Utility of ultrasonography in the evaluation of renal scarring using dimercaptosuccinic acid scan as the gold standard

ABSTRACT

Dimercaptosuccinic acid [DMSA] is considered the most sensitive tool for diagnosis of renal scars. This study was done to evaluate the utility of renal ultrasound scanning in detection of renal scars in children with urinary tract infection [UTI] compared to DMSA scan as the gold standard. During 4 years period, we evaluated 202 children with UTI for detection of renal scars using ultrasound and DMSA renal scanning. All patients underwent renal ultrasound and DMSA scan for detection of renal scars. Renal scars were classified into diffuse or focal types. The data were statistically analyzed to evaluate the sensitivity and specificity of renal ultrasound in detection of renal scars. Two hundred and two patients [404 renal units] scanned with ultrasound and DMSA for detection of renal scars. Male to female ratios were 11.8 [71 males and 131 females]. DMSA proved the presence of scars in 145 units [35.89%], Ultrasound was able to detect scars in 52 units out of 145 with sensitivity; specificity, PPV, and NPV ultrasound in detection of scars were 35.68%, 91.12%, 69.33%and 71.73%, respectively. DMSA scan detect focal scars in 85 units while diffuse one in 60 units. Ultrasound was able to detect focal scars in 20 out of 85 units [23.5%] with sensitivity, specificity, PPV, and NPV were 23.5%, 94.3%, 52.6% and 82.2% respectively. While diffuse scars in 32 units out of 60 [53.3%] with sensitivity, specificity, PPV, and NPV were53.3%, 98.5%, 86.5%and 92.5%, respectively. Although ultrasonography has a good specificity for detection of renal scarring compared with DMSA scan. Ultrasonography cannot replace DMSA scan in the evaluation of focal renal scarring. However ultrasound might be used for selection of the cases that should be underwent DMSA renal scan