Dynamic Contrast-Enhanced MRI and Diffusion-Weighted MRI for the Diagnosis of Bladder Cancer.

摘要

It is estimated by the American Cancer Society that there will be about 72,570 newly diagnosed cases of bladder cancer (about 54,610 in men and 17,960 in women) and about 15,210 (about 10,820 in men and 4,390 in women) deaths from bladder cancer in 2013. Early detection and accurate staging of bladder cancer are crucial to stratify the treatment plan and ensure the best patient prognosis. In the treatment of bladder cancer patients with chemotherapy, it is important to predict a patient as a chemotherapeutic responder or non-responder to both maximize the patient benefit from chemotherapy and avoid unnecessary delay of cystectomy. However, these clinical needs in bladder cancer management are still unmet in clinical tests, cystoscopy, and bladder imaging. This study is aimed at evaluating the abilities of 3T dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted MRI (DWI) to improve the detection and staging and to enable the prediction of chemotherapeutic response in bladder cancer.;A total of fifty-three patients were enrolled in the study. Different inclusion criteria were established for three different types of data assessment: (1) Improving bladder cancer detection with DCE-MRI; (2) early prediction of chemotherapeutic response in bladder cancer with DCE-MRI; and (3) quantitative assessment of T staging of bladder cancer with DWI.;Thirty-six patients were included in the analysis of DCE-MRI for bladder cancer detection. The results demonstrated that the maps of DCE-MRI pharmacokinetic parameters can better visualize small malignant tumors and the tumors within bladder wall thickenings to improve the detection of bladder cancer compared to conventional T2-weighted MRI alone. Twenty-five patients were included in the analysis of DCE-MRI for early prediction of chemotherapeutic response in bladder cancer. Using k-means clustering of DCE-MRI pharmacokinetic parameters, each bladder tumor was divided into three clusters of different microcirculation characteristics, thus, different chemotherapeutic responses. These differences enabled to classify a bladder cancer patient as a responder or a non-responder at the mid-cycle time point of therapy. Eighteen patients were included in the DWI data for T staging of bladder cancer. The ADC referenced to the individual bladder urine was found to be associated with the tumor stage. The group of stage T1 or lower (Ta, Tis, T1) had a significantly lower relative ADC than the group of stage T2 (P<0.03), stage T3 (P<0.05), and stage T4 (P<0.03). The relative ADC of the group of stage T2 was also found to be significantly lower than that of the group of stage T3 (P<0.03) and stage T4 (P<0.05).;In conclusion, 3T MRI with functional DCE-MRI and DWI can substantially improve the diagnosis of bladder cancer by enabling better visualization of malignant bladder tumors and the quantitative assessment to classify tumor stage and chemotherapeutic response.