Buonocore M H, Bogren H
Division of Diagnostic Radiology, University of Davis Medical Center, Sacramento, California 95817.
Magn Reson Med. 1992 Jul;26(1):141-54. doi: 10.1002/mrm.1910260115.
Velocity-encoded phase contrast imaging is being used increasingly in clinical imaging for quantization of blood flow. In this study, the accuracy and precision of ascending aorta flow measurements were found to depend on several subtle aspects of the scan prescription and image analysis. While the usual scan parameters such as TR, TE, and flip angle gave incremental changes in the flow measurements, four additional factors that had a much greater effect on the measurements were identified. These factors were (1) the zero velocity (background) pixel value, (2) the size and shape of the vessel region of interest, (3) the maximum velocity encoded in diastole, and (4) the temporal resolution. Statistical analysis was done on a total of 48 scans on nine normal subjects to confirm the significance of the measured differences using the various choices for each of these factors. These factors must be considered if accurate and precise measurements of blood flow are desired. Estimates of accuracy and precision suggest that quantitative flow measurements from velocity-encoded MR imaging can be clinically useful.
速度编码相位对比成像在临床成像中越来越多地用于血流定量分析。在本研究中，发现升主动脉血流测量的准确性和精确性取决于扫描方案和图像分析的几个微妙方面。虽然诸如重复时间（TR）、回波时间（TE）和翻转角等常用扫描参数在血流测量中会产生增量变化，但还确定了另外四个对测量有更大影响的因素。这些因素包括：（1）零速度（背景）像素值；（2）感兴趣血管区域的大小和形状；（3）舒张期编码的最大速度；（4）时间分辨率。对9名正常受试者的48次扫描进行了统计分析，以确认使用这些因素中每个因素的不同选择所测得差异的显著性。如果需要准确和精确的血流测量，就必须考虑这些因素。准确性和精确性的估计表明，速度编码磁共振成像的定量血流测量在临床上可能是有用的。
