CT and 99mTc-DMSA scintigraphy in adult acute pyelonephritis: a comparative study

The aim of this prospective study was to evaluate the relative value of CT and (99m)Tc-DMSA scintigraphy in the diagnosis of acute pyelonephritis (APN) in adult patients suspected of having urinary tract infection.

The study was conducted in 36 patients presenting with symptoms suggestive of urinary tract infection. Plain B-mode sonography, CT with contrast medium, and (99m)Tc-DMSA scintigraphy of the kidneys were performed in all patients. Both CT and (99m)Tc-DMSA scintigraphy were performed within 72 h after admission.

Twelve patients with clinical and biological signs of urinary tract infection had no CT or (99m)Tc-DMSA scintigraphy abnormalities. Among these patients, lower urinary tract infection was found in 10 patients and 2 patients had ureteral obstruction. In the 24 remaining patients, the diagnosis of APN was made. Among these patients, a correlation was found between CT and (99m)Tc-DMSA scintigraphy in 11 cases. In two cases, both examinations were normal, and in nine cases, both were abnormal. In 11 cases of the 13 remaining patients, abnormal CT was found with normal (99m)Tc-DMSA scintigraphy, whereas the 2 last cases had normal CT and abnormal (99m)Tc-DMSA scintigraphy results. In two cases, bilateral lesions found on CT manifested as unilateral abnormalities on (99m)Tc-DMSA scintigraphy images.

The diagnosis of APN in adult patients is based on clinical presentation and biological findings. Few studies have compared (99m)Tc-DMSA scintigraphy with CT in the detection of parenchymal involvement in APN. We conclude that CT is more accurate than (99m)Tc-DMSA scintigraphy in the detection of APN lesions in adult patients.