Department of Radiology and Biomedical Imaging, University of California, San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628, USA.
Radiology. 2011 Dec;261(3):923-9. doi: 10.1148/radiol.11110617. Epub 2011 Oct 3.
To determine whether flow velocity can be measured by using projection data from computed tomographic (CT) scans obtained during contrast material injection in a phantom model.
The authors constructed a 12.7-mm-diameter single-channel flow phantom with constant water flow velocity settings of 25.3, 43.9, and 70.5 cm/sec. For each flow velocity, serial axial scans were obtained with 16-section multidetector CT while a 10-mL bolus of contrast material was injected upstream of the imaging plane. For each bolus injection, the CT projection data from the scan with the sharpest increase in magnitude of detected contrast material was used for flow velocity measurements. Flow velocity was calculated as the ratio of distance between CT detector rows and the corresponding time lag in the contrast enhancement curves and was correlated with the reference velocities. Five separate contrast material injections and CT measurements were made for each flow velocity setting.
The correlation coefficient between the CT measurements of flow velocity and the reference measurements was 0.98 (P < .05). The mean CT measurements of flow velocity were 34.2, 53.9, and 80.8 cm/sec for slow, moderate, and fast velocity settings, respectively, overestimating the corresponding actual flow velocities by 26%, 18%, and 13% and showing precision values (coefficients of variation) of 5.2%, 3.7%, and 6.6%.
Flow velocity can be measured from row-to-row multidetector CT projectional data obtained during a single gantry revolution as a bolus of contrast material flows through a vascular phantom. With further development, this novel technique could potentially provide physiologic information to complement the anatomic CT angiographic findings of vascular disease.
在体模模型中，通过对比剂注射期间获取的计算机断层扫描（CT）投影数据，确定是否可以测量流速。
作者构建了一个直径为 12.7 毫米的单通道流量体模，流速设置为 25.3、43.9 和 70.5 cm/sec。对于每个流速，在对比剂团块注射到成像平面上游的情况下，使用 16 层多排 CT 进行连续轴向扫描。对于每个团注，使用检测到的对比材料幅度增加最明显的扫描的 CT 投影数据进行流速测量。流速被计算为 CT 探测器行之间的距离与对比增强曲线中相应的时间滞后的比值，并与参考速度相关联。对于每个流速设置，进行了五次单独的对比剂注射和 CT 测量。
CT 测量的流速与参考测量值之间的相关系数为 0.98（P <.05）。对于慢、中、快流速设置，CT 测量的流速分别为 34.2、53.9 和 80.8 cm/sec，分别高估了相应的实际流速 26%、18%和 13%，且显示出精度值（变异系数）为 5.2%、3.7%和 6.6%。
当对比剂团块流经血管体模时，从单个机架旋转期间的行到行多排 CT 投影数据可以测量流速。随着进一步的发展，这项新技术有可能提供生理信息，以补充血管疾病的解剖 CT 血管造影发现。
