不同重建算法对低剂量头颈部CTA扫描图像质量的影响

摘要

Objective:To discuss the effect of different reconstruction algorithms for the image quality of the computed tomographic angiography (CTA) with low dose on head and neck through comparing the images obtained from different reconstruction algorithms, which included filtering and reflection projection technique (FBP), adaptive statistical iterative (ASIR) model and based on iterative reconstruction (MBIR) after CTA with low dose was applied on head and neck.Methods:30 patients who were implemented the CTA on head and neck were enrolled in this study. The gem energy spectrum CT was applied to scan their head and neck, and the tube voltage was set in low dose (80 kVp), and 60-80 mL contrast agent (350 mg I/mL) was injected in elbow vein as 4mL/s. The other parameters were chosen as routine requirement. The obtained original images were reconstructed by using FBP, 60% ASIR and MBIR, and then the three kinds images were compared and scored by using relative statistical analysis.Results: For the using of different reconstruction algorithms (FBP, 60% ASIR and MBIR), the results of image noise showed MBIR<60% ASIR60% ASIR>FBP, and the differences among them were significant. Finally, about the subjective score of image, the results showed MBIR>60% ASIR>FBP, and their differences also were significant.Conclusion: Under gem energy spectrum CT, the image noise of MBIR is lowest and its image quality is best, and it has diagnosis value and meaning in clinical practice.%目的:在头颈部低剂量血管造影(CTA)扫描后对得到的原始图像运用不同重建方法,即滤波反射投影(FBP)、自适应统计迭代(ASIR)和基于模型迭代重建(MBIR)获得的图像进行比较,探讨不同重建方法对头颈低剂量CTA扫描图像质量的影响.方法:选取30例行头颈部CTA检查的患者,应用宝石能谱CT进行头颈扫描,将管电压设置为低剂量80 kVp,于肘静脉以4 ml/s速度注射60~80 ml对比剂(350 mg I/ml),其余参数选择常规参数.对所得原始图像分别使用FBP、60%ASIR和MBIR进行重建,对三组重建获得的图像质量进行评分和比较,并做相应的统计学分析.结果:运用不同重建方法FBP、60%ASIR和MBIR,得到的图像噪声、对比噪声比以及图像质量主观得分结果显示:①图像噪声,MBIR组<60%ASIR组60%ASIR组>FBP,且差异显著;③图像主观评分,MBIR组>60%ASIR组>FBP,且差异明显.结论:在宝石CT下的头颈部CTA使用低剂量结合三组不同重建算法获得的图像中,MBIR重建获得的图像噪声最低,图像质量最好,具有临床诊断意义.