Utility of quantitative MRI metrics for assessment of stage and grade of urothelial carcinoma of the bladder: preliminary results.

OBJECTIVE. The purpose of this study was to assess associations between quantitative MRI metrics and pathologic indicators of aggressiveness of urothelial carcinoma of the bladder. MATERIALS AND METHODS. In this retrospective biinstitutional study, 37 patients (28 men and nine women; mean age, 73 ± 12 years) who underwent pelvic MRI including diffusion-weighted imaging (b values 0, 400, and 800 s/mm2) and T2-weighted imaging before transurethral resection or cystectomy for urothelial carcinoma of the bladder were identified. Tumor diameter (measured on T2-weighted imaging), normalized T2 signal intensity (to muscle; hereafter labeled normalized T2) and apparent diffusion coefficient (ADC) were measured for all tumors. Mann-Whitney test and receiver operating characteristic analyses were used to identify associations between these metrics and histopathologic tumor stage and grade. RESULTS. Thirty-seven tumors were assessed (mean size, 35 ± 23 mm; range 8–88 mm). At histopathologic analysis, 16 of 37 (43%) ...