A generalized procedure for calibrated MRI incorporating hyperoxia and hypercapnia
A generalized procedure for calibrated MRI incorporating hyperoxia and hypercapnia
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DOI：
10.1002/hbm.21495
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发表时间：
2013-05-01
影响因子：
4.8
通讯作者：
Hoge, Richard D.
中科院分区：
文献类型：
--
作者：
Gauthier, Claudine J.;Hoge, Richard D.
校准的MRI技术使用由呼吸操作诱发的脑血流量（CBF）和血氧水平依赖性（BOLD）信号的变化来外推归因于静息时脱氧血红蛋白（M）的总BOLD信号。然后，该参数可以用于基于任务诱导的BOLD和CBF信号来估计脑氧消耗代谢率（CMRO 2）的变化。之前已经描述了不同的方法，包括增加吸入CO2（高碳酸血症）或补充O2（高氧）。我们在这里提出了一个广义的BOLD信号模型，在适当的条件下减少到以前的模型单独高碳酸血症或高氧，并适用于混合呼吸操作，包括同时高碳酸血症和高氧。这种新的方法产生强大的和准确的M地图，从而允许更可靠的估计CMRO 2变化引起的视觉任务。广义模型是有效的任意流量的变化，在高氧，从而受益于更大的总氧合变化所产生的血液中的氧含量增加，从高氧结合高碳酸血症的流量增加。这又降低了估计M所需的外推程度。新程序产生的M估计值（7.6 +/- 2.6）通常高于视觉区通过高碳酸血症（5.6 +/- 1.8）或单纯高氧（4.5 +/- 1.5）获得的M估计值。这些M值及其空间分布代表了对静息时组织脱氧血红蛋白潜在分布的更准确和更稳健的描述，从而更准确地估计诱发的CMRO 2变化。^Brain Mapp，2013. (c)2012 Wiley Periodicals，Inc.
Calibrated MRI techniques use the changes in cerebral blood flow (CBF) and blood oxygenation level-dependent (BOLD) signal evoked by a respiratory manipulation to extrapolate the total BOLD signal attributable to deoxyhemoglobin at rest (M). This parameter can then be used to estimate changes in the cerebral metabolic rate of oxygen consumption (CMRO2) based on task-induced BOLD and CBF signals. Different approaches have been described previously, including addition of inspired CO2 (hypercapnia) or supplemental O2 (hyperoxia). We present here a generalized BOLD signal model that reduces under appropriate conditions to previous models derived for hypercapnia or hyperoxia alone, and is suitable for use during hybrid breathing manipulations including simultaneous hypercapnia and hyperoxia. This new approach yields robust and accurate M maps, in turn allowing more reliable estimation of CMRO2 changes evoked during a visual task. The generalized model is valid for arbitrary flow changes during hyperoxia, thus benefiting from the larger total oxygenation changes produced by increased blood O2 content from hyperoxia combined with increases in flow from hypercapnia. This in turn reduces the degree of extrapolation required to estimate M. The new procedure yielded M estimates that were generally higher (7.6 +/- 2.6) than those obtained through hypercapnia (5.6 +/- 1.8) or hyperoxia alone (4.5 +/- 1.5) in visual areas. These M values and their spatial distribution represent a more accurate and robust depiction of the underlying distribution of tissue deoxyhemoglobin at rest, resulting in more accurate estimates of evoked CMRO2 changes. Hum Brain Mapp, 2013. (c) 2012 Wiley Periodicals, Inc.