Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri 63110, USA.
J Magn Reson Imaging. 2011 Feb;33(2):320-7. doi: 10.1002/jmri.22322.
To validate a new T(2) -prepared method for the quantification of regional myocardial O(2) consumption during pharmacologic stress with positron emission tomography (PET).
A T(2) prepared gradient-echo sequence was modified to measure myocardial T(2) within a single breath-hold. Six beagle dogs were randomly selected for the induction of coronary artery stenosis. Magnetic resonance imaging (MRI) experiments were performed with the T(2) imaging and first-pass perfusion imaging at rest and during either dobutamine- or dipyridamole-induced hyperemia. Myocardial blood flow (MBF) was quantified using a previously developed model-free algorithm. Hyperemic myocardial O(2) extraction fraction (OEF) and consumption (MVO(2) ) were calculated using a two-compartment model developed previously. PET imaging using (11) C-acetate and (15) O-water was performed in the same day to validate OEF, MBF, and MVO(2) measurements.
The T(2) -prepared mapping sequence measured regional myocardial T(2) with a repeatability of 2.3%. By myocardial segment-basis analysis, MBF measured by MRI is closely correlated with that measured by PET (R(2) = 0.85, n = 22). Similar correlation coefficients were observed for hyperemic OEF (R(2) = 0.90, n = 9, mean difference of PET - MRI = -2.4%) and MVO(2) (R(2) = 0.83, n = 7, mean difference = 4.2%).
The T(2) -prepared imaging method may allow quantitative estimation of regional myocardial oxygenation with relatively good accuracy. The precision of the method remains to be improved.
验证一种新的 T(2) -准备方法，用于通过正电子发射断层扫描（PET）量化药物应激下局部心肌 O(2) 消耗。
修改了 T(2) 准备的梯度回波序列，以便在单次呼吸暂停内测量心肌 T(2)。随机选择六只比格犬诱导冠状动脉狭窄。在静息和多巴酚丁胺或双嘧达莫诱导的充血期间，进行 T(2) 成像和首过灌注成像的磁共振成像（MRI）实验。使用以前开发的无模型算法定量测量心肌血流（MBF）。使用以前开发的两室模型计算充血性心肌 O(2) 提取分数（OEF）和消耗（MVO(2)）。在同一天使用 (11) C-乙酸盐和 (15) O-水进行 PET 成像，以验证 OEF、MBF 和 MVO(2) 的测量值。
T(2) 准备的映射序列以 2.3%的重复性测量局部心肌 T(2)。基于心肌节段的分析，MRI 测量的 MBF 与 PET 测量的 MBF密切相关（R(2) = 0.85，n = 22）。充血性 OEF（R(2) = 0.90，n = 9，PET-MRI 平均差异 = -2.4%）和 MVO(2)（R(2) = 0.83，n = 7，平均差异 = 4.2%）也观察到类似的相关系数。
T(2) 准备的成像方法可能允许对局部心肌氧合进行相对准确的定量估计。该方法的精度仍有待提高。
