Cortical oxygen extraction fraction using quantitative BOLD MRI and cerebral blood flow during vasodilation.
Cortical oxygen extraction fraction using quantitative BOLD MRI and cerebral blood flow during vasodilation.
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DOI：
10.3389/fphys.2023.1231793
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发表时间：
2023
影响因子：
4
通讯作者：
中科院分区：
文献类型：
--
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前言：我们的目标是通过定量BOLD MRI模型在基线和药物血管扩张后对局部氧摄取分数(OEF)进行非侵入性测量。我们假设，在健康条件下，乙酰唑胺(ACZ)的血管扩张反应导致OEF降低，反映了脑血流量(CBF)增加的区域的代偿，而脑氧代谢率(CMRO2)保持不变。我们还旨在评估OEF和默认模式网络(DMN)区域的血流灌注的关系，默认模式网络(DMN)区域已显示出与不同神经条件下的血管危险因素和脑血管反应性相关。材料和方法：8例健康受试者(年龄47±13岁，女性6例)，在3T扫描仪上用32通道磁头线圈分别在给药前和给药后进行扫描。磁共振成像采集方案包括：1)梯度回声层激发剖面成像不对称自旋回波扫描定量OEF、去氧血容量和可逆横向松驰率(R2‘)；2)多后标记延迟动脉自旋标记扫描测量CBF。为了评估由于血管扩张引起的每个参数的变化，对DMN脑区的所有对(基线和血管扩张)进行了双向t检验，并进行了多次比较。使用线性混合效应模型分析和比较了不同DMN地区CBF与OEF和CBF与R2‘的关系。结果：血管扩张时，额叶内侧皮质()、扣带回后部(PCG)、楔前叶皮质(PCun)和枕极(PCUN)的CBF显著增加。同时，OEF仅在PCG(8.8%)和PCUN()观察到显著下降。CMRO2在血管扩张后有升高的趋势，但经多次比较校正后差异不显著，虽然R2‘有轻微下降的趋势，但对ACZ的反应在任何区域均未发现统计学意义的变化。ACZ对CBF的反应与OEF(；)呈较强的负相关，与R2‘(；)呈显著负相关。结论：定量BOLD模型可以可靠地测量多种生理条件下的OEF，并以比R2值更高的灵敏度捕捉血管的变化。DMN中不同区域的OEF和CBF之间的负相关性表明，这两项测量对ACZ血管扩张的反应，是这一健康队列中组织健康状况的可靠指标。
Introduction: We aimed to demonstrate non-invasive measurements of regional oxygen extraction fraction (OEF) from quantitative BOLD MRI modeling at baseline and after pharmacological vasodilation. We hypothesized that OEF decreases in response to vasodilation with acetazolamide (ACZ) in healthy conditions, reflecting compensation in regions with increased cerebral blood flow (CBF), while cerebral metabolic rate of oxygen (CMRO2) remained unchanged. We also aimed to assess the relationship between OEF and perfusion in the default mode network (DMN) regions that have shown associations with vascular risk factors and cerebrovascular reactivity in different neurological conditions. Material and methods: Eight healthy subjects (47 ± 13 years, 6 female) were scanned on a 3 T scanner with a 32-channel head coil before and after administration of 15 mg/kg ACZ as a pharmacological vasodilator. The MR imaging acquisition protocols included: 1) A Gradient Echo Slice Excitation Profile Imaging Asymmetric Spin Echo scan to quantify OEF, deoxygenated blood volume, and reversible transverse relaxation rate (R2 ’) and 2) a multi-post labeling delay arterial spin labeling scan to measure CBF. To assess changes in each parameter due to vasodilation, two-way t-tests were performed for all pairs (baseline versus vasodilation) in the DMN brain regions with Bonferroni correction for multiple comparisons. The relationships between CBF versus OEF and CBF versus R2’ were analyzed and compared across DMN regions using linear, mixed-effect models. Results: During vasodilation, CBF significantly increased in the medial frontal cortex (), posterior cingulate gyrus (pCG) (), precuneus cortex (PCun) (), and occipital pole (). Concurrently, a significant decrease in OEF was observed only in the pCG (8.8%, ) and PCun (). CMRO2 showed a trend of increased values after vasodilation, but these differences were not significant after correction for multiple comparisons Although R2’ showed a slightly decreasing trend, no statistically significant changes were found in any regions in response to ACZ. The CBF response to ACZ exhibited a stronger negative correlation with OEF (; ), than with R2’ (; ). Conclusion: Quantitative BOLD modeling can reliably measure OEF across multiple physiological conditions and captures vascular changes with higher sensitivity than R2’ values. The inverse correlation between OEF and CBF across regions in DMN, suggests that these two measurements, in response to ACZ vasodilation, are reliable indicators of tissue health in this healthy cohort.
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影响因子：
9.3
作者：
Cleland NRW;Al-Juboori SI;Dobrinskikh E;Bruce KD
通讯作者：
Bruce KD
DOI：
10.1073/pnas.1801582115
发表时间：
2018-07-03
影响因子：
11.1
作者：
Coalson, Timothy S.;Van Essen, David C.;Glasser, Matthew F.
通讯作者：
Glasser, Matthew F.
影响因子：
5.7
作者：
Groves, Adrian R.;Chappell, Michael A.;Woolrich, Mark W.
通讯作者：
Woolrich, Mark W.
影响因子：
17.7
作者：
Frazier, JA;Chiu, SF;Biederman, J
通讯作者：
Biederman, J
影响因子：
5.7
作者：
Fonov V;Evans AC;Botteron K;Almli CR;McKinstry RC;Collins DL;Brain Development Cooperative Group
通讯作者：
Brain Development Cooperative Group