Yang C-Y, Chen Y-F, Lee C-W, Huang A, Shen Y, Wei C, Liu H-M
Department of Medical Imaging, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
AJNR Am J Neuroradiol. 2008 Aug;29(7):1288-95. doi: 10.3174/ajnr.A1073. Epub 2008 Apr 10.
Conventional CT angiography (CTA) is acquired during only a short interval in the arterial phase, which limits its ability to evaluate the cerebral circulation. Our aim was to compare the image quality and radiation dose of conventional single-phase CTA (SP-CTA) with a multiphase CTA (MP-CTA) algorithm reconstructed from a perfusion CT (PCT) dataset.
Fifty consecutive patients undergoing head CTA and PCT in 1 examination were enrolled. The PCT dataset was obtained with 40.0-mm-detector coverage, 5.0-mm axial thickness, 80 kilovolt peak (kVp), 180 mA, and 30 mL of contrast medium. MP-CTA was reconstructed from the same PCT dataset with an axial thickness of 0.625 mm by using a new axial reconstruction algorithm. A conventional SP-CTA dataset was obtained with 0.625-mm axial thickness, 120 kVp, 350 mA, and 60 mL of contrast medium. We compared image quality, vascular enhancement, and radiation dose.
SP-CTA and MP-CTA of 50 patients (male/female ratio, 31/19; mean age, 59.25 years) were analyzed. MP-CTA was significantly better than SP-CTA in vascular enhancement (P = .002), in the absence of venous contamination (P = .006), and was significantly higher in image noise (P < .001). MP-CTA used less contrast medium than SP-CTA and could demonstrate hemodynamic information. The effective dose of MP-CTA was 5.73 mSv, which was equal to that in conventional PCT, and it was 3.57 mSv in SP-CTA.
It is feasible that MP-CTA may provide both CTA and PCT results. Compared with SP-CTA, MP-CTA provides comparable image quality, better vascular enhancement, hemodynamic information, and more noise with less detail visibility with a lower tube voltage. The radiation dose of MP-CTA is higher than that of SP-CTA, but the dose can be reduced by altering the sampling interval.
传统CT血管造影（CTA）仅在动脉期的短时间间隔内采集，这限制了其评估脑循环的能力。我们的目的是比较传统单相CTA（SP-CTA）与从灌注CT（PCT）数据集重建的多相CTA（MP-CTA）算法的图像质量和辐射剂量。
纳入50例在一次检查中同时接受头部CTA和PCT的连续患者。PCT数据集采用40.0毫米探测器覆盖范围、5.0毫米轴向层厚、80千伏峰值（kVp）、180毫安和30毫升造影剂获得。通过使用新的轴向重建算法，从相同的PCT数据集中重建轴向层厚为0.625毫米的MP-CTA。采用0.625毫米轴向层厚、120 kVp、350毫安和60毫升造影剂获得传统SP-CTA数据集。我们比较了图像质量、血管强化和辐射剂量。
分析了50例患者（男/女比例为31/19；平均年龄59.25岁）的SP-CTA和MP-CTA。MP-CTA在血管强化方面显著优于SP-CTA（P = 0.002），在无静脉污染方面（P = 0.006），且图像噪声显著更高（P < 0.001）。MP-CTA比SP-CTA使用的造影剂更少，并且能够显示血流动力学信息。MP-CTA的有效剂量为5.73毫希沃特，与传统PCT相等，而SP-CTA为3.57毫希沃特。
MP-CTA可能同时提供CTA和PCT结果是可行的。与SP-CTA相比，MP-CTA提供了相当的图像质量、更好的血管强化、血流动力学信息以及更多噪声，细节可见度较低，管电压较低。MP-CTA的辐射剂量高于SP-CTA，但可以通过改变采样间隔来降低剂量。
