Effects of Thoracic Pressure Changes on MRI Signals in the Brain. Issue 6 (June 2015)

• Record Type: Journal Article
• Authors: Wu, Paula; Bandettini, Peter A; Harper, Ronald M; Handwerker, Daniel A
• Is Part Of: Journal of cerebral blood flow & metabolism. Volume 35:Issue 6(2015)
• Page Start: 1024
• Page End: 1032
• Publication Date: 2015-06
• Subjects: breath hold -- cerebral blood flow -- functional MRI -- hypercapnia -- Valsalva; Cerebral circulation -- Periodicals; Brain -- Metabolism -- Periodicals; Brain -- Blood-vessels -- Periodicals; Cerebrovascular disease -- Periodicals; 612.824
• DOI: 10.1038/jcbfm.2015.20
• Languages: English
• ISSNs: 0271-678X

Abstract

Cerebrovascular stressors, such as breath holding or CO2 inhalation, cause global magnetic resonance imaging (MRI) signal changes. In this study, we show that intrathoracic pressure changes cause rapid MRI signal alterations that have similar spatial patterns to the changes associated with breath holding or CO2 inhalation. Nine subjects performed the Valsalva maneuver during functional MRI data collection. Expiratory pressures ranged from 10 to 40 mm Hg. Breath holds ending on either inhalation or exhalation were also collected. The maximal and minimal functional MRI (fMRI) signal scaled with thoracic pressure load, and the overall amplitude of responses to the Valsalva varied, depending on brain tissue. Additionally, a Valsalva effort as short as 5 seconds yielded signal changes similar in spatial distribution and magnitude to a 20-second breath hold, suggesting potential applications of the Valsalva maneuver for calibrated fMRI experiments.