Comparison between conventional and diffusion-weighted magnetic resonance imaging in predicting grade and stage of urinary bladder cancer

Abstract

Background Urinary bladder cancer is the second most common neoplasm of the urinary tract. Tumor staging and regional disease spread are the strongest predictors of treatment outcome. Our study aims to compare the diagnostic performance of conventional and diffusion-weighted magnetic resonance imaging (DW-MRI), using a 3T MR scanner, in grading and staging of urinary bladder cancer with histopathologic correlation. Results The sensitivity, specificity, and accuracy of combined use of HR T2WI and DWI were better than using HR T2WI only to differentiate T1 stage from further stages (95%, 100%, and 98%, respectively). Differentiating organ confined bladder cancer (T1 and T2 stages) from tumors with extravesical extension was better when using both HR T2WI and DWI than using HR T2WI (accuracy 100% and 93%, respectively). Kappa agreement was better when using both HR T2WI and DWI than HR T2WI only (0.963 and 0.496 respectively). Grade III lesions showed statistically significant lower ADC values than grades I and II with ADC cut off value ≤ 0.95 × 10−3 mm2/s. No statistically significant difference was found in ADC values between transitional cell carcinoma (TSC) and other cell types. Conclusion Combined use of DWI and HR T2WI provides more accurate urinary bladder cancer staging and prediction of aggressiveness of certain histologic grade (GIII lesions) using ADC values. 3 T scanners have the potential to achieve higher diagnostic capability in evaluation of urinary bladder cancer.