Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA.
Department of Radiology, Weill Cornell Medicine, New York, New York, USA.
Magn Reson Med. 2018 Mar;79(3):1545-1552. doi: 10.1002/mrm.26808. Epub 2017 Jun 26.
To demonstrate the feasibility of in vivo quantitative susceptibility mapping (QSM) in cardiac MRI and to show that mixed-venous oxygen saturation (SvO ) can be measured non-invasively using QSM.
Electrocardiographic-gated multi-echo 2D gradient echo data were collected at 1.5 T from 14 healthy volunteers during successive breath-holds. Phase wraps and fat chemical shift were removed using a graph-cut-based phase analysis and IDEAL in an iterative approach. The large susceptibility range from air in the lungs to blood in the heart was addressed by using the preconditioning approach in the dipole field inversion. SvO was calculated based on the difference in blood susceptibility between the right ventricle (RV) and left ventricle (LV). Cardiac QSM quality was assessed by two independent readers.
Nine out of fourteen volunteers (64%) yielded interpretable cardiac QSM. QSM maps showed strong differential contrast between RV and LV blood with RV blood having higher susceptibility values (291.5 ± 32.4 ppb), which correspond to 78.3 ± 2.3% SvO .
In vivo cardiac QSM is feasible and can be used to measure SvO , but improvements in data acquisition are needed. Magn Reson Med 79:1545-1552, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
证明心脏 MRI 中体内定量磁化率映射（QSM）的可行性，并表明可以使用 QSM 无创测量混合静脉血氧饱和度（SvO ）。
在 1.5T 下，从 14 名健康志愿者的心电图门控多回波 2D 梯度回波数据中采集数据，在连续的屏气过程中进行采集。使用基于图割的相位分析和 IDEAL 以迭代方式去除相位缠绕和脂肪化学位移。通过在偶极场反演中使用预处理方法，解决了从肺部空气中到心脏血液中的大磁化率范围问题。根据右心室（RV）和左心室（LV）之间血液磁化率的差异，计算 SvO 。由两名独立的读者评估心脏 QSM 的质量。
14 名志愿者中有 9 名（64%）获得了可解释的心脏 QSM。QSM 图谱显示 RV 和 LV 血液之间具有强烈的差异对比，RV 血液具有更高的磁化率值（291.5±32.4 ppb），这对应于 78.3±2.3% SvO 。
体内心脏 QSM 是可行的，可以用于测量 SvO ，但需要改进数据采集。磁共振医学 79：1545-1552，2018。© 2017 国际磁共振医学学会。
