评价迭代重建法与滤过反投影法在冠状动脉CTA检查中的价值

目的：对行冠状动脉CTA检查的患者原始数据应用低剂量自适应迭代重建技术（AIDR ）与滤过反投影法（FBP ）两种方法的图像进行比较，旨在了解迭代重建算法的图像质量及其临床应用价值。方法：26例临床疑似稳定性心绞痛患者采用320排CT行冠状动脉CTA检查。利用AIDR 重建的常规X线剂量方案扫描，对采集得到的原始数据分别用AIDR和FBP两种方法进行图像重建。测量升主动脉开口、右冠状动脉近段、左冠状动脉主干、右冠状动脉中段、左前降支近段及左回旋支近段的CT值、背景SD并计算分析SNR、CNR值。比较两者的图像质量。结果：26例患者都在一次心动周期完成冠状动脉检查。在血管各节段测得的平均CT值差异无统计学意义（P＞0．05），背景SD值的差异有统计学意义（P＜0．001），计算得到的SNR、CNR差异有统计学意义（P＜0．001）。两组图像质量的主观评分差异有统计学意义，AIDR （3．73±0．49）、FBP（3．59±0．61）（P＜0．01）。结论：应用AIDR重建法的图像质量优于FBP 重建法，迭代重建技术可明显降低图像噪声，改善影像质量并具有降低辐射剂量的作用。

Evaluation of iterative AIDR and filtered back projection image algorithm on coronary computed tomography angiography

Objective：To compare the image qualities of coronary computed tomography angiography （CCTA）using adaptive iterative dose reduction （AIDR）and filtered back projection （FBP）algorithm and to evaluate the clinical value of AIDR.Methods：Twenty-six patients with suspected stable angina underwent regular radiation dose scanning protocol on 320 MDCT scanner.The collected raw data were then reconstructed with AIDR and FBP respectively.CT value and background SD value were measured at the aorta root,proximal and middle right coronary artery,left main coronary artery,proximal left anterior artery,as well as proximal left circumflex artery.SNR and CNR were also calculated.Two observers compared the quality of the images with subjective grading.Results：Twenty-six patients completed CCTA within one heart beat.The average CT attenuation measured at segments of coronary arteries was not statistically different （P〉0.05）.Back-ground SD value,SNR and CNR calculated were statistically different （P〈0.001）.The subjective grading of image qualities between two groups were 3.73±0.49 for AIDR and 3.59±0.61for FBP,respectively,and was statistically different （P〈0.01）.Conclusion：The quality of images reconstructed with AIDR was better than that of FBP.AIDR can reduce the imaging noise significantly,improve the image quality and help reducing radiation dose potentially.