Block M, Liu Y H, Harris L D, Robb R A, Ritman E L
J Comput Assist Tomogr. 1984 Jun;8(3):390-400. doi: 10.1097/00004728-198406000-00004.
The accuracy in determining the three-dimensional anatomy of a vessel network by computed tomography (CT) is evaluated using a glass model of a pulmonary artery. The dynamic spatial reconstructor (DSR), a high temporal resolution, volumetric, roentgenographic, CT scanner, was used to scan the model. The glass of the model had a roentgen attenuation coefficient mu = 0.55 cm-1, which is approximately equivalent to the 20% dilution of contrast medium to be expected in the pulmonary arterial tree following a contrast agent bolus injection of 2 ml/kg in the right atrium. The model was scanned inside a 20 cm diameter Plexiglas cylinder with a 1 cm thick wall (mu congruent to 0.2 cm-1) to simulate the chest wall of a 20 kg dog, and it was filled with potato flakes to simulate lung parenchyma (mu congruent to 0.06 cm-1). In one 0.011 s scan, information for reconstruction of a stack of images of transaxial sections was recorded. Sequential scans were performed to obtain data for either maximum transaxial resolution (14 angles of view every 0.0167 s, 120 parallel slices each 1.8 mm thick) or maximum axial resolution (eight angles of view every 0.0167 s, 240 parallel slices each 0.9 mm thick) reconstructions. Estimated detectable "vessel" size, cross-sectional area, branching angle, and interbranch segment length were determined as a function of imaged slice thickness, orientation of section image, and number of angles of view (i.e., scan duration) used to make images. Retrospective selection of 0.05 s duration scan apertures at sequential 0.5 s intervals was used to simulate a typical, retrospectively gated reconstruction from a DSR scan. Using these reconstructed images, 2 mm diameter "vessels" could be readily detected and their structure quantitated. Comparing direct measurements and DSR estimates, cross-sectional area (SEE = 3 mm2), branching angles (SEE = 2 degrees), and segment length (SEE = 1 mm) all had a correlation coefficient greater than 0.99, and the regression lines showed no significant differences from the lines of identity (p greater than 0.05).
使用肺动脉玻璃模型评估通过计算机断层扫描（CT）确定血管网络三维解剖结构的准确性。动态空间重建仪（DSR）是一种具有高时间分辨率的容积式X射线CT扫描仪，用于扫描该模型。模型的玻璃具有X射线衰减系数μ = 0.55 cm-1，这大约相当于在右心房以2 ml/kg的剂量推注造影剂后，肺动脉树中预期的造影剂20%稀释度。该模型在直径20 cm、壁厚1 cm（μ约为0.2 cm-1）的有机玻璃圆筒内进行扫描，以模拟20 kg犬的胸壁，并且模型内填充薯片以模拟肺实质（μ约为0.06 cm-1）。在一次0.011 s的扫描中，记录了用于重建一系列横断面图像的信息。进行连续扫描以获取用于最大横断面分辨率（每0.0167 s 14个视角，120个平行切片，每个切片厚1.8 mm）或最大轴向分辨率（每0.0167 s 8个视角，240个平行切片，每个切片厚0.9 mm）重建的数据。根据成像切片厚度、切片图像方向以及用于成像的视角数量（即扫描持续时间），确定估计可检测的“血管”大小、横截面积、分支角度和分支间节段长度。以连续0.5 s的间隔对0.05 s持续时间的扫描孔径进行回顾性选择，以模拟从DSR扫描进行的典型回顾性门控重建。使用这些重建图像，可以轻松检测到直径2 mm的“血管”并对其结构进行定量分析。将直接测量值与DSR估计值进行比较，横截面积（标准误 = ３mm2）、分支角度（标准误 = 2°）和节段长度（标准误 = 1 mm）的相关系数均大于0.99，并且回归线与恒等线无显著差异（p＞0.05）。
