A comparison of endorectal MRI and TRUS in the local staging of prostate cancer with histopathological correlation

Introduction: This study assessed the staging accuracy of endorectal MRI, using a mid-field system (0.5 T) in patients with clinically localized prostate cancer and compared the results with TRUS. Patientsand methods: Twenty patients with clinically localized prostate cancer were prospectively staged with TRUS and endorectal MRI using a 0.5 T magnet. All patients subsequently underwent radical prostatectomy and the results of pre-operative staging were compared with the histological findings. Results: The sensitivity and specificity for diagnosing capsular penetration were 38% and 100%, respectively, for endorectal MRI and 23% and 86% for TRUS. The sensitivity and specificity for diagnosing seminal vesicle invasion were 100% and 94%, respectively, for endorectal MRI and 33% and 100% for TRUS. The overall staging accuracy for endorectal MRI was 75%. compared with 50% for TRUS. Conclusions: In comparison with TRUS, endorectal MRI with a 0.5 T magnet provides greater sensitivity and specificity for capsular penetration and increased sensitivity for seminal vesicle invasion.