Detection of Muscle-Invasive Bladder Cancer on Biparametric MRI Using Vesical Imaging-Reporting and Data System and Apparent Diffusion Coefficient Values (VI-RADS/ADC)

Abstract

BACKGROUND: Vesical Imaging-Reporting And Data System (VI-RADS) was proposed to detect muscle-invasive bladder cancer (MIBC). OBJECTIVE: To evaluate the performance of VI-RADS and additional value of apparent diffusion coefficient (ADC) values measured on diffusion-weighted magnetic resonance imaging (MRI) for detecting MIBC. METHODS: A total of 176 patients undergoing MRI (multiparametric in 97 [55%] and biparametric in 79 [45%]) before transurethral resection of bladder tumor for primary bladder cancer were retrospectively identified. MRI findings were scored according to VI-RADS. The standardized tumor ADC (sT-ADC: tumor ADC/gluteus maximus ADC) was calculated and used to account for the incompatibility among different MRI protocols. The accuracy of VI-RADS, sT-ADC and their combination to detect MIBC was assessed using the AUC of the ROC curve. RESULTS: MIBC was pathologically confirmed in 46 patients (26%). AUC of VI-RADS to detect MIBC was 0.86. When cut-off of VI-RADS was set at≥3 and≥4, sensitivity/specificity were 78% /70% and 63% /96%, respectively. A lower sT-ADC (≤0.894) was significantly associated with muscle invasion (p < 0.01, AUC 0.79) with sensitivity 78% and specificity 79%. Combination of VI-RADS and sT-ADC improved the accuracy (AUC 0.94); sensitivity was 100% when VI-RADS≥3 or sT-ADC≤0.894 was considered positive, and specificity was 99% when VI-RADS≥4 and sT-ADC≤0.894 was considered positive. Incorporation of sT-ADC reduced under-staging of MIBC as VI-RADS < 3 by 100% and over-staging of non-MIBC as VI-RADS≥4 by 80%. CONCLUSIONS: Incorporation of ADC values into VI-RADS improves accuracy to detect MIBC in primary bladder cancer patients.

Systematic Review and Meta-Analysis of Vesical Imaging-Reporting and Data System (VI-RADS) Inter-Observer Reliability: An Added Value for Muscle Invasive Bladder Cancer Detection

“…Patient/tumors description, main findings, and study characteristics of the whole studies included are summarized in Table 1 . Of the 8 included articles [ 8 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ], 3 were conducted in Italy [ 8 , 19 , 24 ] and 2 in Japan [ 20 , 25 ], while the remaining were from China [ 21 ], Egypt, and Korea [ 22 , 23 ], covering an overall time period between February 2019 and April 2020. Overall, the number of patients included was 1016, varying from 32 to 340 in single experiences, while the prevalence of MIBC ranged from n = 6, 10.3% to n = 62, 50%.…”

“…Out of these, the article from Del Giudice et al [ 8 ] was the sole to analyze a large cohort of patients within prespecified limits of enrolling time (i.e., December 2017–May 2019) and more strict inclusion criteria with regard of previous BCa history and pathology related exclusion features (i.e., no CIS or non-urothelial carcinomas), while the other two experiences [ 22 , 24 ] did not report the same information thus suffering from potential higher RoB. The remaining five studies [ 19 , 20 , 21 , 23 , 25 ] were retrospective, assessing both urothelial and other histology variants of BCa. All studies were performed at single centers using either TURBT or a combination of TUR and partial or RC as the reference standard.…”

“…MpMRI had been performed prior to TURBT in all included studies except for one, which consisted of a mixture of pre- and post-TUR patients [ 21 ]. The majority of the studies implemented at a 3T MRI scanner [ 8 , 19 , 21 , 23 , 24 , 25 ] with T2-weighted images including slice thickness of 3 mm [ 8 , 19 , 22 , 24 , 25 ] or only 4 mm [ 20 , 21 , 23 , 25 ] respectively. Diffusion-weighted images were acquired homogeneously among the studies with high b values of 1000 s/mm 2 or higher.…”

“…Although protocols for DCE MRI varied among studies, temporal resolution was sufficient for the depiction of early enhancement of the inner layer followed by tumor enhancement required according to VI-RADS evaluation. Only the study of Sakamoto et al [ 25 ] compared two different MRI protocols within the same study population. Their findings were based on the multiparametric vs. biparametric approach with additional evaluation of apparent diffusion coefficient (ADC) measured on diffusion-weighted magnetic resonance imaging therefore will be subsequently separated from the rest of the cumulative meta-analysis estimates.…”

“…Overall, five studies [ 8 , 19 , 21 , 22 , 25 ] included two readers for the VI-RADS scoring process and for definitive consensus in the case of discrepancies assuming the most experienced opinion as the definitive one. In all these cases, a κ estimate with 95%CI or SE was reported.…”