A Potential Application of Dynamic Contrast-Enhanced Magnetic Resonance Imaging Combined with Photodynamic Diagnosis for the Detection of Bladder Carcinoma in Situ: Toward the Future ‘MRI-PDD Fusion TURBT’

The detection of carcinoma in situ (CIS) is essential for the management of high-risk non-muscle invasive bladder cancers. Here, we focused on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) combined with photodynamic diagnosis (PDD) for the detection of CIS. A total of 45 patients undergoing pre-surgical DCE-MRI and PDD-assisted endoscopic surgery accompanied by biopsies of the eight segmentations were analyzed. Immunohistochemical analysis of the biopsies revealed hypervascularity of CIS lesions, a cause of strong submucosal contrast-enhancement. It was found that 56 (16.2%) of 344 biopsies had pathologically proven CIS. In the DCE-MRI, the overall sensitivity and specificity for detecting CIS were 48.2% and 81.9%, respectively. We set out two different combinations of PDD and DCE-MRI for detecting CIS. Combination 1 was positive when either the PDD or DCE-MRI were test-positive. Combination 2 was positive only when both PDD and DCE-MRI were test-positive. The overall sensitivity of combinations 1 and 2 were 75.0% and 37.5%, respectively (McNemar test, vs PDD alone; p = 0.041 and p < 0.001, respectively). However, the specificity was 74.0% and 91.7%, respectively (vs PDD alone; both p < 0.001). Our future goal is to establish ‘MRI-PDD fusion transurethral resction of the bladder tumor (TURBT), which could be an effective therapeutic and diagnostic approach in the clinical management of high-risk disease.