title: MR perfusion imaging in Moyamoya Syndrome: potential implications for clinical evaluation of occlusive cerebrovascular disease.
abstract: OBJECTIVE
  Ischemic symptoms in patients with moyamoya syndrome (MMS) are usually due to hemodynamically mediated perfusion failure, and identification of abnormal tissue perfusion in these patients is therefore clinically important. Although dynamic susceptibility contrast (DSC) MRI can be used to study tissue perfusion, there are potential technical problems in MMS. This study investigates the scope and limitations of perfusion MRI in the clinical evaluation of such patients.
  
  
  METHODS
  Thirteen patients with bilateral MMS were studied with the use of structural, diffusion, and perfusion MRI. The DSC MRI data were analyzed both visually and by a quantitative regional analysis, and the relationship between perfusion status and clinical symptoms was investigated.
  
  
  RESULTS
  Extensive bilateral DSC MRI abnormalities were observed in all the patients. There was a very heterogeneous distribution of bolus arrival time. The areas of abnormality included the major arterial border zones in all cases, although these usually appeared normal on structural and diffusion MRI. Only the most clinically unstable patients had peak width (defined as time to peak minus bolus arrival time) >5 seconds on the quantitative regional analysis. Several technical limitations of perfusion quantification in MMS are described, as well as the implications of these limitations in patients with other forms of occlusive large-vessel disease.
  
  
  CONCLUSIONS
  The technical limitations of DSC MRI described in this study are important for the accurate interpretation of perfusion MRI in MMS. Despite these limitations, these preliminary findings suggest that the use of quantitative regional analysis of summary parameters may provide clinically useful information in patients with MMS.
authors.affiliation: Radiology and Physics Units, Institute of Child Health, University College London, UK. cfernan@ich.ucl.ac.uk
authors.forename: F
authors.initials: F
authors.lastname: Calamante
authors.forename: V
authors.initials: V
authors.lastname: Ganesan
authors.forename: F J
authors.initials: FJ
authors.lastname: Kirkham
authors.forename: W
authors.initials: W
authors.lastname: Jan
authors.forename: W K
authors.initials: WK
authors.lastname: Chong
authors.forename: D G
authors.initials: DG
authors.lastname: Gadian
authors.forename: A
authors.initials: A
authors.lastname: Connelly
mesh_terms: D000293:Adolescent; D002545:Brain Ischemia / Q000175:diagnosis* / Q000209:etiology; D016893:Carotid Stenosis / Q000150:complications / Q000175:diagnosis; D002560:Cerebrovascular Circulation / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D003097:Collateral Circulation; D003287:Contrast Media; D004058:Diffusion; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009072:Moyamoya Disease / Q000150:complications / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D003287:Contrast Media