title: Noninvasive visualization of endoleaks after endovascular aortic aneurysm repair through unenhanced MRI with motion-sensitized driven equilibrium preparation: Phantom experiments.
abstract: OBJECTIVE
  To optimize imaging parameters for balanced turbo field echo (BTFE) sequence combined with motion-sensitized driven equilibrium (MSDE) preparation for endoleak detection and type classification in phantom experiments.
  
  
  METHODS
  We prepared four phantoms: a pulsatile flow generator with an aortic aneurysm model simulating no endoleak, and a type-1, type-2, and type-3 endoleak. Throughout the experiments, MSDE-BTFE images with and without flow suppression were obtained at 1.5 T and subtraction images were used for image evaluation. The no-endoleak phantom was imaged using different MSDE-BTFE sequences to optimize the k-space trajectory and evaluate the use of electrocardiogram gating. The relative contrast between flowing saline and background was calculated. Then all phantoms were imaged to determine the optimal velocity encoding (VENC) for endoleak detection and type classification. Three independent observers performed the image evaluation. Consistencies between the interpreted and true results were analyzed using kappa statistics.
  
  
  RESULTS
  The 3D low-high k-space trajectory with electrocardiogram gating provided the highest relative contrast. Low VENCs of 2-10 cm/s and high VENCs of 20 cm/s showed perfect consistency in endoleaks detection and type classification, respectively.
  
  
  CONCLUSIONS
  MSDE-BTFE sequences of appropriate VENCs has potential for endoleak detection and type classification, without contrast material.
authors.affiliation: Department of Radiology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan. saida_sasaki_tsukasa@yahoo.co.jp
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Saida
authors.forename: Kensaku
authors.initials: K
authors.lastname: Mori
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yabe
authors.forename: Masashi
authors.initials: M
authors.lastname: Shindo
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Nasu
authors.forename: Masanari
authors.initials: M
authors.lastname: Shiigai
authors.forename: Hideto
authors.initials: H
authors.lastname: Takahashi
authors.forename: Manabu
authors.initials: M
authors.lastname: Minami
mesh_terms: D001014:Aortic Aneurysm / Q000150:complications / Q000473:pathology* / Q000601:surgery*; D003287:Contrast Media; D057867:Endoleak / Q000209:etiology* / Q000473:pathology*; D057510:Endovascular Procedures / Q000009:adverse effects*; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods*; D009038:Motion; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media
keywords: balanced turbo field echo sequence; endoleak; endovascular aortic aneurysm repair; motion-sensitized driven equilibrium preparation; phantom experiments