Quantitative Assessment of Renal Function In Children with UPJO By Contrast-enhanced Ultrasound: A Pilot Study

Abstract

Background: Contrast-enhanced ultrasonography (CEUS) is a new potential modality for the quantitative evaluation of the microvascular perfusion of a parenchymal organ.Objective: To prospectively evaluate the diagnostic value of CEUS in assessing renal function in patients with ureteropelvic junction obstruction (UPJO).Methods: The study protocol was approved by the local ethics committee, and written informed consent was obtained from the patients’ parents or guardians.Ultrasonography (US), CEUS, and radioisotope renography were performed in 51 children (42 boys, 9 girls; mean age, 6.75 ± 4.14 years) with unilateral UPJO. The slope of the ascending curve (A), time to peak (TTP), peak intensity (PI), and area under the curve (AUC) were recorded during CEUS; the quantitative data were calculated by the QLAB system (semiautomated border tracking, Philips Healthcare) software. Sensitivity and specificity values were determined for CEUS and compared with radioisotope renography.Results: CEUS depicted 102 kidneys in 51 patients, in whom the perfusion time-intensity curve（TIC）was determined. The TIC of renal cortical perfusion in all groups showed an asymmetrical single-peak curve, which could be clearly distinguished between the experimental group and the control group. Compared to the control group, the TTP was markedly prolonged but A was significantly decreased in the experimental group (P < 0.05). The ROC curve drawn to differentiate the differential renal function (DRF) using the TTP value provided an area under the ROC curve (AUROC) of 0.86. The diagnostic performance of contrast-enhanced US was better than that of US, as the sensitivity and specificity values were 92.86% and 76.14%, respectively.Conclusions: This preliminary experience represents the first report of evaluating the diagnostic value of CEUS in assessing renal function in children with UPJO. CEUS is a highly sensitive, rapid, and cost-effective diagnostic imaging modality for detecting and monitoring renal function noninvasively.