title: Endoleak detection after endovascular aneurysm repair using unenhanced MRI with flow suppression technique: Feasibility study in comparison with contrast-enhanced CT.
abstract: OBJECTIVE
  To evaluate the feasibility of unenhanced motion-sensitized-driven equilibrium (MSDE)-prepared balanced turbo field echo (BTFE) sequences for detecting endoleaks after endovascular aneurysm repair (EVAR).
  
  
  METHODS
  Forty-six patients treated with EVAR for aortic and/or iliac arterial aneurysms underwent contrast-enhanced CT and MSDE-prepared BTFE sequences with and without flow suppression. Two independent observers reviewed these sequences and their subtraction images and assigned confidence levels for detecting endoleaks. Relative contrast values were calculated by dividing signal intensities by those of paraspinal muscles. CT provided the reference standard.
  
  
  RESULTS
  CT showed types I and II endoleaks in one and ten patients, respectively. Areas under receiver operating characteristic curves were 0.92 and 0.97 for observers 1 and 2, respectively. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value of both observers were 91 (10/11), 91(32/35), 91 (42/46), 77 (10/13) and 97 % (32/33), respectively. Relative contrast values of endoleaks and flowing blood significantly decreased by flow suppression on MSDE-prepared BTFE images (P = 0.002 and P < 0.0001 respectively), and were significantly higher than those of the excluded aneurysms on subtraction images (P = 0.003 and P = 0.001, respectively).
  
  
  CONCLUSIONS
  Unenhanced MSDE-prepared BTFE sequences are feasible for detecting endoleaks.
  
  
  CONCLUSIONS
  • Flow suppression significantly reduces endoleak signals on MSDE-prepared BTFE images. • Subtraction images of MSDE-prepared BTFE sequences ± flow suppression demonstrate endoleaks. • MSDE-prepared BTFE sequences indicate high diagnostic values (>90 %) except PPV (77 %). • MSDE-prepared BTFE sequences need further refinement to reduce false positives. • Endoleaks can be detected without contrast injection using MSDE-prepared BTFE sequences.
authors.affiliation: Department of Radiology Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan. moriken@md.tsukuba.ac.jp.
authors.forename: Kensaku
authors.initials: K
authors.lastname: Mori
authors.affiliation: Department of Radiology Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Saida
authors.affiliation: Department of Cardiovascular Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Fujio
authors.initials: F
authors.lastname: Sato
authors.affiliation: Department of Radiology, Hitachi General Hospital, 2-1-1 Jonancho, Hitachi, Ibaraki, 317-0077, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Uchikawa
authors.affiliation: Department of Radiology, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Konishi
authors.affiliation: Department of Radiology, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Ishiguro
authors.affiliation: Department of Radiology, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hiyama
authors.affiliation: Department of Radiology, Ibaraki Prefectural Central Hospital, 6528 Koibuchi, Kasama, Ibaraki, 309-1793, Japan.
authors.forename: Sodai
authors.initials: S
authors.lastname: Hoshiai
authors.affiliation: Department of Radiology Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Okamoto
authors.affiliation: Department of Radiology Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Nasu
authors.affiliation: Department of Radiology Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Minami
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D003287:Contrast Media; D057867:Endoleak / Q000000981:diagnostic imaging*; D057510:Endovascular Procedures; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Aortic aneurysm; Endoleak; Endovascular procedures; Iliac aneurysm; Magnetic resonance imaging