title: Multi-echo gradient recalled echo imaging of the pelvis for improved depiction of brachytherapy seeds and fiducial markers facilitating radiotherapy planning and treatment of prostatic carcinoma.
abstract: OBJECTIVE
  MR localization of implanted devices for radiotherapy (RT) in prostatic carcinoma is critical for treatment planning. This clinical note studies the application of a multi-echo gradient recalled echo (GRE) pulse sequence with sum of squares echo combination (ME GRE) to enhance detection of seeds and fiducials.
  
  
  METHODS
  Fifteen patients who underwent MRI using fast spin echo (FSE), single-echo and ME GRE over a 9-month period were retrospectively evaluated by two readers who assessed overall image quality, depiction of seeds/fiducials and image sharpness using a 5-point scale (1 = poor, 2 = suboptimal, 3 = adequate, 4 = above average, 5 = excellent). Image scores were compared using the Wilcoxon sign rank test.
  
  
  RESULTS
  In all 15 patients, both readers rated the depiction of seeds/fiducials with ME GRE as excellent. In all 15 patients, overall image quality and image sharpness with ME GRE was rated as excellent by reader 1. In 12/15 patients, overall image quality and image sharpness with ME GRE was rated as excellent and in the other patients above average by reader 2. There was a difference in depiction of seeds/fiducials comparing GRE to FSE (P < 0.001) and ME to single echo GRE (P < 0.001). Overall image quality and sharpness was higher with ME compared with single echo GRE (P < 0.001) and similar to FSE (P = 0.26 and P = 0.16).
  
  
  CONCLUSIONS
  Multi-echo GRE provides better detection of implanted seeds and fiducial markers when compared with both FSE and single-echo GRE potentially improving RT treatment planning for prostate carcinoma.
authors: The Ottawa Hospital, The University of Ottawa, Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors: Nicola
authors: N
authors: Schieda
authors: Leonard
authors: L
authors: Avruch
authors: Wael M
authors: WM
authors: Shabana
authors: Shawn Christopher
authors: SC
authors: Malone
mesh_terms: D001918:Brachytherapy / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D057918:Fiducial Markers; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D010388:Pelvis; D011467:Prostate / Q000473:pathology; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012680:Sensitivity and Specificity
keywords: Brachytherapy; Fiducial; Multi-echo Gradient Recalled Echo; Prostate Cancer; Radiotherapy; Treatment planning