Christian Timothy F, Bell Stephen P, Whitesell Lawrence, Jerosch-Herold Michael
University of Vermont College of Medicine, Burlington, Vermont, USA.
JACC Cardiovasc Imaging. 2009 Sep;2(9):1103-10. doi: 10.1016/j.jcmg.2009.06.009.
The aim of this study was to determine the accuracy of cardiac magnetic resonance (CMR) first pass (FP) perfusion measures of absolute myocardial blood flow (MBF) with a 3.0-T magnet and compare these measures with FP perfusion at 1.5-T with absolute MBF by labeled microspheres as the gold standard.
First-pass magnetic resonance (MR) myocardial perfusion imaging can quantify MBF, but images are of low signal at conventional magnetic field strength due to the need for rapid acquisition.
A pig model was used to alter MBF in a coronary artery during FP CMR (intracoronary adenosine followed by ischemia). This produces an active zone with a range of MBF and a control zone. Microspheres were injected into the left atrium with concurrent reference sampling. FP MR perfusion imaging was performed at 1.5-T (n = 9) or 3.0-T (n = 8) with a saturation-recovery gradient echo sequence in short-axis slices during a bolus injection of 0.025 mmol/kg gadolinium-diethylenetriamine pentaacetic acid. Fermi function deconvolution was performed on active and control region of interest from short-axis slices with an arterial input function derived from the left ventricular cavity. These MR values of MBF were matched to microsphere values obtained from short-axis slices at pathology.
Occlusion MBF was 0.21 +/- 0.26 ml/min/g, adenosine MBF was 2.28 +/- 0.99 ml/min/g, and control zone MBF was 0.70 +/- 0.22 ml/min/g. The correlation of MR FP CMR with microsphere was close for both field strengths: 3.0-T, r = 0.98, p < 0.0001 and 1.5-T, r = 0.95, p < 0.0001. The 95% confidence limits of agreement were slightly narrower at 3.0-T (3.0-T = 0.49 ml/min/g, 1.5-T = 0.68 ml/min/g, p < 0.05). The FP CMR image characteristics were better at 3.0-T (noise and contrast enhancement were both superior at 3.0-T). In myocardial zones where MBF <0.50 ml/min/g, the correlation with microspheres was closer at 3.0-T (r = 0.55 at 1.5-T, r = 0.85 at 3.0-T).
Absolute MBF by FP perfusion imaging is accurate at both 1.5- and 3.0-T. Signal quality is better at 3.0-T, which might confer a benefit for estimating MBF in ischemic zones.
本研究旨在确定使用3.0-T磁共振成像仪进行心脏磁共振（CMR）首过（FP）灌注测量绝对心肌血流量（MBF）的准确性，并将这些测量结果与1.5-T时的FP灌注结果进行比较，以标记微球测量的绝对MBF作为金标准。
首过磁共振（MR）心肌灌注成像可定量MBF，但由于需要快速采集，在传统磁场强度下图像信号较低。
采用猪模型在FP CMR期间改变冠状动脉内的MBF（冠状动脉内注射腺苷后再进行缺血处理）。这会产生一个具有一系列MBF的活性区和一个对照区。在左心房注射微球并同时进行参考采样。在1.5-T（n = 9）或3.0-T（n = 8）下，使用饱和恢复梯度回波序列在短轴切片上进行团注0.025 mmol/kg钆-二乙烯三胺五乙酸时的FP MR灌注成像。对短轴切片上的活性和对照感兴趣区域进行费米函数反卷积，动脉输入函数来自左心室腔。将这些MBF的MR值与病理检查时从短轴切片获得的微球值进行匹配。
闭塞时MBF为0.21±0.26 ml/min/g，腺苷时MBF为2.28±0.99 ml/min/g，对照区MBF为0.70±0.22 ml/min/g。两种场强下MR FP CMR与微球的相关性都很密切：3.0-T时，r = 0.98，p < 0.0001；1.5-T时，r = 0.95，p < 0.0001。3.0-T时一致性的95%置信限略窄（3.0-T = 0.49 ml/min/g，1.5-T = 0.68 ml/min/g，p < 0.05）。3.0-T时FP CMR图像特征更好（3.0-T时噪声和对比增强均更优）。在MBF <0.50 ml/min/g的心肌区域，3.0-T时与微球的相关性更密切（1.5-T时r = 0.55，3.0-T时r = 0.85）。
FP灌注成像测量的绝对MBF在1.5-T和3.0-T时均准确。3.0-T时信号质量更好，这可能有助于估计缺血区域的MBF。
