Ruesink Timothy, Medero Rafael, Rutkowski David, Roldán-Alzate Alejandro
Department of Mechanical Engineering, University of Wisconsin - Madison, Madison, WI, USA.
Department of Radiology, University of Wisconsin - Madison, Madison, WI, USA.
Cardiovasc Eng Technol. 2018 Dec;9(4):674-687. doi: 10.1007/s13239-018-00377-z. Epub 2018 Sep 14.
Arterial stiffness has predictive value for cardiovascular disease (CVD). Local artery stiffness can provide insight on CVD pathology and may be useful for diagnosis and prognosis. However, current methods are invasive, require real-time expertise for measurement, or are limited by arterial region. 4D Flow MRI can non-invasively measure local stiffness by estimating local pulse wave velocity (PWV). This technique can be applied to vascular regions, previously accessible only by invasive stiffness measurement methods. MRI PWV data can also be analyzed post-exam. However, 4D Flow MRI requires validation before it is used in vivo to measure local PWV.
PWV, calculated from 4D Flow MRI and a benchtop experiment, was compared with petersons elastic modulus (PEM) of in vitro models. PEM was calculated using high-speed camera images and pressure transducers. Three transit-time algorithms were analyzed for PWV measurement accuracy and precision.
PWV from 4D Flow MRI and reference benchtop experiments show strong correlation with PEM (R = 0.99). The cross correlation transit-time algorithm showed the lowest percent difference between 4D Flow MRI and benchtop experiments (4-7%), and the point to point of 50% upstroke algorithm had the highest transit-time vs. distance data average R (0.845).
4D Flow MRI is a feasible method for estimating local PWV in simple in vitro models and is a viable tool for clinical analysis. In addition, choice in transit-time algorithm depends on flow waveform shape and arterial region. This study strengthens the validity of 4D Flow MRI local PWV measurement in simple models. However, this technique requires validation in more complex models before it is used in vivo.
动脉僵硬度对心血管疾病（CVD）具有预测价值。局部动脉僵硬度可为CVD病理学提供见解，可能有助于诊断和预后评估。然而，目前的方法具有侵入性，需要实时专业知识进行测量，或者受到动脉区域的限制。四维血流磁共振成像（4D Flow MRI）可通过估计局部脉搏波速度（PWV）来无创测量局部僵硬度。该技术可应用于以前只能通过侵入性僵硬度测量方法检测的血管区域。MRI的PWV数据也可在检查后进行分析。然而，4D Flow MRI在用于体内测量局部PWV之前需要进行验证。
将通过4D Flow MRI和台式实验计算得到的PWV与体外模型的彼得森弹性模量（PEM）进行比较。使用高速摄像机图像和压力传感器计算PEM。分析了三种渡越时间算法在PWV测量准确性和精度方面的表现。
4D Flow MRI和参考台式实验得到的PWV与PEM显示出很强的相关性（R = 0.99）。互相关渡越时间算法在4D Flow MRI和台式实验之间显示出最低的百分比差异（4 - 7%），而50%上升段点对点算法在渡越时间与距离数据的平均相关性方面最高（R = 0.845）。
4D Flow MRI是在简单体外模型中估计局部PWV的可行方法，也是临床分析的可行工具。此外，渡越时间算法的选择取决于血流波形形状和动脉区域。本研究加强了4D Flow MRI在简单模型中测量局部PWV的有效性。然而，该技术在用于体内之前需要在更复杂的模型中进行验证。
