title: Hemodynamic Analysis of Endoleaks After Endovascular Abdominal Aortic Aneurysm Repair by Using 4-Dimensional Flow-Sensitive Magnetic Resonance Imaging.
abstract: BACKGROUND
  An endoleak is a common complication of endovascular abdominal aortic aneurysm repair (EVAR), and it can be associated with aneurysmal growth. This pilot study used 4-dimensional flow-sensitive magnetic resonance imaging (4D-flow) to assess the hemodynamics of different types of endoleaks (I-IV).
  
  
  RESULTS
  Magnetic resonance angiography, 4D-flow, and computed tomography angiography (CTA) were performed in 31 patients after nitinol-based stent-graft deployment. With 4D-flow, the 3D streamlines of endoleaks appear as integrated traces along the instantaneous velocity vector field that are color-coded according to the local velocity magnitude of the leak. The 4D-flow analysis identified endoleaks in 18 patients (58.1%), whereas CTA identified endoleaks in 13 patients (41.9%). The 4D-flow analysis created a characteristic image of each type of endoleak. Among patients with endoleaks, 4D-flow identified concomitant multiple endoleaks in 7 (39%) patients, and it further differentiated type II endoleaks from type IIa endoleaks (to-and-fro biphasic flow pattern from a branch vessel) and from type IIb endoleaks (monophasic flow pattern with a connection between the inflow and outflow branches).
  
  
  CONCLUSIONS
  The 4D-flow analysis was more sensitive than CTA for detecting an endoleak, and it could subclassify type II endoleaks. In addition, 4D-flow differentiated between concomitant endoleak types in a single patient. (Circ J 2016; 80: 1715-1725).
authors.affiliation: Second Department of Surgery, Hamamatsu University School of Medicine.
authors.forename: Mayu
authors.initials: M
authors.lastname: Sakata
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Takehara
authors.forename: Kazuto
authors.initials: K
authors.lastname: Katahashi
authors.forename: Masaki
authors.initials: M
authors.lastname: Sano
authors.forename: Kazunori
authors.initials: K
authors.lastname: Inuzuka
authors.forename: Naoto
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Masataka
authors.initials: M
authors.lastname: Sugiyama
authors.forename: Harumi
authors.initials: H
authors.lastname: Sakahara
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Wakayama
authors.forename: Marcus T
authors.initials: MT
authors.lastname: Alley
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Konno
authors.forename: Naoki
authors.initials: N
authors.lastname: Unno
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D001027:Aortography / Q000379:methods; D001783:Blood Flow Velocity; D057867:Endoleak / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D014057:Tomography, X-Ray Computed / Q000379:methods*