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Query: UMLS:C0242706 (
hyperoxia
)
5,219
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Cerebral blood flow (CBF) was measured by the 133Xe inhalation method in patients with multi-infarct dementia (MID, N = 26), Alzheimer's
dementia
(AD, N = 19), and among age-matched, neurologically normal, healthy volunteers (N = 26). Cognitive performance was assessed in all subjects using the Cognitive Capacity Screening Examination (CCSE). Cerebral vasomotor responses were calculated from differences in values of mean hemispheric gray matter blood flow (Delta CBF) measured during inhalation of 100% oxygen (
hyperoxia
) compared with CBF measured while breathing room air. Significant correlations were found between CCSE performance and vasomotor responsiveness in patients with MID (P less than .01), but not in patients with AD or in neurologically normal volunteers. Loss of vasomotor responsiveness is an indicator of cerebrovascular disease with rigidity and/or loss of reactivity of cerebral vessels, which impairs cerebrovascular responses to situational demands and predisposes to cerebral ischemia. Loss of cerebral vasomotor responsiveness among MID patients, which is a biologic marker of cerebrovascular disease, provides confirmatory evidence of the vascular etiology of MID and assists in separating MID from AD patients.
...
PMID:Cognitive performance correlates with cerebrovascular impairments in multi-infarct dementia. 395 10
Calibrated fMRI based on arterial spin-labeling (ASL) and blood oxygen-dependent contrast (BOLD), combined with periods of hypercapnia and
hyperoxia
, can provide information on cerebrovascular reactivity (CVR), resting blood flow (CBF), oxygen extraction fraction (OEF), and resting oxidative metabolism (CMRO
2
). Vascular and metabolic integrity are believed to be affected in Alzheimer's disease (AD), thus, the use of calibrated fMRI in AD may help understand the disease and monitor therapeutic responses in future clinical trials. In the present work, we applied a calibrated fMRI approach referred to as Quantitative O2 (QUO2) in a cohort of probable AD
dementia
and age-matched control participants. The resulting CBF, OEF and CMRO
2
values fell within the range from previous studies using positron emission tomography (PET) with
15
O labeling. Moreover, the typical parietotemporal pattern of hypoperfusion and hypometabolism in AD was observed, especially in the precuneus, a particularly vulnerable region. We detected no deficit in frontal CBF, nor in whole grey matter CVR, which supports the hypothesis that the effects observed were associated specifically with AD rather than generalized vascular disease. Some key pitfalls affecting both ASL and BOLD methods were encountered, such as prolonged arterial transit times (particularly in the occipital lobe), the presence of susceptibility artifacts obscuring medial temporal regions, and the challenges associated with the hypercapnic manipulation in AD patients and elderly participants. The present results are encouraging and demonstrate the promise of calibrated fMRI measurements as potential biomarkers in AD. Although CMRO
2
can be imaged with
15
O PET, the QUO2 method uses more widely available imaging infrastructure, avoids exposure to ionizing radiation, and integrates with other MRI-based measures of brain structure and function.
...
PMID:Application of calibrated fMRI in Alzheimer's disease. 2856 Jan 60
