title: Perfusion reduction in the absence of structural differences in cognitively impaired versus unimpaired RRMS patients.
abstract: Cognitive impairment affects 40%-68% of relapsing-remitting multiple sclerosis (RRMS) patients. Gray matter (GM) demyelination is complicit in cognitive impairment, yet cortical lesions are challenging to image clinically. We wanted to determine whether cortical cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) differences exist between cognitively impaired (CI) and unimpaired (NI) RRMS.
  
  
  
  Prospective study of healthy controls (n = 19), CI (n = 20), and NI (n = 19) undergoing magnetic resonance imaging (MRI) and cognitive testing <1 week apart. White matter (WM) T2 hyperintense lesions and T1 black holes were traced. General linear regression assessed the relationship between lobar WM volume and cortical and WM CBF, CBV, and MTT. Relationship between global and lobar cortical CBF, CBV, and MTT and cognitive impairment was tested using a generalized linear model. Adjusted Bonferroni p < 0.005 was considered significant.
  
  
  
  No significant differences for age, gender, disease duration, and any fractional brain or lesion volume were demonstrated for RRMS subgroups. Expanded Disability Status Scale (EDSS) and Hospital Anxiety and Depression Scale-Depression (HADS-D) were higher in CI. Lobar cortical CBF and CBV were associated with cognitive impairment (p < 0.0001) after controlling for confounders. Cortical CBV accounted for 7.2% of cognitive impairment increasing to 8.7% with cortical CBF (p = 0.06), while WM and cortical CBF accounted for 8.2% of variance (p = 0.04).
  
  
  
  Significant cortical CBF and CBV reduction was present in CI compared to NI in the absence of structural differences.
authors: Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada Parsa.Hojjat@sunnybrook.ca.|University of Toronto, Toronto, ON, Canada Parsa.Hojjat@sunnybrook.ca.
authors: Seyed-Parsa
authors: SP
authors: Hojjat
authors: Department of Biomedical Engineering, Northwestern University, Chicago, IL, USA.
authors: Charles Grady
authors: CG
authors: Cantrell
authors: Department of Radiology, Northwestern University, Chicago, IL, USA.|Department of Biomedical Engineering, Northwestern University, Chicago, IL, USA.|Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
authors: Timothy J
authors: TJ
authors: Carroll
authors: Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
authors: Rita
authors: R
authors: Vitorino
authors: Department of Psychiatry, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.|University of Toronto, Toronto, ON, Canada.
authors: Anthony
authors: A
authors: Feinstein
authors: Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
authors: Lying
authors: L
authors: Zhang
authors: Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.|University of Toronto, Toronto, ON, Canada.
authors: Sean P
authors: SP
authors: Symons
authors: Department of Clinical Neurological Sciences, Western University, London, ON, Canada.
authors: Sarah A
authors: SA
authors: Morrow
authors: Department of Neurology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.|University of Toronto, Toronto, ON, Canada.
authors: Liesly
authors: L
authors: Lee
authors: Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.|University of Toronto, Toronto, ON, Canada.
authors: Paul
authors: P
authors: O'Connor
authors: Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.|University of Toronto, Toronto, ON, Canada.
authors: Richard I
authors: RI
authors: Aviv
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging* / Q000209:etiology; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000150:complications / Q000000981:diagnostic imaging*; D066127:White Matter / Q000000981:diagnostic imaging
keywords: MRI; Multiple sclerosis; demyelination; quantitative MRI; relapsing/remitting