Correlation of ureteric jet angle (UJA) with vesicoureteral reflux grade and its assessment as a noninvasive diagnostic parameter to detect vesicoureteral reflux
Authors: Maravi Poornima , Kaushal Lovely , Rathore Bhagyashree , Trivedi Anshuli 
Published: June 2023

Abstract
Background
Vesicoureteral reflux (VUR) is an essential urogenital entity affecting infants and younger children. Many patients present late with recurrent urinary tract infections (UTIs), which lead to chronic pyelonephritis, renal scarring, and end-stage renal disease (ESRD). This progression in disease adds to significant morbidity and mortality in the paediatric age group. Voiding cystourethrography (VCUG) is the investigation of choice which is an invasive procedure and is related to the risk of ionizing radiation and iodinated contrast administration. Ureteric jet angle (UJA) is a Doppler parameter that can be obtained by measuring the angle between the horizontal axis of the floor of the optimally distended bladder and the Doppler ureteric jet at the ureteral opening into the bladder. The study aimed (1) to investigate the correlation of UJA with VUR grade and (2) to assess the utility of UJA as a noninvasive diagnostic indicator to diagnose VUR as an alternative to VCUG.

Method
All paediatric patients with urinary complaints were evaluated by voiding cystourethrography (VCUG) for assessment of grades of VUR, followed by colour Doppler evaluation of ureteric jets. VCUG interpretations were made.UJA was calculated as the angle between the long axis of the colour Doppler jet and the horizontal axis of the floor of the optimally distended urinary bladder on colour Doppler examination. Ureteric jet angles were recorded on both sides irrespective of the presence of VUR, and data were analysed using SPSS. The correlation coefficient (r) with p value was calculated. The diagnostic efficacy of UJA (58° or more) to detect VUR was assessed by calculating sensitivity, specificity, PPV, NPV, positive LR and negative LR. The AUC was calculated to evaluate the diagnostic efficacy of UJA 58° or more to detect VUR.

Results
In total, 34 (68 renal units) children (8 months–12 years), including 20 males (M) and 14 females (F), examined. The mean age was 4.96 ± 2.87 years for the total population, including 4.60 ± 2.02 years for boys and 5.47 ± 2.75 years for girls. Twenty-one patients (10 girls and 11 boys) showed VUR on MCUG. Eight patients showed high grades (grade III–V), including seven boys and a girl. The range of UJA in VUR-negative patients was 27–60° with a median angle of 42.03°. VUR-positive patients showed an angle range of 32–71°with a median angle of 62.13°. High-grade VUR was seen in 8 patients with an angle range of 59–84° and a median angle of 76.31°. A positive correlation (r = 0.81) was noted between UJA and VUR grading. The sensitivity and specificity of angle > 58° to detect VUR were 0.66 and 0.92 with PPV 0.93 and NPV 0.63. Yuden’s J value was 58°. The value for the area under the curve was 0.7.

Conclusions
Positive linear correlation was seen between UJA and VUR grades with high specificity and positive predictive value. The Diagnostic Utility of UJA 58° as a screening method to detect severe VUR was acceptable and can be further studied with a larger sample size.