Original Investigation T2 Star-weighted Angiography (SWAN) Allows to Concomitantly Assess the Prostate Contour While Detecting Fiducials Before MR-based Intensity-modulated Radiation Therapy in Prostate Carcinoma Pierre-Antoine Dirajlal, MD, Eva Jambon, MD, Agnes Albat-Esquirou, MD, Chloe Galmiche, MD, Jean-Christophe Bernhard, MD, PhD, Nicolas Grenier, MD, Thibaud Haaser, MD, PhD, François H. Cornelis, MD, PhD Purpose: To evaluate the performance of T2 star-weighted angiography (SWAN) to concomitantly assess the prostate contour while detecting fiducials before magnetic resonance (MR)-based intensity-modulated radiation therapy (IMRT) in prostate carcinoma. Materials and Methods: Forty patients (mean age: 73.1 ± 7.5 years; average Gleason score: 7 ± 1; average prostate-specific antigen: 14.7 ± 11.6 ng/mL) underwent MR and computed tomography imaging before fiducial-based IMRT. MR protocol included SWAN, T2- weighted (T2w) and diffusion-weighted imaging in a first group (n = 20) and SWAN, T2w and T2-star weighted imaging in a second group (n = 20). In group 1, the depiction of fiducials, image sharpness and visibility of prostate boundaries were independently evalu- ated by 2 readers on SWAN, T2w or diffusion-weighted images. In group 2, a similar evaluation was performed by 2 other readers on SWAN and T2-star images only. Depiction of fiducials was compared to computed tomography findings. Results: The median scores of visibility of prostate boundaries, image sharpness and depiction of fiducials by SWAN were above average to excellent for all readers. In group 1, readers correctly located 56 of 57 (98.2%) and 47 of 57 (82.5%) fiducials, respectively; and 50 of 51 (98%), and 48 of 51 (88.2%) fiducials in group 2, respectively. Conclusion: By allowing adequate visualization of the prostate boundaries and high depiction of fiducial markers concomitantly, SWAN might be used for treatment planning of IMRT. The use of this sequence might simplify the registration process and limit any errors associated with image fusion. Key Words: Prostate cancer; radiotherapy; treatment planning; fiducial; magnetic resonance imaging. © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved. INTRODUCTION I ntensity-modulated radiotherapy (IMRT) in prostate car- cinoma may potentially improve outcomes by creating sharp borders confining high dose to the prostate and leading to spare the surrounding organs (1–5). However, IMRT requires improved evaluation of the prostatic gland to individually determine the optimal treatment plan (6–8). To overcome the traditional limitations of computed tomog- raphy (CT)-based IMRT workflow, fiducial markers have been used to enable landmark-based alignment of magnetic resonance images (MRI) to the planning CT images (6–8). Acad Radiol 2017; ■:■■–■■ From the Department of Radiology, Pellegrin Hospital, Place Amélie Raba Léon, 33076 Bordeaux (P.-A.D., E.J., A.A.-E., C.G., N.G., F.H.C.); Department of Urology, Pellegrin Hospital, Bordeaux (J.-C.B.); Department of Oncology, St André Hospital, Bordeaux, France (T.H.); Department of Radiology, Tenon Hospital, 4 rue de la Chine, 75020 Paris (F.H.C.). Received February 22, 2017; revised July 24, 2017; accepted July 25, 2017. Addresss correspondence to: F.H.C. e-mail: cornelisfrancois@gmail.com © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.acra.2017.07.012 1 ARTICLE IN PRESS