title: Assessment of extracranial-intracranial bypass in Moyamoya disease using 3T time-of-flight MR angiography: comparison with CT angiography.
abstract: BACKGROUND
  To evaluate the value of time-of-flight MR angiography (TOF MRA) for the assessment of extracranial-intracranial (EC-IC) bypass in Moyamoya disease in comparison with computed tomography angiography (CTA).
  
  
  METHODS
  A consecutive series of 23 patients with Moyamoya disease were analyzed retrospectively. Twenty three patients underwent 25 procedures of extracranial-intracranial bypass. Cranial CTA was performed within one week after the surgery to assess bypass patency. Then TOF MRA was scanned within 24 h after CTA on a 3T MRI system. Using 5-point scales (0 = poor to 4 = excellent), two radiologists rated the image quality and vessel integrity of bypass for three segments (extracranial, trepanation, intracranial).
  
  
  RESULTS
  Image quality was high in both CTA and TOF MRA (mean quality score 3.84 ± 0.37 and 3.8 ± 0.41), without statistical difference (p = 0.66). Mean scores of TOF MRA with respect to bypass visualization were higher than CTA in the intracranial segment (p = 0.026). No significant difference of bypass visualization regarding the extracranial and trepanation segments was found between TOF MRA and CTA (p = 0.66 and p = 0.34, respectively). For the trepanation segment, TOF MRA showed pseudo lesions in 2 of all 25 cases.
  
  
  CONCLUSIONS
  3T TOF MRA, a non-contrast technique not exposing the patients to radiation, proved to be at least equal to CTA for the assessment of EC-IC bypass, and even superior to CTA with respect to the intracranial segment. In addition, readers should be aware of a potential overestimation showing focal pseudo lesions of the bypass at the trepanation segment in TOF MRA.
authors.affiliation: Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
authors.forename: Rongfeng
authors.initials: R
authors.lastname: Qi
authors.affiliation: Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
authors.forename: Changsheng
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
authors.forename: Song
authors.initials: S
authors.lastname: Luo
authors.affiliation: Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Ni
authors.affiliation: Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D002533:Cerebral Angiography / Q000379:methods*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D002548:Cerebral Revascularization; D002560:Cerebrovascular Circulation; D002648:Child; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D009072:Moyamoya Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014654:Vascular Patency; D055815:Young Adult
keywords: Moyamoya disease; computed tomography angiography; extracranial-intracranial bypass; magnetic resonance angiography