Comparison of magnetic resonance urography to dimercaptosuccinic acid scan for the identification of renal parenchyma defects in children with vesicoureteral reflux

OBJECTIVE

The objective of this study was to compare the accuracy of dimercaptosuccinic acid (DMSA) renal scan to magnetic resonance urography (MRU) in the identification of renal parenchyma defects (RPD).

MATERIALS AND METHODS

Twenty-five children with history of acute pyelonephritis and vesicoureteral reflux underwent DMSA scan and MRU to determine the presence of RPD. DMSA scans and MRUs were each evaluated by two radiologists and agreement achieved by consensus. Discordant DMSA-MRU findings were re-evaluated in a side-by-side comparison and an ultimate consensus reached.

RESULTS

The ultimate consensus diagnosis was 18 kidneys with RPDs in 15 patients, of which five were classified as mild RPDs, six as moderate RPDs, and seven as severe RPDs. Although DMSA scan and MRU were similar in their ability to diagnose RPDs, MRU was considered to represent the true diagnosis in 11 of the 12 discordant cases in consensus review by four pediatric radiologists. MRU showed a much higher inter-observer agreement with a weighted kappa of 0.96 for both kidneys compared to 0.71 for the right kidney and 0.86 for the left kidney by DMSA scan.

CONCLUSIONS

Our results suggest that MRU is superior to DMSA scan in the identification of renal parenchyma defects.

Sonography of the neonatal genitourinary tract

Ultrasound has become the modality of choice for the evaluation of the neonatal genitourinary tract. High frequency linear, vector, and curved array transducers (7 MHz, 5 MHz, 12 MHz) and portability of the equipment make a rapid bedside evaluation with exquisite anatomic detail possible. A major advantage of sonography over other modalities is real time observation and circumvention of sedation.