Deutsches Herzzentrum Berlin, Unit of Cardiovascular Imaging, Department of Congenital Heart Disease and Pediatric Cardiology, Berlin, Germany.
J Magn Reson Imaging. 2013 Jan;37(1):208-16. doi: 10.1002/jmri.23793. Epub 2012 Sep 13.
To evaluate the use of four-dimensional (4D) velocity-encoded magnetic resonance imaging (VEC MRI) for blood flow quantification in patients with semilunar valve stenosis and complex accelerated flow.
Peak velocities (Vmax) and stroke volumes (SV) were quantified by 2D and 4D VEC MRI in volunteers (n = 7) and patients with semilunar valve stenosis (n = 18). Measurements were performed above the aortic and pulmonary valve with both techniques and, additionally, at multiple predefined planes in the ascending aorta and in the pulmonary trunk within the 4D dataset. In patients, 4D VEC MRI streamline analysis identified flow patterns and regions of highest flow velocity (4D(max-targeted)) for further measurements and Vmax was also measured by Doppler-echocardiography.
In patients, 4D VEC MRI showed higher Vmax than 2D VEC MRI (2.7 ± 0.6 m/s vs. 2.4 ± 0.5 m/s, P < 0.03) and was more comparable to Doppler-echocardiography (2.8 ± 0.7 m/s). 4D(max-targeted) revealed highest Vmax values (3.1 ± 0.6 m/s). SV measurements showed significant differences between different anatomical levels in the ascending aorta in patients with complex accelerated flow, whereas differences in volunteers with laminar flow patterns were negligible (P = 0.004).
4D VEC MRI improves MRI-derived blood flow quantification in patients with semilunar valve stenosis and complex accelerated flow.
评估四维（4D）速度编码磁共振成像（VEC MRI）在半月瓣狭窄伴复杂加速血流患者中的血流定量应用。
通过二维（2D）和四维（4D）VEC MRI 在志愿者（n=7）和半月瓣狭窄患者（n=18）中定量测量峰值速度（Vmax）和每搏量（SV）。两种技术均在主动脉瓣和肺动脉瓣上方进行测量，并在 4D 数据集的升主动脉和肺动脉干内的多个预设平面上进行额外测量。在患者中，4D VEC MRI 流线分析确定了血流模式和最高流速区域（4D(max-targeted)），以便进一步进行测量，同时还通过多普勒超声心动图测量 Vmax。
在患者中，4D VEC MRI 显示的 Vmax 高于 2D VEC MRI（2.7±0.6 m/s 比 2.4±0.5 m/s，P＜0.03），与多普勒超声心动图更具可比性（2.8±0.7 m/s）。4D(max-targeted) 显示的最大流速值最高（3.1±0.6 m/s）。在复杂加速血流患者的升主动脉不同解剖水平，SV 测量值存在显著差异，而在层流模式的志愿者中，差异可以忽略不计（P=0.004）。
4D VEC MRI 可提高半月瓣狭窄伴复杂加速血流患者的 MRI 血流定量。
