迭代重建和滤波反投影重建在脑实质血肿低辐射剂量CT 复查中的应用

Application of iterative reconstruction in comparison with filtered back projection in low-dose CT re-scanning of intracerebral hematoma

摘要:

目的 比较迭代重建（IR）滤波反投影重建（FBP）在脑实质血肿低辐射剂量CT 复查中的应用 优劣。方法 选取病程1 周内的脑实质血肿头部CT 复查的成人90 例，随机分为3 组，每组各30 例。分别进行 100、150、200 mAs 3 种不同辐射剂量水平的CT 扫描。图像分别进行IR 和FBP，比较不同剂量组的两种重建 方式下脑实质血肿所在层面图像的噪声水平，并对图像质量进行主观评分。结果 ①相同辐射剂量的图像噪 声IR 组低于FBP 组（P <0.05）；② IR 图像100 mAs 组与200 mAs 组主观评分差异无统计学意义（P >0.05）， 100 mAs 组噪声高于200 mAs 组（P <0.05）；③ FBP 100 mAs 组图像质量低于200 mAs 组，主观评分和噪声差 异有统计学意义（P <0.05）；④ FBP 图像150 mAs 组与200 mAs 组主观评分差异无统计学意义（P >0.05）， 150 mAs 组噪声高于200 mAs 组（P <0.05）。结论 相同辐射剂量IR 较FBP 图像噪声更小，图像主观评分相同 时IR 较FBP 所需的辐射剂量更低。对成人脑实质血肿病变的CT 复查患者，IR 较FBP 具有更低辐射剂量的优 势，IR 可采用100 mAs，而FBP 需采用150 mAs。

Abstract:

Objective To assess the feasibility and advantage of iterative reconstruction (IR) in low-dose CT (LDCT) scanning of cerebral hemorrhage. Methods Totally 90 adult patients with cerebral hemorrhage in a week who needed CT re-scanning were chosen at random for a study of IR in LDCT. They were divided into three groups respectively with radiation dose levels of 100 mAs, 150 mAs and 200 mAs for head CT scanning. Then, IR and filter back projection (FBP) reconstructionwere used. Paired sample t test was applied to evaluate the difference in the image quality between different reconstruction modes in different dose groups. Results For review cases with cerebral hemorrhage: there were statistically significant differences in image noise level between the two reconstructed groups in each dose group (P < 0.05); between 100 mAs dose and 200 mAs dose groups of IR, there were no significant differences in image quality score (P > 0.05), but there was significant difference in image noise level (P < 0.05); between 100 mAs dose and 200 mAs dose groups of FBP, there were significant differences in image quality score and image noise level (P < 0.05); between 150 mAs dose and 200 mAs dose groups of FBP, there was no significant difference in image quality score (P > 0.05), but there was significant difference in image noise level (P < 0.05). Conclusions IR algorithm can achieve lower image noise level than FBP in the same dose manner of head CT scanning; IR has lower radiation dose than FBP with the same image subjective score. IR has the advantage of lower radiation dose than FBP (100 mAs versus 150 mAs ) on head CT re-scanning of patients with cerebral hemorrhage.