Objective: To evaluate the effectiveness of fluoroscopic capture spot (FCS) image in diagnosing vesicoureteral reflux (VUR) and other urinary tract pathologies during VCUG in the pediatric population.

Material and Method: The study was done prospectively in 248 VCUG examinations. Each test consisted of FCS images and the corresponding digital radiographic spot (DRS) images taken nearly simultaneously. Each set of data was reviewed by three pediatric radiologists for the diagnosis of VUR, urinary tract pathologies, presence of a fistula, and other abnormalities. By using DRS images as a gold standard, the effectiveness of FCS images was evaluated. The present study protocol was approved by the Ethics Committee of Faculty of Medicine Siriraj Hospital, Mahidol University (Si073/2012).

Results: There was no significant difference between FCS and DRS images in defining grade of VUR (p = 0.194). FCS and DRS diagnostics were in perfect agreements when diagnosing the presence or absence of VUR, urinary tract pathologies (kidney, ureter, bladder, urethra), presence or absence of fistula, and other abnormalities. When images classified as non-significant VUR (no VUR, grade 1 VUR) or significant VUR (VUR grade 2-5), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for diagnosing the non-significant VUR were 99.1%, 100%, 96.7%, 98.9%, and 100%, respectively. When images classified as negative/ low-grade VUR (grade 1-2) or moderate/high grade VUR (VUR grade 3-5), accuracy, sensitivity, specificity, PPV, and NPV for diagnosing negative/low-grade VUR were 99.7%, 100%, 98.8%, 99.8%, and 100%, respectively. There were excellent correlations among three readers.

Conclusion: Image from fluoroscopic capture spot technology is sufficient to diagnose VUR and non-VUR urinary tract abnormality on VCUG examination.

Keywords: Voiding cystourethrography, Vesicoureteral reflux, Radiation dose reduction, Children, Urinary tract abnormality