Vesical Imaging Reporting and Data System (VI-RADS) as an Imaging Biomarker of Urinary Bladder Tumour: A Cross-sectional Study

Introduction: The Vesical Imaging Reporting and Data System (VI-RADS) score is an emerging imaging tool that can predict detrusor invasion of bladder tumours. The VI-RADS score has been introduced for standardised reporting of Multiparametric Magnetic Resonance Imaging (MP-MRI) in bladder tumours. It incorporates components of structural (T2-weighted), functional (DWI), and Dynamic Contrast-Enhanced imaging (DCE). Aim: To assess the role of Multiparametric MRI- (MP-MRI) based VI-RADS score in predicting detrusor invasion in bladder tumour patients determined by Histopathological Examination (HPE). Materials and Methods: The present cross-sectional study was conducted in the Department of Radiodiagnosis and the Department of Urology at IPGME&R, Kolkata, India, from January 2021 to August 2022. Adult patients with cystoscopically proven bladder tumours were included in the study after providing informed consent. Each patient was assessed by cystoscopy and MP-MRI of pelvis. Subsequently, each patient underwent Transurethral Resection of Bladder Tumour (TURBT) and biopsy for HPE.Both descriptive and analytical statistics were used in the present study. The diagnostic accuracy of the VIRADS score with HPE have been analysed. The association between VI-RADS scores and ADC values, tumour grades, and morphological variants were also assessed. Efficacy of individual components of VI-RADS score with muscle invasiveness is also analysed by Cohen’s kappa values. Results: The median age of the study subjects is 60 years, with 29 out of 35 subjects being male (82.8%). Known risk factor smoking is detected in 11 subjects (31.4%). The present study showed sensitivity of 100% and specificity of 76.1% with a cut-off VI-RADS score of 3; AUC 0.869 (CI- 0.712 to 0.959), p<0.0001. VI-RADS score is predictor of muscle invasion and tumour grades (Odds ratio 5.43, CI 1.77 - 16.61, p<0.01). ADC values are more related to tumour grades (lower median value 0.00090 vs 0.00097; p<0.05). Individual components of the VIRADS score (T2WI, DCE, DWI) are effective in predicting tumour muscle invasion (AUC values, respectively, 0.886, 0.869, 0.869; p<0.0001). Sessile variants of tumours have a higher VI-RADS score compared to other morphological types (median 4 vs 2, with p<0.05). Conclusion: The results of the present study suggest that MPMRI-based VI-RADS score is an imaging predictor of bladder tumour detrusor invasion. and also a predictor of tumour grades.