Role of Late DMSA Renal Scan in Detecting High-Grade Vesicoureteral Reflux

Area of Science:

• Pediatric Nephrology
• Diagnostic Imaging
• Urology

Background:

• Febrile urinary tract infections (fUTI) in children can indicate underlying vesicoureteral reflux (VUR).
• Timely diagnosis of high-grade VUR is crucial to prevent renal scarring and complications.
• Late dimercaptosuccinic acid (DMSA) renal scans are utilized for evaluating renal scarring and VUR.

Purpose of the Study:

• To assess the diagnostic performance of late DMSA scans in identifying high-grade VUR (grades III-V) in children over 3 years old with a history of fUTI.
• To determine if a normal late DMSA scan can reliably exclude high-grade VUR, thereby avoiding the need for voiding cystourethrogram (VCUG).

Main Methods:

• Retrospective diagnostic accuracy study analyzing clinical records of 122 children (3-18 years) with fUTI history.
• Exclusion of patients with pre-existing renal abnormalities or prior genitourinary imaging.
• Comparison of late DMSA scan findings with voiding cystourethrogram (VCUG) as the gold standard for VUR grading.

Main Results:

• Abnormal DMSA scans were significantly associated with all grades of VUR (p<0.00001) and specifically with high-grade VUR (p<0.00001).
• For high-grade VUR, late DMSA scans demonstrated 100% sensitivity and 100% negative predictive value (NPV).
• Overall VUR detection by DMSA had 93.1% sensitivity, 75% specificity, 92.3% NPV, and 77.1% positive predictive value (PPV).

Conclusions:

• A normal late DMSA scan in older children reliably predicts the absence of high-grade VUR.
• This finding suggests that a normal late DMSA scan can obviate the need for VCUG in this patient group.
• Late DMSA scan can serve as a valuable screening tool for children with fUTI who were not investigated promptly during the acute infection phase.