Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S, Kingshighway Blvd, St, Louis, MO 63110, USA.
J Cardiovasc Magn Reson. 2010 Jun 2;12(1):34. doi: 10.1186/1532-429X-12-34.
To assess the feasibility of our newly developed cardiovascular magnetic resonance (CMR) methods to quantify global and/or regional myocardial oxygen consumption rate (MVO2) at rest and during pharmacologically-induced vasodilation in normal volunteers.
A breath-hold T2 quantification method is developed to calculate oxygen extraction fraction (OEF) and MVO2 rate at rest and/or during hyperemia, using a two-compartment model. A previously reported T2 quantification method using turbo-spin-echo sequence was also applied for comparison. CMR scans were performed in 6 normal volunteers. Each imaging session consisted of imaging at rest and during adenosine-induced vasodilation. The new T2 quantification method was applied to calculate T2 in the coronary sinus (CS), as well as in myocardial tissue. Resting CS OEF, representing resting global myocardial OEF, and myocardial OEF during adenosine vasodilation were then calculated by the model. Myocardial blood flow (MBF) was also obtained to calculate MVO2, by using a first-pass perfusion imaging approach.
The T2 quantification method yielded a hyperemic OEF of 0.37 +/- 0.05 and a hyperemic MVO2 of 9.2 +/- 2.4 micromol/g/min. The corresponding resting values were 0.73 +/- 0.05 and 5.2 +/- 1.7 micromol/g/min respectively, which agreed well with published literature values. The MVO2 rose proportionally with rate-pressure product from the rest condition. The T2 sensitivity is approximately 95% higher with the new T2 method than turbo-spin-echo method.
The CMR oxygenation method demonstrates the potential for non-invasive estimation of myocardial oxygenation, and should be explored in patients with altered myocardial oxygenation.
评估我们新开发的心血管磁共振（CMR）方法在正常志愿者中测量静息和药物诱导的血管扩张期间的整体和/或局部心肌耗氧量（MVO2）的可行性。
采用双室模型，开发了一种基于屏气 T2 定量方法来计算静息和/或充血时的氧摄取分数（OEF）和 MVO2 率。还应用了以前报道的使用涡轮自旋回波序列的 T2 定量方法进行比较。在 6 名正常志愿者中进行了 CMR 扫描。每个成像会话包括在静息和腺苷诱导的血管扩张期间进行成像。新的 T2 定量方法应用于计算冠状窦（CS）中的 T2 以及心肌组织中的 T2。然后通过模型计算静息 CS OEF，代表静息时的整体心肌 OEF，以及腺苷血管扩张时的心肌 OEF。还通过首过灌注成像方法获得心肌血流量（MBF）来计算 MVO2。
T2 定量方法得出的充血 OEF 为 0.37 +/- 0.05，充血 MVO2 为 9.2 +/- 2.4 umol/g/min。相应的静息值分别为 0.73 +/- 0.05 和 5.2 +/- 1.7 umol/g/min，与已发表的文献值吻合良好。MVO2 与静息状态下的心率-血压乘积成比例增加。新的 T2 方法的 T2 灵敏度比涡轮自旋回波方法高约 95％。
CMR 氧合方法具有非侵入性估计心肌氧合的潜力，应该在氧合改变的患者中进行探索。
