A comparison of endorectal magnetic resonance imaging and transrectal ultrasonography in the local staging of prostate cancer with histopathological correlation

Objective To assess the staging accuracy of endorectal magnetic resonance imaging (MRI), using a mid-field system, in patients with clinically localized prostate cancer and to compare the results with transrectal ultrasonography (TRUS). Patients and 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. Conclusion Compared with TRUS, endorectal MRI with a 0.5 T magnet provided greater sensitivity and specificity for capsular penetration and increased sensitivity for seminal vesicle invasion.