Department of Cardiovascular Medicine, University of Oxford, Centre for Clinical Magnetic Resonance Research, Oxford, UK.
NMR Biomed. 2012 Jan;25(1):27-34. doi: 10.1002/nbm.1708. Epub 2011 Jul 19.
We report the first comparison of cardiovascular magnetic resonance imaging (CMR) at 1.5 T, 3 T and 7 T field strengths using steady state free precession (SSFP) and fast low angle shot (FLASH) cine sequences. Cardiac volumes and mass measurements were assessed for feasibility, reproducibility and validity at each given field strength using FLASH and SSFP sequences. Ten healthy volunteers underwent retrospectively electrocardiogram (ECG) gated CMR at 1.5 T, 3 T and 7 T using FLASH and SSFP sequences. B1 and B0 shimming and frequency scouts were used to optimise image quality. Cardiac volume and mass measurements were not significantly affected by field strength when using the same imaging sequence (P > 0.05 for all parameters at 1.5 T, 3 T and 7 T). SSFP imaging returned larger end diastolic and end systolic volumes and smaller left ventricular masses than FLASH imaging at 7 T, and at the lower field strengths (P < 0.05 for each parameter). However, univariate general linear model analysis with fixed effects for sequence and field strengths found an interaction between imaging sequence and field strength (P = 0.03), with a smaller difference in volumes and mass measurements between SSFP and FLASH imaging at 7 T than 1.5 T and 3 T. SSFP and FLASH cine imaging at 7 T is technically feasible and provides valid assessment of cardiac volumes and mass compared with CMR imaging at 1.5 T and 3 T field strengths.
我们报告了使用稳态自由进动（SSFP）和快速小角度激发（FLASH）电影序列在 1.5 T、3 T 和 7 T 场强下进行心血管磁共振成像（CMR）的首次比较。使用 FLASH 和 SSFP 序列评估了每个特定场强下的心脏容积和质量测量的可行性、可重复性和有效性。10 名健康志愿者使用 FLASH 和 SSFP 序列在 1.5 T、3 T 和 7 T 进行回顾性心电图（ECG）门控 CMR。使用 B1 和 B0 匀场和频率 scouts 来优化图像质量。当使用相同的成像序列时，心脏容积和质量测量不受场强的影响（在 1.5 T、3 T 和 7 T 时所有参数的 P > 0.05）。在 7 T 时，SSFP 成像返回的舒张末期和收缩末期容积大于 FLASH 成像，在较低的场强下（每个参数的 P < 0.05）。然而，使用序列和场强的固定效应进行单变量一般线性模型分析发现成像序列和场强之间存在相互作用（P = 0.03），在 7 T 时 SSFP 和 FLASH 成像之间的容积和质量测量差异小于 1.5 T 和 3 T。7 T 时的 SSFP 和 FLASH 电影成像在技术上是可行的，与 1.5 T 和 3 T 场强的 CMR 成像相比，可提供心脏容积和质量的有效评估。
