Combining Multiparametric MRI Radiomics Signature with the Vesical Imaging-Reporting and Data System (VI-RADS) Score to Preoperatively Differentiate Muscle Invasion of Bladder Cancer

Background: The treatment and prognosis for muscle-invasive bladder cancer (MIBC) and non-muscle-invasive bladder cancer (NMIBC) are different. We aimed to construct a nomogram based on the multiparametric MRI (mpMRI) radiomics signature and the Vesical Imaging-Reporting and Data System (VI-RADS) score for the preoperative differentiation of MIBC from NMIBC. Methods: The retrospective study involved 185 pathologically confirmed bladder cancer (BCa) patients who received mpMRI before surgery between August 2014 to April 2020. A total of 2,436 radiomics features were quantitatively extracted from the largest lesion located on the axial T2WI and from dynamic contrast-enhancement images. After feature selection, radiomics signatures were developed in the training set (n=129) and validated in the validation set (n=56) . Univariable and multivariable logistic regression were used to develop a nomogram. Findings: The radiomics signature generated by the least absolute shrinkage and selection operator classifier had the best capacity for muscle-invasive status differentiation in both the training (accuracy: 90.7%, area under the curve (AUC): 0.934) and validation sets (accuracy: 87.5%, AUC: 0.906). Incorporating the radiomics signature and VI-RADS score, the nomogram demonstrated better discrimination and calibration both in the training set (accuracy: 93.0%, AUC: 0.970) and validation set (accuracy: 89.3%, AUC: 0.943). Decision curve analysis showed the clinical usefulness of the nomogram. Interpretation: The mpMRI radiomics signature may be useful for the preoperative differentiation of muscle-invasive status in BCa . The proposed nomogram integrating the radiomics signature with the VI-RADS score may further increase the differentiation power and improve clinical decision making. Funding Statement: Shanghai Science Committee Foundation and Shanghai Youth Science and Technology Talents Sailing Program. Declaration of Interests: This study was funded by the Shanghai Science Committee Foundation (grant number 19411967700) and Shanghai Youth Science and Technology Talents Sailing Program (20YF1437200). Ethics Approval Statement: This study was approved by the institutional review board, and informed consent of patients was waived due to its retrospective nature.