title: Examining the regional and cerebral depth-dependent BOLD cerebrovascular reactivity response at 7T.
abstract: Changes in cerebral blood flow (CBF) in response to hypercapnia induced changes in vascular tone, known as cerebrovascular reactivity (CVR), can be measured using the Blood Oxygenation Level Dependent (BOLD) MR contrast. We examine regional differences in the BOLD-CVR response to a progressively increasing hypercapnic stimulus as well as regional BOLD characteristics for the return to baseline normocapnia. CVR across 9 subjects was highest in the cerebral lobes and deep gray matter. Peak CVR in these regions was measured at 3.6±1.6mmHg above baseline end-tidal CO2. White matter CVR was generally reduced compared to that of the gray matter (peak white matter CVR was ~48% lower). A positive relationship between the end-tidal CO2 value at which peak CVR was measured and white matter depth is observed. Furthermore, the time required for the BOLD signal to return to baseline after cessation of the hypercapnic stimulus, was also related to white matter depth; the return, expressed as a time constant, was ~25% longer in white matter. To explain the observed differences in regional CVR response, a model is proposed that takes into account the local architecture of the cerebrovascular, which can result in changes in regional blood flow distribution as a function of end-tidal CO2.
authors: Department of Radiology, University Medical Center Utrecht UMC, H.P. E 01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. Electronic address: A.Bhogal@umcutrecht.nl.
authors: Alex A
authors: AA
authors: Bhogal
authors: Department of Radiotherapy, University Medical Center Utrecht UMC, H.P. E 01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. Electronic address: M.Philippens@umcutrecht.nl.
authors: Marielle E P
authors: ME
authors: Philippens
authors: Department of Radiology, University Medical Center Utrecht UMC, H.P. E 01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. Electronic address: J.C.W.Siero@umcutrecht.nl.
authors: Jeroen C W
authors: JC
authors: Siero
authors: Department of Anesthesia and Pain Management, Toronto General Hospital, 7EN 242, 200 Elizabeth St., Toronto, ON M5G 2C4, Canada. Electronic address: joe.fisher@utoronto.ca.
authors: Joseph A
authors: JA
authors: Fisher
authors: Department of Radiology, University Medical Center Utrecht UMC, H.P. E 01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
authors: Esben Thade
authors: ET
authors: Petersen
authors: Department of Radiology, University Medical Center Utrecht UMC, H.P. E 01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. Electronic address: P.Luijten@umcutrecht.nl.
authors: Peter R
authors: PR
authors: Luijten
authors: Department of Radiology, University Medical Center Utrecht UMC, H.P. E 01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. Electronic address: J.M.Hoogduin-2@umcutrecht.nl.
authors: Hans
authors: H
authors: Hoogduin
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000187:drug effects / Q000503:physiopathology*; D001931:Brain Mapping; D002245:Carbon Dioxide / Q000008:administration & dosage; D002560:Cerebrovascular Circulation / Q000187:drug effects; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D066127:White Matter / Q000098:blood supply / Q000187:drug effects / Q000503:physiopathology
chemical_list: D002245:Carbon Dioxide
keywords: 7T; BOLD; CVR; Hypercapnia; Regional cerebrovascular reactivity; White matter