Department of Cardiovascular Medicine, Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom.
Circ Cardiovasc Imaging. 2010 Jan;3(1):32-40. doi: 10.1161/CIRCIMAGING.109.860148. Epub 2009 Nov 17.
It is recognized that the interplay between myocardial ischemia, perfusion, and oxygenation in the setting of coronary artery disease (CAD) is complex and that myocardial oxygenation and perfusion may become dissociated. Blood oxygen level-dependent (BOLD) cardiovascular magnetic resonance (CMR) has the potential to noninvasively measure myocardial oxygenation, whereas positron emission tomography (PET) with oxygen-15 labeled water is the gold standard technique for myocardial blood flow quantification. Thus, we sought to apply BOLD CMR at 3 T and oxygen-15-labeled water PET in patients with CAD and normal volunteers to better understand the relationship between regional myocardial oxygenation and blood flow during vasodilator stress.
Twenty-two patients (age, 62+/-8 years; 16 men) with CAD (at least 1 stenosis > or =50% on quantitative coronary angiography) and 10 normal volunteers (age, 58+/-6 years; 6 men) underwent 3-T BOLD CMR and PET. For BOLD CMR, 4 to 6 midventricular short-axis images were acquired at rest and during adenosine stress (140 microg/kg/min). Using PET with oxygen-15-labeled water, myocardial blood flow was measured at baseline and during adenosine in the same slices. BOLD images were divided into 6 segments, and mean signal intensities calculated. Taking > or =50% stenosis on quantitative coronary angiography as the gold standard, cutoff values for stress myocardial blood flow (<2.45 mL/min/g; AUC, 0.83) and BOLD signal intensity change (<3.74%; AUC, 0.78) were determined to define ischemic segments. BOLD CMR and PET agreed on the presence or absence of ischemia in 18 of the 22 patients (82%) and in all normal subjects. On a per-segment analysis, 40% of myocardial segments with stress myocardial blood flow below the cutoff of 2.45 mL/min/g did not show deoxygenation, whereas 88% of segments with normal perfusion also had normal oxygenation measurements.
Regional myocardial perfusion and oxygenation may be dissociated, indicating that in patients with CAD, reduced perfusion does not always lead to deoxygenation.
在冠心病（CAD）患者中，心肌缺血、灌注和氧合之间的相互作用是复杂的，并且心肌氧合和灌注可能会分离。血氧水平依赖（BOLD）心血管磁共振（CMR）具有无创性测量心肌氧合的潜力，而氧-15 标记水的正电子发射断层扫描（PET）是心肌血流量定量的金标准技术。因此，我们试图在 CAD 患者和正常志愿者中应用 3T 的 BOLD CMR 和氧-15 标记水的 PET，以更好地了解在血管扩张剂应激期间局部心肌氧合与血流之间的关系。
22 例 CAD 患者（年龄 62+/-8 岁；16 名男性）和 10 例正常志愿者（年龄 58+/-6 岁；6 名男性）接受了 3T 的 BOLD CMR 和 PET。对于 BOLD CMR，在休息和腺苷应激（140μg/kg/min）时采集 4 到 6 个中隔短轴图像。使用氧-15 标记水的 PET，在基线和腺苷期间测量相同切片中的心肌血流量。BOLD 图像分为 6 个节段，计算平均信号强度。以定量冠状动脉造影上的 > 或 = 50%狭窄作为金标准，确定应激心肌血流量（<2.45 mL/min/g；AUC，0.83）和 BOLD 信号强度变化（<3.74%；AUC，0.78）的截断值来定义缺血节段。22 例患者中的 18 例（82%）和所有正常受试者的 BOLD CMR 和 PET 在缺血的存在或不存在方面一致。在分段分析中，40%的心肌节段的应激心肌血流低于 2.45 mL/min/g 的截断值，但没有出现去氧，而 88%的正常灌注节段也有正常的氧合测量值。
局部心肌灌注和氧合可能分离，表明在 CAD 患者中，灌注减少并不总是导致去氧。
