摘要:
Objective :Aim to evaluate the usage of low-dose CT scanning and iterative reconstruction in the accurate diagnosis of pulmonary embolism while decreasing the radiation dose and image quality not compromised . Methods :108 patients finally diagnosed as pulmonary embolism were reviewed and divided into three groups A ,B , and C .Patients in Group A were scanned under routine radiation dose (120kV ) and images were reconstructed by filtered back projection (FBP) ,while Group B radiation dose (100kV) ,FBP and Group C radiation dose (100kv) , iterative reconstruction (iDose) .the CT dose index volume (CTDI vol) ,dose length product (DLP) ,effective radia-tion dose (ED) ,The mean value of main pulmonary artery and dorsal muscles ,signaloise ratio (SNR) ,contrast noise ratio (CNR) of the images in each group were recorded and compared .The image quality were graded and scored 1-5 ,according to these parameters .Results :Under subjective evaluation ,the image quality in three groups has no significant difference .Under objective evaluation ,group A ,B and B ,C has statistical difference (P 0 .05)between group A ,C .Group B has the privilege of lower dose BUT louder noise and decreased SNR ,CNR ,compared with Group A .The image quality in Group C (iDose) surpassed that in group B (FBP) (P 0.05),A、B两组及B、C两组比较差异均有统计学意义(P<0.05).不同辐射剂量A、B两组比较,辐射剂量小,图像噪声相对增高,SNR及CNR减小.相同辐射剂量组,应用iDose迭代重建组(C组)图像质量均优于传统滤波反投影FBP组(B组)(P<0.01);辐射剂量评价中,低剂量组的有效辐射剂量(ED)较常规剂量组(A组)分别降低18.0% ~19.6%.结论:肺动脉栓塞患者行CTPA检查时,采用低辐射剂量并联合迭代重建算法重建,可以在保持肺动脉图像质量不降低的基础上,显著减少有效辐射剂量,为其临床应用与推广研究提供可靠的依据.