Title: Comparison of Colour Doppler Flow Imaging with Voiding Cystourethrography in the Detection of Vesicoureteric Reflux in Children
Authors: Dr Diya Rachel George, Dr Suny Thomas, Dr Mohanan K., Dr Paul V Puthussery, Dr Thahirabi K.A., Dr Mini M.V.
DOI: https://dx.doi.org/10.18535/jmscr/v5i5.162
Abstract
Introduction: Early detection and management of Vesicoureteric reflux (VUR) prevents the adverse renal effects. Voiding cystourethrography (VCUG) is considered the gold standard for diagnosis of VUR. Colour Doppler flow imaging (CDFI) is an attractive alternate imaging modality as it does not involve urethral catheterisation, contrast agent and ionising radiation.
Aim of the study: To assess the sensitivity, specificity, positive and negative predictive value of CDFI as compared to VCUG in the detection of VUR.
Materials and Methods: Seventy children between the ages of 1 to 12 years who were clinically suspected to have VUR were evaluated with VCUG and detection and grading of VUR was done. Then the sonologist who was unaware of the findings of VCUG performed CDFI. The sensitivity, specificity, positive and negative predictive values were calculated.
Results & Discussion: VUR was detected in 94 ureters in 56 patients by VCUG and in 78 ureters in 45 cases by CDFI. The sensitivity, specificity, positive and negative predictive values of CDFI were 77.7%, 91.3%, 94.8% and 66.7%. Accuracy was 82.1%. Sensitivity for low grade reflux was 27.78%, grade III reflux was 91.67%, grade IV and grade V reflux was 100%. There were 4 false positive results in CDFI. Identical grades were seen in 68 of the 74 ureters with reflux in both tests. There was significant coefficient of agreement (kappa) between grading by both tests (0.718).
Conclusion: The sensitivity of CDFI is low for low grade reflux which may be a physiological condition and excellent for grade IV and V reflux. The low negative predictive value means that a negative result on CDFI does not rule out VUR. There is good specificity and positive predictive value. The false positive rate of 2.9 % may indicate that CDFI may detect intermittent reflux missed on VCUG. Whenever CDFI detected reflux, there was good correlation between grades with a significant coefficient of agreement. The results indicate that CDFI may be used for follow up of children with VUR with VCUG being done only when CDFI is negative, hence reducing radiation exposure.
Keywords: Vesico-Ureteral Reflux; Ultrasonography, Colour Doppler; Urinary Tract Infections; Voiding Cystourethrography.
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