Vesical Imaging-Reporting and Data System (VI-RADS): Inter-Observer Agreement and Impact of Reader's Experience

Background The Vesical Imaging Reporting and Data System (VI-RADS) is based on multiparametric MRI (mpMRI), to provide accurate information to differentiate between muscleinvasive bladder cancer (MIBC) and non-muscle –invasive bladder cancer (NMIBC). Aim of the Work To evaluate inter-observer agreement according to observer experience and diagnostic performance of the new scoring system based on magnetic resonance imaging called Vesical Imaging-Reporting and Data System (VI-RADS) to differentiate between invasive and non-invasive bladder cancer. Patients and Methods This study included 38 patients who were diagnosed with Transitional Cell Carcinoma (TCC) who underwent multiparametric Magnetic Resonance Imaging (mpMRI) at the department of Radiodiagnosis in Ain-Shams University from April 2021 till October 2021. Three radiologists with different levels of experience reviewed and scored all MRI examinations according to VI-RADS, compared them with the histopathological findings and inter-observer agreement was assessed. Results This study included 38 patients; the patients’ age ranged from 47 to 83 years old with mean age 62.26 (+8.18 SD). The total number of lesions in all cases were 43; 12 of them (27.9 %) were non-muscle-invasive urothelial carcinoma and 31 (72.1%) were muscle invasive. Using a VI-RADS score of 4 or greater as the cutoff value, the sensitivity, specificity, accuracy, PPV, and NPV for reader 1 were 96.8%, 83.3 %, 93%, 93.8%, and 90.9%, and for reader 2 were 93.5 %, 91.7%, 93%, 96.7% and 84.6%, and finally for reader 3 were 96.8%, 83.3%, 93 %, 93.8% and 90.9%. The agreement was excellent between each reader with the pathology and the readers with each other (Kappa over 0.75). Conclusion The Vesical Imaging-Reporting and Data System (VI-RADS) is an effective comprehensive scoring system, with satisfactory sensitivity, specificity, and diagnostic value for detecting detrusor muscle invasion. We can recommend VI-RADS scoring for use in the prediction of detrusor muscle invasion in patients with bladder cancer, but further multicenter validation studies containing multiple magnetic field strength devices also must be conducted.