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

摘要

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 back-ground SD value were measured at the aorta root,proximal and middle right coronary artery,left main coronary artery,prox-imal left anterior artery,as well as proximal left circumflex artery.SNR and CNR were also calculated.Two observers com-pared 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 ima-ging noise significantly,improve the image quality and help reducing radiation dose potentially.%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。