Role of MRI in Staging Urinary Bladder Tumors

Author(s):

Asif Mehraj*, Arif Hameed, Saima Nanda, Baldev Singh Wazir and Mudasir A khan

Background: Accurate preoperative evaluation of proven bladder carcinoma is important because therapy depends on the clinical stage of the disease. Various imaging modalities have been used for such staging, and as such there is a need to look for the single best modality. Aim and objective: To determine the sensitivity, specificity and overall accuracy of MRI in staging urinary bladder carcinoma, and to evaluate its role in making comparison between superficial vs. invasive tumors and organ confined vs. non organ confined tumors. Material and Methods: This prospective study was undertaken on 25 patients of proven bladder carcinoma who were candidates for radical cystectomy. They were investigated in a sequential manner which included all routine investigations beside transabdominal ultrasonography, cystoscopy and biopsy (TUR / cystoscopic) and magnetic resonance imaging (MRI). Radical cystectomy was performed in all patients. MRI staging was correlated with the pathologic staging. Results: Analysis of our results revealed a highly significant (P<-0.001) MRI accuracy of 96% for deep muscle invasion, 84% accuracy for perivesical fat invasion and 84% accuracy of MRI detection of lymph node metastases. However, 88% accuracy of MRI for contiguous organ involvement was found to be of relatively lower significance (P<-0.05). Overall accuracy of MRI in the staging of bladder carcinoma was 60% with an overestimation of the tumor in 20% patients and an underestimation in 20% patients. Conclusion: MRI is an efficient non-invasive modality for imaging of bladder anatomy and bladder carcinoma. It has a high accuracy, sensitivity and specificity for differentiating invasive from noninvasive bladder carcinoma, and determining the involvement of adjacent organs. A larger prospective study is however, required for determining the exact role of MRI in the staging of bladder carcinoma.