摘要
目的探讨自适应统计迭代重建技术对泌尿系结石CT图像噪声和质量的影响。方法应用宝石能谱CT对20例育龄人群尿路结石患者CT螺旋扫描。采用滤过反投影法和自适应迭代重建算法对原始数据进行重建,ASIR组分为20%、40%、60%、80%、100%ASIR重建5组图像。比较不同重建图像在同一层面的图像标准差（SD值）及平均CT值,并计算SNR和对比噪声比（CNR）,采用Liken5分制评估图像质量,通过Kappa方法评价观察者间的一致性。结果客观分析：（1）20%∽100%ASIR图像的SD值小于FBP组（P〈0.05）;（2）40%∽100%ASIR各组图像SNR、CNR值高于FBP组（P均〈0.05）。主观分析：（1）图像评定结果的观察者间一致性中等（Kappa=0.412）;（2）40%∽100%ASIR图像评分值高于FBP组（P〈0.05）。其中60%∽100%ASIR图像评分较高。结论与FBP相比,ASIR技术可降低肾结石CT噪声,有效改善图像质量;ASIR取值为60%∽100%时可获得最佳图像质量。
Objective To investigate the impact of adaptive statistical iterative reconstruction technique on image quality and image noise of Urinary calculi.Methods20 patients in childbearing age underwent Urinary calculi CT scan using Gemstone Spectral CT （Discovery CT 750 HD）. The raw data were reconstructed with filtered back projection and ASIR（20%∽100% ASIR, step 20%）, respectively. The standard deviation （SD value） and average CT value were measured on the same level of different reconstructed images. then the SNR and contrast to noise ratio were calculated. Image quality was evaluated using a 5-point scale. Kappa method was used to evaluate the consistency between the assessment res ults of two observers. The results of FBP and ASIR were analyzed by variance analysis, and correlation analysis was made between image noise and ASIR.ResultsObjective analysis： （1） SD values on 20%∽100% ASIR images were smaller than on FBP images （P〈0.05）. In comparison with FBP, SD values red uced ASIR images, respectively. （2） SNRand CNR values on 40%∽100% ASIR images were larger than those on FBP images（ allP〈0.05）. （1） The assessment scores between two observers obtained medium consistency in subjective image evaluation（Kappa=0.412）. （2） There were significant differences in assessment scores between 40%∽100%ASIR and FBP, while 60%∽100%ASIR images had higher scores.Conclusion Compared with FBP＆#183;ASIR technique can result in noise reduction and image quality improvement of Urinary calculi.Reconstruction using 60%∽100% ASIR values can significantly improve t image quality.
出处
《中国医药科学》
2015年第11期147-149,共3页
China Medicine And Pharmacy
关键词
统计迭代
体层摄影术
螺旋计算机
尿路结石
噪声
图像质量
Herative reconstruction
Tomography
Spiral computed
Urinary calculi
Noise
Image quality
