Development and validation of a bladder trabeculation grading system in pediatric neurogenic bladder

Bladder trabeculation (BT) is commonly noted on cystogram images of patients with neurogenic bladder (NB). BT is associated with a hostile bladder often requiring prompt, more aggressive management. We aimed to define and validate a reliable grading system for BT severity. The proposed grading system will improve clinicians and radiologist's communication and serve as a foundation for future studies in the field of NB. The study was conducted in two phases: 1) Development of a grading system for BT and 2) testing of the proposed grading system for reliability and validity. Agreement between raters was assessed using Cohen's Kappa. Inter-rater reliability and intra-rater reliability was assessed using intra-class correlation coefficients (ICC) and Spearman's p (rho) correlation coefficient. The content of the grading system was assessed for face validity by senior pediatric urology and radiology experts. We observed inter-rater reliability with ICC of 0.998 (95%CI 0.996-0.999, p < 0.001), and a Cohen's Kappa ranging from 0.795 to 1.0, p < 0.001 and Spearman's p (rho) correlation coefficient ranging from 0.910 to 1.0, p < 0.001 between raters on the decided grades of BT. In conclusion, we established a defined grading system for BT severity that has substantial inter/intra-rater reliability and validity. This grading system could be useful for improving clinician and radiologist's communication about the status of a child's bladder wall and serve as a foundation for future studies assessing severity of NB.