Kupari M, Järvinen V, Poutanen V P, Hekali P
First Department of Medicine, Helsinki University Central Hospital, Finland.
Am J Physiol. 1995 Mar;268(3 Pt 2):H1232-8. doi: 10.1152/ajpheart.1995.268.3.H1232.
The spatial distribution of instantaneous diastolic flow velocities across the mitral annulus was studied with cardiac gated cine magnetic resonance imaging in 10 healthy persons aged 26-46 yr. Velocity encoding used two interleaved gradient echo pulse sequences with velocity sensitivity in the direction of flow perpendicular to the annular imaging plane. Velocity maps were reconstructed at 30- to 43-ms intervals throughout diastole. Velocity-time curves and mean flow rates were determined in five regions of the mitral annulus using a 0.6-cm2 measurement area. The spatial velocity minimum was consistently in the anterolateral commissural area, whereas the maximum was in the anterior annulus in early diastole shifting posteromedially in late diastole. The mean flow rate (+/- SD) averaged 18.4 +/- 8.1 ml.s-1.cm-2 of annular area centrally, 18.3 +/- 7.2 ml.s-1.cm-2 anteriorly, 16.9 +/- 7.4 ml.s-1.cm-2 posteriorly, 13.0 +/- 7.7 ml.s-1.cm-2 in the anterolateral commissural area, and 23.0 +/- 7.3 ml.s-1.cm-2 in the posteromedial commissural area (P < 0.001). We conclude that mitral transannular flow shows marked spatial inhomogeneity in normal humans. The skewness of flow profiles compromises the use of local velocity measurements as indexes of left ventricular filling.
采用心脏门控电影磁共振成像技术，对10名年龄在26 - 46岁的健康人二尖瓣环上瞬时舒张期血流速度的空间分布进行了研究。速度编码采用两个交错的梯度回波脉冲序列，其速度灵敏度方向垂直于瓣环成像平面的血流方向。在整个舒张期以30至43毫秒的间隔重建速度图。使用0.6平方厘米的测量区域，在二尖瓣环的五个区域测定速度 - 时间曲线和平均流速。空间速度最小值始终位于前外侧连合处，而最大值在舒张早期位于前瓣环，在舒张晚期向后内侧移位。平均流速（±标准差）在瓣环中心区域平均为18.4±8.1毫升·秒⁻¹·厘米⁻²，前侧为18.3±7.2毫升·秒⁻¹·厘米⁻²，后侧为16.9±7.4毫升·秒⁻¹·厘米⁻²，前外侧连合处为13.0±7.7毫升·秒⁻¹·厘米⁻²，后内侧连合处为23.0±7.3毫升·秒⁻¹·厘米⁻²（P < 0.001）。我们得出结论，在正常人中二尖瓣跨瓣环血流显示出明显的空间不均匀性。血流分布的偏态性影响了将局部速度测量作为左心室充盈指标的应用。
