CAJ | 학술논문

目的：研究IRIS迭代重建技术与CARE dose 4D自动毫安控制相结合在肝脏平扫中对提高图像质量、降低辐射剂量的影响。方法（1）尸体标本研究：采用130 kV，mAs为250～30（每次递减20）的扫描参数对尸体标本上腹部进行扫描，对扫描后的原始数据分别进行IRIS与FBP重建，经测量分析后选择低剂量扫描IRIS重建后图像的噪声与常规剂量扫描FBP重建噪声相等的扫描条件进行临床研究。（2）临床研究：120例进行肝脏CT平扫的患者随机分为A、B 2组，每组60例。 A组采用130 kV、图像质量控制参考毫安秒150 mAs自动毫安控制进行扫描，分别进行IRIS与FBP重建；B组采用130 kV、250 mAs进行扫描，分别进行IRIS与FBP重建。记录2组患者CT容积剂量指数（CTDIvol）及剂量长度乘积（DLP）。由3名医师采用盲法对4组图像进行噪声测量、对比噪声计算等客观评价及主观图像质量评价。结果尸体标本研究得到规律：低剂量扫描IRIS重建后图像的噪声与常规剂量扫描FBP重建噪声相等时mAs可降低至150 mAs。将其应用到临床，临床研究扫描剂量为：A 组CTDIvol 为2?．35～16．3 mGy；DLP为63．4～287．5 mGycm。 B组CTDIvol为25．7 mGy；DLP为523．8～586．6 mGycm。 A组较B组降低了50％～70％。 A1、B1、B23组图像质量均满足临床诊断要求。 B1图像质量高于B2图像质量，A1图像质量与B2差异无统计学意义（ P＞0．05），A2图像质量最差，不能满足诊断需要。结论迭代技术与自动毫安控制相结合相同剂量条件下可以提高图像质量，在保证图像质量条件下可以降低肝脏平扫的辐射剂量，值得临床推广。
목적：연구IRIS질대중건기술여CARE dose 4D자동호안공제상결합재간장평소중대제고도상질량、강저복사제량적영향。방법（1）시체표본연구：채용130 kV，mAs위250～30（매차체감20）적소묘삼수대시체표본상복부진행소묘，대소묘후적원시수거분별진행IRIS여FBP중건，경측량분석후선택저제량소묘IRIS중건후도상적조성여상규제량소묘FBP중건조성상등적소묘조건진행림상연구。（2）림상연구：120례진행간장CT평소적환자수궤분위A、B 2조，매조60례。 A조채용130 kV、도상질량공제삼고호안초150 mAs자동호안공제진행소묘，분별진행IRIS여FBP중건；B조채용130 kV、250 mAs진행소묘，분별진행IRIS여FBP중건。기록2조환자CT용적제량지수（CTDIvol）급제량장도승적（DLP）。유3명의사채용맹법대4조도상진행조성측량、대비조성계산등객관평개급주관도상질량평개。결과시체표본연구득도규률：저제량소묘IRIS중건후도상적조성여상규제량소묘FBP중건조성상등시mAs가강저지150 mAs。장기응용도림상，림상연구소묘제량위：A 조CTDIvol 위2?．35～16．3 mGy；DLP위63．4～287．5 mGycm。 B조CTDIvol위25．7 mGy；DLP위523．8～586．6 mGycm。 A조교B조강저료50％～70％。 A1、B1、B23조도상질량균만족림상진단요구。 B1도상질량고우B2도상질량，A1도상질량여B2차이무통계학의의（ P＞0．05），A2도상질량최차，불능만족진단수요。결론질대기술여자동호안공제상결합상동제량조건하가이제고도상질량，재보증도상질량조건하가이강저간장평소적복사제량，치득림상추엄。
Objective To investigate the influence of iterative reconstruction algorithm ( IRIS) combined with CARE dose 4D on reducing radiation dose and improving image quality in liver CT .Methods (1) Human cadaver study :human cadaver was scanned for twelve times by emotion 16-slice CT scanner with same tube voltage 130 kV and different tube currents from 30mAs to 250mAs with increment of 20mAs.The images were reconstructed with IRIS and FBP respectively ,and the data were analyzed before clinical study .(2)Clinical study:120 patients were randomly divided into two groups ,group A and group B,with 60 patients in each group.The patients in group A received liver CT (130kV,CARE dose 4D and reference mAs of 150),and images were reconstructed with IRIS and FBP ,redpectively.The patients in group B were scanned by CT (130kV, reference mAs of 250),and images were reconstructed with IRIS and FBP respectively .CT dose index volumes (CTDIvol), dose length product ( DLP) were recorded .The image quality was evaluated by three radiologists blindly with objective methods (noise measurement and CNR calculating etc ) as well as subjective methods.Results CTDIvol and DLP were 2.35 ~16.3mGy and 63.4~287.5mGycm,respectively,in group A,however,which were 25.7mGy and 523.8~586.6mGycm in group B,respectively,which in group A were decreased by 50%~70%.Image quality in both group A1,group B1,group B2 met diagnostic requirements .The image quality in group B1 was better than that of group B2,however,there was no significant difference in image quality between group A1 and group B2 ( P >0.05).The image quality in group A2 was the worst,which could not meet diagnostic requirements .Conclusion IRIS combined CARE dose 4D can improve the image quality under the condition of the same dose , which can reduce the radiation dose of liver CT under the condition of guaranteeing the image quality,so it is worthy of clinical spreading application .