PURPOSE: To quantify the amplitude and temporal aspects of the blood oxygenation level-dependent (BOLD) response to an auditory stimulus during normocapnia and hypercapnia in healthy subjects in order to establish which BOLD parameters are best suited to infer the cerebrovascular reactivity (CVR) in the middle cerebral artery (MCA) territory. MATERIALS AND METHODS: Twenty healthy volunteers (mean age: 23.6 ± 3.7 years, 11 women) were subjected to a functional paradigm composed of five epochs of auditory stimulus (3 sec) intercalated by six intervals of rest (21 sec). Two levels of hypercapnia were achieved by a combination of air and CO2 while the end-tidal CO2 (ETCO2 ) was continually measured. An autoregressive method was applied to analyze four parameters of the BOLD signal: onset-time, time-to-peak, full-width-at-half-maximum (FWHM), and amplitude. RESULTS: BOLD onset time (P < 0.001) and full-width at half-maximum (FWHM) (P < 0.05) increased linearly, while BOLD amplitude decreased (P < 0.001) linearly with increasing levels of hypercapnia. Test-retest for reproducibility in five subjects revealed excellent concordance for onset time and amplitude. CONCLUSION: The robust linear dependence of BOLD onset time, FWHM, and amplitude to hypercapnia suggest future application of this protocol in clinical studies aimed at evaluating CVR of the MCA territory.
PURPOSE: To quantify the amplitude and temporal aspects of the blood oxygenation level-dependent (BOLD) response to an auditory stimulus during normocapnia and hypercapnia in healthy subjects in order to establish which BOLD parameters are best suited to infer the cerebrovascular reactivity (CVR) in the middle cerebral artery (MCA) territory. MATERIALS AND METHODS: Twenty healthy volunteers (mean age: 23.6 ± 3.7 years, 11 women) were subjected to a functional paradigm composed of five epochs of auditory stimulus (3 sec) intercalated by six intervals of rest (21 sec). Two levels of hypercapnia were achieved by a combination of air and CO2 while the end-tidal CO2 (ETCO2 ) was continually measured. An autoregressive method was applied to analyze four parameters of the BOLD signal: onset-time, time-to-peak, full-width-at-half-maximum (FWHM), and amplitude. RESULTS: BOLD onset time (P < 0.001) and full-width at half-maximum (FWHM) (P < 0.05) increased linearly, while BOLD amplitude decreased (P < 0.001) linearly with increasing levels of hypercapnia. Test-retest for reproducibility in five subjects revealed excellent concordance for onset time and amplitude. CONCLUSION: The robust linear dependence of BOLD onset time, FWHM, and amplitude to hypercapnia suggest future application of this protocol in clinical studies aimed at evaluating CVR of the MCA territory.
Authors: F A Sorond; A Galica; J M Serrador; D K Kiely; I Iloputaife; L A Cupples; L A Lipsitz Journal: Neurology Date: 2010-05-18 Impact factor: 9.910
Authors: Katia C Andrade; Octavio M Pontes-Neto; Joao P Leite; Antonio Carlos Santos; Oswaldo Baffa; Draulio B de Araujo Journal: Arq Neuropsiquiatr Date: 2006-12 Impact factor: 1.420
Authors: Kelley C Mazzetto-Betti; Renata F Leoni; Octavio M Pontes-Neto; Antonio C Santos; Joao P Leite; Afonso C Silva; Draulio B de Araujo Journal: Stroke Date: 2010-08-12 Impact factor: 7.914
Authors: D M Mandell; J S Han; J Poublanc; A P Crawley; J Fierstra; M Tymianski; J A Fisher; D J Mikulis Journal: AJNR Am J Neuroradiol Date: 2011-03-24 Impact factor: 3.825