Comparison of dynamic contrast-enhanced and diffusion weighted magnetic resonance image in staging and grading of carcinoma bladder with histopathological correlation

ABSTRACT

Bladder cancer is the second most common neoplasm of the urinary tract worldwide. Dynamic contrast-enhanced and diffusion-weighted MRI has been introduced in clinical MRI protocols of bladder cancer because of its accuracy in staging and grading. To evaluate and compare accuracy of Dynamic contrast enhanced [DCE] and Diffusion weighted [DW] MRI for preoperative T staging of urinary bladder cancer and find correlation between apparent diffusion coefficient [ADC] and maximum enhancement with histological grade. Sixty patients with bladder cancer were included in study. All patients underwent Magnetic Resonance Imaging [MRI] on a 1.5-T scanner with a phased-array pelvic coil. MR images were evaluated and assigned a stage which was compared with the histolopathological staging. ADC value and maximum enhancement curve were used based on previous studies. Subsequently histological grade was compared with MR characteristics. The extent of agreement between the radiologic staging and histopathological staging was relatively greater with the DW-MRI [?=0.669] than DCE-MRI [?=0.619]. The sensitivity, specificity, and accuracy are maximum and similar for stage T4 tumors in both DCEMRI [100.0, 96.2 and 96.7] and DW-MRI [100.0, 96.2 and 96.7] while minimum for stage T2 tumors - DCEMRI [83.3, 72.2, and 76.7] and DWI-MRI [91.7, 72.2, and 80]. MRI is an effective tool for determining T stage and histological grade of urinary bladder cancers. Stage T2a and T2b can be differentiated only by DCE-MRI. Results were more accurate when both ADC and DCE-MRI were used together and hence a combined approach is suggested