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Increasing mean airway pressure reduces functional MRI (fMRI) signal in the primary visual cortex.

Abstract：

:Changes in both blood flow and blood oxygenation determine the functional MRI (fMRI) signal. In the present study factors responsible for blood oxygenation (e.g., FiO(2)) were held constant so that changes in pixel count would above all reflect changes in regional cerebral blood flow (rCBF). Continuous positive airway pressure (CPAP) breathing at 12 cm H(2)O, which was previously shown to influence rCBF, was applied in human volunteers (n = 19) to investigate the sensitivity of fMRI for changes in rCBF caused by increased mean airway pressure. Increasing the mean airway pressure decreased the pixel count in the primary visual cortex (median (range)): baseline: 219 (58-425) pixels vs. CPAP (12 cm H(2)O): 92 (0-262) pixels). These findings indicate that fMRI is sensitive to detect a reduced rCBF-response in the primary visual cortex. The underlying mechanism is likely to be a reduced basal rCBF due to constriction and/or compression of postcapillary venoles during CPAP breathing. These findings are important for interpreting fMRI results in awake and in artificially respirated patients, in whom positive airway pressure is used to improve pulmonary function during the diagnostic procedure.

journal_name

Magn Reson Imaging

journal_title

Magnetic resonance imaging

authors

Lorenz IH,Kolbitsch C,Hörmann C,Schocke M,Kremser C,Zschiegner F,Felber S,Benzer A

doi

10.1016/s0730-725x(00)00229-0

subject

Has Abstract

pub_date

2001-01-01 00:00:00

pages

7-11

issue

1

eissn

0730-725X

issn

1873-5894

pii

S0730-725X(00)00229-0

journal_volume

19

pub_type

杂志文章

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