title: Neovascularization precedes occlusion in moyamoya disease: angiographic findings in 172 pediatric patients.
abstract: BACKGROUND
  Both basal collaterals (BC) and cortical microvascularization (CM) on angiography have been suggested as moyamoya disease (MMD)-specific findings; however, it is unknown whether the vascular network represents compensatory mechanisms for vascular occlusion or aberrant active neovascularization.
  
  
  METHODS
  We investigated the grade of antegrade MCA flow, the degree of BC, and the presence of CM on conventional angiography in relation to disease severity in pediatric MMD. CM was defined as enlarged and winding distal cortical arteries and categorized into anterior or posterior CM depending on their sources. Findings from basal and acetazolamide stress brain perfusion SPECT studies were also evaluated.
  
  
  RESULTS
  A total of 172 pediatric patients with MMD were enrolled in this study. As the severity of MMD increased, the grade of antegrade MCA flow gradually diminished. While the degree of BC peaked at Suzuki stage 3-4, CM was frequently observed at early MMD stages. About two-thirds of hemispheres with normal antegrade MCA flow on angiography and normal perfusion status on SPECT had anterior and/or posterior CM. Both anterior and posterior CM gradually decreased with the advancement of MMD.
  
  
  CONCLUSIONS
  Our findings from a large cohort of angiographically confirmed pediatric MMD patients indicate that neovascularization may occur before significant hemodynamic impairment in MMD.
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Suk Jae
authors.initials: SJ
authors.lastname: Kim
authors.forename: Tae Ok
authors.initials: TO
authors.lastname: Son
authors.forename: Keon Ha
authors.initials: KH
authors.lastname: Kim
authors.forename: Pyoung
authors.initials: P
authors.lastname: Jeon
authors.forename: Seung Hyup
authors.initials: SH
authors.lastname: Hyun
authors.forename: Kyung-Han
authors.initials: KH
authors.lastname: Lee
authors.forename: Je Young
authors.initials: JY
authors.lastname: Yeon
authors.forename: Jong-Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Seung-Chyul
authors.initials: SC
authors.lastname: Hong
authors.forename: Hyung Jin
authors.initials: HJ
authors.lastname: Shin
authors.forename: Oh Young
authors.initials: OY
authors.lastname: Bang
mesh_terms: D000086:Acetazolamide; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D002317:Cardiovascular Agents; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D055806:Microvessels / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D009072:Moyamoya Disease / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D009389:Neovascularization, Pathologic; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013312:Stress, Physiological; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D002317:Cardiovascular Agents; D000086:Acetazolamide