www.kjurology.org http://dx.doi.org/10.4111/kju.2011.52.8.572 Investigative Urology The Clinical Value of Performing an MRI before Prostate Biopsy Myung Sun Choi, Yong Sun Choi, Byung Il Yoon, Su Jin Kim, Hyuk Jin Cho, Sung Hoo Hong, Ji Youl Lee, Tae-Kon Hwang, Sae Woong Kim Department of Urology, The Catholic University of Korea, College of Medicine, Seoul, Korea Purpose: Prostate cancer foci have a characteristic feature in magnetic resonance imag- ing (MRI). We aimed to assess the clinical value of MRI before prostate biopsy in prostate cancer detection. Materials and Methods: From March 2009 to June 2010, 154 patients were enrolled in this study. A total of 51 patients with a clinical suspicion of prostate cancer underwent prostate MRI by a 3T scanner before transrectal ultrasound (TRUS)-guided biopsies. A total of 103 patients with a clinical suspicion of prostate cancer underwent prostate MRI after biopsies. The sensitivity, specificity, and positive predictive value (PPV) were evaluated. In addition, tumor location of pathologic findings and ADC mapping on MRI were matched and compared. Results: The sensitivity of MRI before and after biopsy was 84.8% and 92.4%, respectively. The PPV of MRI before and after biopsy was 75.7% and 92.4%, respectively. The MRI location match percentage before and after biopsy was 89.3% and 94.1%, respectively. Conclusions: Compared with other previous reports, our results show that the prostate cancer detection sensitivity of MRI is on the rise. Furthermore, MRI before prostate biopsy can provide more information by which to identify prostate cancer during pros- tate biopsy and thus reduce the false-negative rate. Key Words: Biopsy; MRI; Prostate cancer This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Article History: received 28 June, 2011 accepted 14 July, 2011 Corresponding Author: Sae Woong Kim Department of Urology, Seoul St. Mary's Hospital, The Catholic University of Korea, College of Medicine, 505, Banpo-dong, Seocho-gu, Seoul 137-701, Korea TEL: +82-2-2258-6226 FAX: +82-2-599-7839 E-mail: ksw1227@catholic.ac.kr INTRODUCTION Prostate cancer is the third leading cause of death after lung cancer and colorectal cancer in Europe. The incidence of prostate cancer is 30 in 100,000 males [1]. According to the American Cancer Society, prostate cancer is the third leading cause of death among all cancer deaths in males, and in 2007, a total of 218,890 new prostate cancer patients were diagnosed and 27,050 patients died of prostate cancer [2]. As the number of prostate cancer patients has in- creased, the diagnosis, assessment of disease stage, and treatment methods have improved greatly. 　Transrectal prostate biopsy is a useful method for pros- tate cancer diagnosis and lesion site assessment [3]. However, the procedure entails discomfort and has risks for hemorrhage and prostatitis afterwards. In addition, if the cancer lesions are small, biopsy may not be performed Korean Journal of Urology Ⓒ The Korean Urological Association, 2011 accurately [4-6]. 　Magnetic resonance imaging (MRI) is a useful tool for prostate cancer diagnosis and disease staging workup. Particularly, at present, it is widely used to assess the loca- tion and border of tumors as well as to determine the level of infiltration to adjacent tissues. Nevertheless, if MRI is performed after transrectal prostate biopsy, due to hemor- rhaging within tissues, it may be difficult to assess the loca- tion of cancer lesions and to determine the range and border of the tumor; consequently, the size of the lesion may be un- derestimated or overestimated [7-9]. However, in the past 20 years, with the introduction of diffusion-weighted imag- ing, dynamic contrast-enhanced MRI, and MR spectro- scopy, prostate cancer can be diagnosed more accurately and effectively [10-17]. 　In the present study, we examined whether MRI that was performed before prostate biopsy is of help in the diag- 572 Korean J Urol 2011;52:572-577