Neither renal-bladder ultrasound nor dimercaptosuccinic acid scans are sufficiently accurate to detect vesicoureteral reflux (VUR), investigators concluded based on a systematic review.
Nader Shaikh, MD, and colleagues at Children’s Hospital at Pittsburgh, analyzed data from 42 cross-sectional or cohort studies comparing results of the index tests—renal-bladder ultrasound (RBUS) or dimercaptosuccinic acid (DMSA) scans—with the results of radiographic voiding cystourethrography (VCUG) findings in children younger than 19 years with a culture-confirmed urinary tract infection (UTI).
Of the 42 studies, 20 reported data on the test performance of RBUS in detecting VUR. The summary sensitivity and specificity estimates for RBUS scans were 44% and 78%, respectively, the authors reported online in the Cochrane Database of Systematic Reviews. The 11 studies that reported data on the test performance of RBUS in detecting high-grade VUR found that the summary sensitivity and specificity estimates were 59% and 79%, respectively. The 19 studies that looked at the test performance of DMSA in detecting VUR showed that the summary sensitivity and specificity estimates were 75% and 48%, respectively. Ten studies reported data on the accuracy of DMSA in detecting high-grade VUR. The summary sensitivity and specificity estimates were 93% and 44%, respectively.
The investigators noted that a child with a negative DMSA test has a less than 1% probability of having high-grade VUR, performing a screening DMSA scan will result in a large number of children falsely labeled as being at risk for high-grade VUR. “Accordingly, the usefulness of the DMSA [scan] as a screening test for high-grade VUR should be questioned,” they concluded.
Dr Shaikh’s group noted that there is considerable interest in detecting VUR because its presence has been linked to an increased risk of UTI and renal scarring, especially when VUR is severe. VCUG is the gold standard for diagnosing VUR and grading its severity. VCUG, however, requires bladder catheterization and exposes children to radiation, “so there has been growing interest in other screening methods that could identify at risk children without the risks and discomfort associated with VCUG.”