Preoperative Detection and Localization of Accessory Pudendal Artery with Contrast-enhanced MR Angiography

Abstract

Purpose: To evaluate the diagnostic performance of contrast material-enhanced magnetic resonance (MR) angiography for preoperative detection and localization of accessory pudendal arteries (APAs) in patients with prostate cancer. Materials and Methods: This prospective study was approved by the institutional review board, and informed consent was obtained. Between July 2007 and December 2010, 127 patients underwent contrast-enhanced MR angiography following prostate MR imaging at 3.0 T before robot-assisted laparoscopic radical prostatectomy (RALP). APAs were defined as any arteries located in the periprostatic region and anastomosed with the common penile artery or its branches; they were then subclassified into lateral and apical APAs. For detecting and localizing APAs, MR angiograms were evaluated prospectively by one reader and retrospectively by two independent blinded readers. Diagnostic performance was determined on a per-patient basis by using surgical findings as the reference standard. In addition, the origin of APAs identified at both surgery and contrast-enhanced MR angiography was determined by consensus of two retrospective readers. Interreader agreements were assessed by using k statistics. Results: At surgery, 19 APAs (seven right apical, three left apical, four right lateral, and five left lateral) were detected in 16 patients, and 16 of these APAs were localized in 13 patients at preoperative contrast-enhanced MR angiography. Prospectively, sensitivity, specificity, and accuracy of contrast-enhanced MR angiography for the localization of APAs were 81.3%, 93.7%, and 92.1%, while retrospectively they were 87.5%, 91.9%, and 91.3% for reader 2 and 75.0%, 90.1%, and 88.2% for reader 3, respectively. Overall interreader agreement was substantial (k = 0.795). Nine and seven APAs originated from the obturator artery and the inferior vesical artery, respectively. Conclusion: Contrast-enhanced MR angiography can be used for the preoperative detection of APAs in patients with prostate cancer.