Diagnostic Value of DCE-MRI and Tofts Model in Children with Unilateral Hydronephrosis

Background: Hydronephrosis is a common condition, and the correct diagnosis of hydronephrosis is necessary to improve the early diagnosis rates of pediatric hydronephrosis. Objective: The objective of this study is to explore and analyze the diagnostic value of dynamic contrast- enhanced magnetic resonance imaging (DCE-MRI) analyzed using the Tofts model in children with unilateral hydronephrosis. Methods: We retrospectively selected data from 88 children with unilateral hydronephrosis treated in our hospital from September 2018 to October 2020. Routine and DCE-MR renal image indexes were collected and their pharmacokinetic variables were calculated based on the Tofts model to compare kinetic parameters of affected and normal kidney. We compared the renal parenchymal thickness and other renal function indexes in children with different degrees of hydronephrosis, and drew receiver operating characteristic (ROC) curves to evaluate the diagnostic value of this approach in children with hydronephrosis. Results: The Ktrans, Kep, and Ve values in the diseased kidneys were lower than those in the normal ones (P<0.05). The thickness of the healthy renal parenchyma in children with severe hydronephrosis was higher than in children with moderate and mild hydronephrosis, but the renal parenchyma thickness and the thickness ratio of renal parenchyma on the affected side were lower than those in children with moderate and mild hydronephrosis (P<0.05). Sensitivity, specificity and accuracy of DCE-MRI and Tofts model in the diagnosis of hydronephrosis in children were higher than those of a single DCE-MRI (P<0.05). The area under the ROC curve for the DCE-MRI and Tofts model approach for the diagnosis of hydronephrosis in children was 0.789 (95% CI, 0.72-0.859), and the sensitivity and specificity were 86.36% and 71.59%, respectively. Conclusions: DCE-MRI and Tofts model can provide a clear picture of renal morphology, and renal function evaluation parameters. They have high sensitivity and specificity in the diagnosis of hydronephrosis in children.