Diagnostic value of signal intensity of MR imaging for renal congestion in nutcracker syndrome: report of 39 children

Abstract

Objective To investigate the findings of MR imaging and their clinical value in diagnosis of left renal congestion in children with nutcracker syndrome (NCS). Methods All the 39 children (23 boys and 16 girls, mean age of 11±3 years) with NCS diagnosed at our hospital from Jun 2018 to Mar 2019 were enrolled in this study. Plain scanning sequence of T2WI was performed to measure the difference in signal intensity between the renal medulla and cortex (MC value) and calculate the absolute value of the difference between the MC values of both kidneys (BR value). Then, the children were divided into congestion group (n=25) and non-congestion group (n=14) according to whether a different renal signal existed between the 2 kidneys. The correlation of MRI findings and clinical biochemical data were analyzed with aid of statistics software SPSS 21.0. Results In the patients with congested left kidney, the medullary signals were reduced at T2WI, which rendered a distinct signal difference between the 2 kidneys. The patients from the congestion group had significantly higher BR value (P 2.4, left renal congestion was valid, with higher diagnostic value (AUC=0.894), but 24-hour urine protein quantification (AUC=0.579) and serum levels of urea nitrogen (AUC=0.579) and urinary creatinine (AUC=0.527) had lower diagnostic values. Conclusion Inter-kidney MRI signal difference in children with NCS is a reliable sign to judge whether a congested left kidney exists; whereas clinical biochemical indices are not.

Keywords

• nutcracker syndrome
• renal congestion
• magnetic resonance imaging
• children