LAUSR

BACKGROUND To evaluate sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) of renal ultrasonography (US) in predicting renal uptake defects or reduced renal function at Tc-99m dimercaptosuccinic acid (DMSA) scan (primary outcome). We also evaluated which factors could be associated with Tc-99m DMSA renal scan anomalies METHODS: We retrospectively included all the patients with vesico-ureteral reflux (VUR) undergoing the first Tc-99m DMSA renal scan within 3 months from the most recent renal US between 2016 and 2018. RESULTS Sensitivity, specificity, PPV, and NPV of US in predicting abnormal Tc-99m DMSA scan were 38.9%, 91.5%, 71.9%, and 72.9%, respectively. Different length between the kidneys, expressed as standard deviation score (SDS), showed an area under the receiver operating characteristic curve of 0.70 (95% CI, 0.60-0.80; p < 0.0001) when evaluated as predictor of abnormal Tc-99m DMSA scan. A different length between the two kidneys >1.11 SDS had 91.5% sensitivity and 57.6% specificity. At multivariate analysis, the factors with significantly increased odds ratio of abnormal Tc-99m DMSA scan were difference in length between two kidneys >1.11 SDS and dilated VUR. CONCLUSIONS The Tc-99m DMSA scan remains the gold standard to detect renal parenchymal anomalies. A different length between the kidneys >1.11 SDS and dilated VUR are predictors of abnormal Tc-99m DMSA renal scan.