title: A preliminary study of brain macrovascular reactivity in impaired glucose tolerance and type-2 diabetes: Quantitative internal carotid artery blood flow using magnetic resonance phase contrast angiography.
abstract: The aims of this study were (1) to examine cerebrovascular autoregulation in subjects with impaired glucose tolerance and type 2 diabetes and (2) to clarify whether cardiovascular autonomic nerve function is associated with abnormal cerebrovascular autoregulation.
  
  
  
  Totally, 46 subjects were recruited (12 = impaired glucose tolerance, 17 = type 2 diabetes and 17 = healthy volunteers). Arterial blood flow was assessed within the internal carotid artery at baseline and 20 min after intravenous pharmacological stress (1 g acetazolamide), using quantitative magnetic resonance phase-contrast angiography. Internal carotid artery vascular reactivity and pulsatility index was determined. All subjects underwent baroreceptor reflex sensitivity assessment.
  
  
  
  Subjects with impaired glucose tolerance and type 2 diabetes had significantly lower internal carotid artery vascular reactivity [40.2%(19.8) and 41.5%(18.7)], respectively, compared with healthy volunteers [57.0%(14.2); analysis of variance, p = 0.02]. There was no significant difference in internal carotid artery vascular reactivity between type 2 diabetes and impaired glucose tolerance groups (p = 0.84). There was a significant positive correlation between baroreceptor reflex sensitivity (low frequency:high frequency) with cardiac rhythm variability (ρ = 0.47, p = 0.04) and PI (ρ = 0.46, p = 0.04).
  
  
  
  We have demonstrated significant cerebrovascular haemodynamic abnormalities in subjects with type 2 diabetes and impaired glucose tolerance. This was associated with greater sympathovagal imbalance. This may provide an important mechanistic explanation for increased risk of cerebrovascular disease in diabetes. It also highlights that these abnormalities may already be present in prediabetes.
authors.affiliation: Department of Human Metabolism, The University of Sheffield, Sheffield, UK d.selvarajah@sheffield.ac.uk.
authors.forename: Dinesh
authors.initials: D
authors.lastname: Selvarajah
authors.affiliation: Academic Unit of Radiology, The University of Sheffield, Sheffield, UK.
authors.forename: Timothy
authors.initials: T
authors.lastname: Hughes
authors.affiliation: Academic Unit of Radiology, The University of Sheffield, Sheffield, UK.
authors.forename: Josie
authors.initials: J
authors.lastname: Reeves
authors.affiliation: Academic Unit of Radiology, The University of Sheffield, Sheffield, UK.
authors.forename: Elaine
authors.initials: E
authors.lastname: Boland
authors.affiliation: Academic Unit of Diabetes and Endocrinology, Royal Hallamshire Hospital, Sheffield, UK.
authors.forename: Jefferson
authors.initials: J
authors.lastname: Marques
authors.affiliation: Academic Unit of Diabetes and Endocrinology, Royal Hallamshire Hospital, Sheffield, UK.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Gandhi
authors.affiliation: Academic Unit of Radiology, The University of Sheffield, Sheffield, UK.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Griffiths
authors.affiliation: Academic Unit of Diabetes and Endocrinology, Royal Hallamshire Hospital, Sheffield, UK.
authors.forename: Solomon
authors.initials: S
authors.lastname: Tesfaye
authors.affiliation: Academic Unit of Radiology, The University of Sheffield, Sheffield, UK.
authors.forename: Iain D
authors.initials: ID
authors.lastname: Wilkinson
mesh_terms: D000328:Adult; D000368:Aged; D017704:Baroreflex; D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D002561:Cerebrovascular Disorders / Q000209:etiology / Q000235:genetics* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000175:diagnosis; D003925:Diabetic Angiopathies / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D018149:Glucose Intolerance / Q000150:complications* / Q000175:diagnosis; D006706:Homeostasis; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011673:Pulsatile Flow
keywords: Type 2 diabetes; cerebrovascular disease; impaired glucose tolerance; magnetic resonance imaging; magnetic resonance phase-contrast angiography; stroke