640层CT冠状动脉造影AIDR3D重建算法的图像质量及辐射剂量评价

Evaluation on image quality and radiation dose of 640-slice CT coronary arteriography with AIDR3D reconstruction algorithm

目的评价640层CT冠状动脉造影(CTCA)三维自适应迭代剂量降低(AIDR3D)重建算法的图像质量及辐射剂量。方法连续性84例患者接受640层CT自动曝光扫描冠状动脉造影检查,在图像后处理工作站分别采用AIDR3D、滤波反投影(FBP)算法对扫描的原始图像数据进行重建。2位不知道临床信息及重建算法并且富有经验的影像科医生独立测量、计算2种重建算法CTCA的图像噪声、信噪比和对比噪声比,4等级法定性评价CTCA的图像质量。根据CT机扫描输出的剂量长度乘积计算辐射剂量。统计分析比较2种重建算法CTCA的定量及定性图像质量。结果 AIDR3D重建算法CTCA的图像噪声为(27.20±4.40)HU,较FBP(60.00±12.40)HU减少了46.10%,信噪比21.10±5.10较FBP 11.40±2.80提高了84.70%,对比噪声比24.70±5.10较FBP 13.50±3.20提高了82.20%,二者比较均差异有统计学意义(P<0.05)。AIDR3D重建算法冠状动脉近部、中部、远部的图像质量定性评价分数分别为(3.90±0.30)、(3.70±0.50)、(3.60±0.60)分,均高于FBP[分别为(2.60±0.60)、(2.30±0.60)、(2.10±0.70)分],二者比较均差异有统计学意义(P<0.05)。AIDR3D、FBP重建算法可以用于诊断的冠状动脉总段数分别为1 216段(96.50%)、504段(40.00%),二者比较差异有统计学意义(P<0.05)。平均有效辐射剂量为(2.10±1.00)mSv。结论 640层CTCA AIDR3D重建算法不仅较常规的FBP重建算法的图像噪声显著减少,定量及定性图像质量均明显提高,而且有效辐射剂量低。

Objective To investigate the image quality and radiation dose of 640-slice CT coronary arteriography（CTCA）with adaptive iterative dose reduction three-dimensional（AIDR3D）reconstrucction algoritym.Methods 640-slice CTCA with automatic exposure was performed on 84 consecutive patients.The original image data were reconstructed with AIDR3 Dand the filtered back-projection（FBP）algorithms at the image postprocessing workstation.Two experienced radiologists without knowing clinical information and reconstruction algorithms independently measured and calculated the image noise,signal-to-noise ratio and contrastto-noise ratio with AIDR3 Dand FBP reconstruction algorithms.The qualitative image quality was assessed by using the 4-point scale.The radiation dose was calculated based on dose-length product exported on CT scanner.The quantitative and qualitative image quality with two kinds of reconstruction algorithm was analyzed statistically.Results The CTCA image noise was（27.20±4.40）HU with AIDR3Dand（60.00±12.40）HU with FBP,which with AIDR3 Dwas decreased by 46.10%than that with FBP;the signal-to-noise ratio was 21.10±5.10 with AIDR3 D and 11.40±2.80 with FBP,which with AIDR3 D was increased by84.70%than that with FBP;the contrast-to-noise ratio was 24.70±5.10 with AIDR3Dand 13.50±3.20 with FBP,which with AIDR3 Dwas raised by 82.20%than that with FBP,the differences in 3indexes between the two kinds of reconstruction algorithm were statistically significant（P〈0.05）.The CTCA qualitative image quality scores of proximal,middle and distal parts with AIDR3Dwere（3.90±0.30）,（3.70±0.50）and（3.60±0.60）respectively,which all were higher than（2.60±0.60）,（2.30±0.60）and（2.10±0.70）with FBP respectively,the differences in 3items between 2kinds of algorithm had statistical significance（P〈0.05）.The total segments which could be used to diagnose the CTCA images with AIDR3 Dand FBP algorithms were 1 216segments（96.50%）and 504segments（40.00%）,respectively,the difference had statistical significance（P〈0.05）.The mean effective radiation dose was（2.10±1.00）mSv.Conclusion 640-slice CTCA with AIDR3 Dreconstruction algorithm not only significantly reduces the image noise than the conventional FBP algorithm,improves the quantitative and qualitative image quality,but also decreases the effective radiation dose.