomatic breakthrough infections.