Multiparametric 3-T MRI for Differentiating Low-Versus High-Grade and Category T1 Versus T2 Bladder Urothelial Carcinoma

Abstract

OBJECTIVE. The purpose of this study was to determine an optimal multiparametric MRI protocol for characterizing tumors of low versus high grade and differentiating tumors as T1 versus T2 for preoperative staging of bladder urothelial carcinoma. SUBJECTS AND METHODS. Thirty-nine patients underwent MRI within 1 week before surgery. Three image sets-T2-weighted plus diffusion-weighted MRI (DWI), T2-weighted plus dynamic contrast-enhanced MRI (DCE-MRI), and T2-weighted plus DCEMRI plus DWI-were independently interpreted by two readers at 2-week intervals. ROC curves were plotted for both readers to compare the diagnostic efficacy of the three sets for detrusor muscle invasion for each reader, and the areas under the ROC curve were compared by use of the Bonferroni test. The apparent diffusion coefficient (ADC) values were correlated with histopathologic grade. RESULTS. A total of 49 category T1 and T2 lesions were analyzed. The average ADC of 11 low-grade tumors (1.141 ± 0.164 × 10(-3) mm(2)/s) was significantly (p < 0.05) higher than that of 20 high-grade malignant tumors (0.766 ± 0.091 × 10(-3) mm(2)/s). Neither reader considered T1 tumors as probably having muscle invasion (category T2) in the T2-weighted plus DWI image sets or the T2-weighted plus DWI plus DCE-MRI image sets. Using the T2-weighted plus DCE-MRI sets, the two readers overstaged 13 and 15 of 36 tumors by misdiagnosing category T1 as T2. With the cutoff ADC value of 0.899 × 10-3 mm(2)/s, the sensitivity and specificity for differentiating high- and low-grade bladder urothelial carcinoma were 100% and 95%. CONCLUSION. Multiparametric MRI with T2-weighted plus DWI plus DCE technique is the optimal protocol for preoperative staging of organ-confined bladder urothelial carcinoma. The ADC of low-grade tumors is significantly higher than that of high-grade tumors with 100% sensitivity and 95% specificity at a cutoff ADC value of 0.899 mm(2)/s.

Assessment of histological differentiation in gastric cancers using whole-volume histogram analysis of apparent diffusion coefficient maps

“…The use of a volume of interest (VOI) covering the entire lesion reduces the sampling error and improves the reproducibility of quantitative analysis. Whole‐volume histogram analysis of ADC maps has been successful in evaluating the histological grade, TNM staging, aggressiveness, and therapeutic response in rectal and bladder cancers . Therefore, the purpose of this study was to investigate the role of histogram analysis of ADC tumor volume maps in the assessment of histological differentiation of gastric cancer.…”

Update on multiparametric MRI of urinary bladder cancer

“…Interestingly, the ADC value may also be useful for determining tumor grade. The ADC value of low‐grade bladder tumors may be significantly higher than that of high‐grade tumors …”

“…11 Multiparametric magnetic resonance imaging (mp-MRI) of the bladder has reemerged as a noninvasive tool that can help assess the local stage and grade of bladder cancer with relatively high accuracy. [12][13][14][15][16][17] mp-MRI consists of highresolution T 2 -weighted (T 2 W) images, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging. 16 mp-MRI can demonstrate tumor growth into the bladder detrusor muscle, peri-vesical extension, and can also assess regional nodes and pelvic metastases.…”

DCE-MRI, DW-MRI, and MRS in Cancer

“…133 An ongoing multicenter trial in Australia is focusing on the prospective evaluation of quantitative mpMRI (ADC, K trans , k ep ) to stratify patients and guide radiation dosing. 134 The combination of T 2 -w + DW-MRI + DCE-MRI has been shown to be of benefit for distinguishing low- from high-grade bladder cancers (100% sensitivity, 95% specificity in 49 T1 and T2 lesions), 135 while the combination of wash-in and wash-out ratios on DCE-MRI together with ADC has been shown to be useful in renal clear cell cancers wherein higher Fuhrman tumor grades had lower parenchymal wash-in indices and lower ADCs than low-grade lesions. 136 There has been less demand for mpMRI for detecting and grading other cancers, as single parameters often suffice or treatment paradigms do not warrant the inclusion of complex methodology in the patient's diagnostic pathway.…”