Diagnosing Acute Pyelonephritis with CT, 99mTc-DMSA SPECT, and Doppler Ultrasound: A Comparative Study

PURPOSE With growing interest in early imaging, the aim of our study was to define the most practical modality for routine clinical use for the diagnosis of acute pyelonephritis (APN). We compared the sensitivity of enhanced computerized tomography (CT), dimercaptosuccinic acid (DMSA) scintigraphy, and Doppler ultrasonography (DUS) by using clinical findings as the standard of reference. MATERIALS AND METHODS A total of 207 APN patients (191 women, 16 men; mean age, 49.4 years; range, 17-88 years) were enrolled in this study. All the patients underwent imaging modalities during hospitalization. SPECT images were obtained 4 hours after injection of (99m)Tc-DMSA. Transverse and coronary CT images were obtained before and after injection of the contrast agent. DUS was performed in the longitudinal, transverse, and coronal planes. All the images were read independently by a single radiologist and a nuclear medicine specialist. The sensitivity of each modality for detecting APN was compared. RESULTS CT showed significantly superior sensitivity compared with that of DUS (81.0% vs. 33.3%, respectively, n=147). DMSA scintigraphy also showed significantly superior sensitivity compared with that of DUS (74.7% vs. 33.3%, respectively, n=150). Compared with DMSA scintigraphy, CT showed superior sensitivity, but the difference was not statistically significant (81.0% vs. 74.8%, respectively, n=147, p=0.163). CONCLUSIONS For cases of clinically suspected APN, CT and DMSA scintigraphy appear to be equally sensitive and reliable for detecting APN, although CT is more practical in various fields. DUS was significantly less sensitive.