title: Is Quasi-moyamoya Disease a Uniform Disease Entity? A Three-Dimensional Constructive Interference in Steady State Imaging Study.
abstract: BACKGROUND
  Quasi-moyamoya disease (MMD) or moyamoya syndrome is based on various underlying diseases and radiologically simulates MMD, but its disease entity is still unclear. Recent studies have proven specific shrinkage of the involved arteries in MMD. Using 3-dimensional constructive interference in steady state (3D-CISS), therefore, this study aimed to analyze the outer diameter of the involved arteries in quasi-MMD.
  
  
  METHODS
  This study included 9 patients with quasi-MMD (unilateral type, n = 2; bilateral type, n = 7). Using 3D-CISS, the outer diameter was quantified in the internal carotid artery distal to the posterior communicating artery (C1), the horizontal portion of the middle and anterior cerebral arteries (M1 and A1, respectively), and the basilar artery. Control values were obtained from 17 healthy subjects.
  
  
  RESULTS
  In 7 of 9 patients, the outer diameters of C1, M1, and A1 were significantly smaller than those of the controls. On the other hand, the values were normal in other 2 patients. There was no significant difference in the underlying disorders between the 2 groups. All 3 pediatric patients are categorized into the arterial shrinkage group, but 2 of 6 adult patients were not.
  
  
  CONCLUSIONS
  These findings strongly suggest that quasi-MMD is not a uniform disease entity and includes at least 2 pathophysiologically different groups: the arterial shrinkage group and the nonarterial shrinkage group. A certain subgroup of MMD patients may be misdiagnosed as quasi-MMD because of the patients' comorbid disorders and mixed up with the patients who present angiographic findings similar to MMD in spite of the lack of arterial shrinkage.
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan. Electronic address: s.yamamoto1007@gmail.com.
authors.forename: Shusuke
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Koh
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan.
authors.forename: Daina
authors.initials: D
authors.lastname: Kashiwazaki
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Akioka
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Kuwayama
authors.affiliation: Department of Radiology, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan.
authors.forename: Kyo
authors.initials: K
authors.lastname: Noguchi
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kuroda
mesh_terms: D000293:Adolescent; D000328:Adult; D000369:Aged, 80 and over; D001488:Basilar Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D016022:Case-Control Studies; D002533:Cerebral Angiography / Q000379:methods*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008297:Male; D009072:Moyamoya Disease / Q000145:classification / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D016896:Treatment Outcome
keywords: 3D-CISS; MRI; diagnosis; outer diameter; quasi-moyamoya disease