In:
Journal of Magnetic Resonance Imaging, Wiley, Vol. 13, No. 3 ( 2001-03), p. 344-351
Abstract:
The purpose of this study was to examine which physiological factors affect cerebral T2* signal intensity (SI) during breath holding (BH) (apnea after inspiration and breathing after expiration) in normal volunteers. We examined SI changes caused by anoxic gas inhalation, by respiratory movements, and by BH. High‐speed echo planar images (EPI) showed changes in SI that could be divided into five phases. Reports indicate that SI changes induced by BH are due to the effects on the magnetic susceptibility of deoxygenated hemoglobin (deoxyhemoglobin (dHb)) and to hypercapnia, but these reports could not fully explain the observed five phases. In addition to deoxyhemoglobin susceptibility and hypercapnia, we found that respiratory movements play a third critical role in modifying SI by affecting blood flow into the region of interest (ROI), as judged from right carotid artery flow. Consequently, we propose that the physiological SI changes induced by BH are derived from blood oxygenation, hypercapnia, and respiratory movements. J. Magn. Reson. Imaging 2001;13:344–351. © 2001 Wiley‐Liss, Inc.
Type of Medium:
Online Resource
ISSN:
1053-1807
,
1522-2586
Language:
English
Publisher:
Wiley
Publication Date:
2001
detail.hit.zdb_id:
1497154-9
