title: CO2 blood oxygen level-dependent MR mapping of cerebrovascular reserve in a clinical population: safety, tolerability, and technical feasibility.
abstract: OBJECTIVE
  To evaluate the safety, tolerability, and technical feasibility of mapping cerebrovascular reactivity (CVR) in a clinical population by using a precise prospectively targeted CO(2) stimulus and blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging.
  
  
  METHODS
  A chart review was performed of all CVR studies from institutional review board-approved projects at a tertiary care hospital between January 1, 2006, and December 1, 2010. Informed consent was obtained. Records were searched for the incidence of adverse events and failed examinations. CVR maps were evaluated for diagnostic quality by two blinded observers and were categorized as good, diagnostic but suboptimal, or nondiagnostic. Outcomes were presented as raw data and descriptive statistics (means ± standard deviations). Intraclass correlation coefficient was used to determine interobserver variability.
  
  
  RESULTS
  Four hundred thirty-four consecutive CVR examinations from 294 patients (51.8% female patients) were studied. Patient age ranged from 9 to 88 years (mean age, 45.9 years ± 20.6). Transient symptoms, such as shortness of breath, headache, and dizziness, were reported in 48 subjects (11.1% of studies) during hypercapnic phases only. There were no neurologic ischemic events, myocardial infarctions, or other major complications. The success rate in generating CVR maps was 83.9% (364 of 434). Of the 70 (16.1%) failed examinations, 25 (35.7%) were due to discomfort; eight (11.4%), to head motion; two (2.9%), to inability to cooperate; seven (10.0%), to technical difficulties with equipment; and 28 (40.0%), to unknown or unspecified conditions. Among the 364 remaining successful examinations, good quality CVR maps were obtained in 340 (93.4%); diagnostic but suboptimal, in 12 (3.3%); and nondiagnostic, in 12 (3.3%).
  
  
  CONCLUSIONS
  CVR mapping by using a prospectively targeted CO(2) stimulus and BOLD MR imaging is safe, well tolerated, and technically feasible in a clinical patient population.
authors.affiliation: Joint Department of Medical Imaging, Division of Neuroradiology, University Health Network, University of Toronto, 399 Bathurst St, 3MC-431, Toronto, ON, Canada M5T 2S8.
authors.forename: Vincent R
authors.initials: VR
authors.lastname: Spano
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Mandell
authors.forename: Julien
authors.initials: J
authors.lastname: Poublanc
authors.forename: Kevin
authors.initials: K
authors.lastname: Sam
authors.forename: Anne
authors.initials: A
authors.lastname: Battisti-Charbonney
authors.forename: Olivia
authors.initials: O
authors.lastname: Pucci
authors.forename: Jay S
authors.initials: JS
authors.lastname: Han
authors.forename: Adrian P
authors.initials: AP
authors.lastname: Crawley
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Fisher
authors.forename: David J
authors.initials: DJ
authors.lastname: Mikulis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002245:Carbon Dioxide / Q000097:blood*; D002560:Cerebrovascular Circulation; D002648:Child; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010100:Oxygen / Q000097:blood*; D012189:Retrospective Studies
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen