MR imaging of bladder neoplasms: correlation with pathologic staging

This retrospective study describes the accuracy of magnetic resonance (MR) imaging in determination of local disease extent in 34 examinations performed for evaluation of primary or recurrent bladder carcinoma. The 34 examinations were carried out in 29 patients (17 men, 12 women, aged 34-89 years). All studies were followed within 30 days by surgical and pathologic evaluation. Images were interpreted by two radiologists unaware of clinical or pathologic findings. MR imaging staging conformed to the TNM system of the International Union Against Cancer (IUAC). Pathologic evaluation showed bladder neoplasms in all cases; three patients' pathologic specimens contained two or more histologic types of tumors. MR imaging staging of the depth of tumor invasion was correct in 85% of examinations. Sensitivity of MR imaging for detection of deep muscle invasion was 97%, specificity 83%, and accuracy 94%. Sensitivity of MR imaging for detection of extravesical tumor extension was 95%, specificity 100%, and accuracy 97%. Sensitivity for detection of pelvic lymph node metastases was 50%, specificity 100%, and accuracy 82%. Our population included many patients with locally advanced disease. This pattern reflects standards of clinical practice by which superficial lesions are staged and resected endoscopically, and deeply invasive tumors are imaged prior to radical surgery.