Role of magnetic resonance imaging in bladder cancer: current status and emerging techniques.

OBJECTIVES: To evaluate the current status of magnetic resonance imaging (MR) as a staging tool for bladder cancer. To investigate the role of MR in assessing chemotherapeutic response in bladder cancer patients. PATIENTS AND METHODS: A Pubmed/MEDLINE search was conducted to identify original articles, review articles, and editorials regarding the use of MR in bladder cancer.
RESULTS: Contrast-enhanced MR and diffusion weighted MR (DW-MRI) can likely distinguish between non-muscle invasive bladder cancer and muscle invasive cancer with >80% accuracy. Some advantages of DW-MRI are the differentiation of benign versus malignant tissue involvement without the need for intravenous contrast, and the possibility of obtaining information on histologic grade and T stage. Traditional MR sequence have low sensitivity for identifying small lymph node metastases but MR lymphography (MRL) using ultra-small paramagnetic iron oxide (USPIO) may enhance their detectin. There may be a role for DW-MRI in the evaluation of chemotherapeutic response in bladder cancer patients.
CONCLUSION: To date, sample sizes and study designs are insufficient to clearly establish the role of MR in bladder cancer management, and to this end, well designed prospective trials are needed.