宽体探测器CT探测器组合对影像分辨力影响的实验研究  

The experimental study of the effect of detector combination on image resolution in wide-detector CT

作　　者：郭森林[1] 任悦[1] 张永县[1] 张宗锐[1] 虞滨滨[1] 刘丹丹[1] 牛延涛[1] Guo Senlin;Ren Yue;Zhang Yongxian;Zhang Zongrui;Yu Binbin;Liu Dandan;Niu Yantao(Department of Radiology,Beijing Tongren Hospital,Capital Medical University,Beijing 100730,China)

机构地区：[1]首都医科大学附属北京同仁医院放射科,北京100730

出　　处：《中华放射医学与防护杂志》2022年第5期396-399,共4页Chinese Journal of Radiological Medicine and Protection

摘　　要：目的探讨宽体探测器CT在使用不同扫描模式、探测器宽度以及不同探测器位置时对影像高、低对比度分辨力的影响。方法使用GE Revolution CT,在固定CT容积剂量指数(CTDIvol)情况下对Catphan600模体的高、低对比度分辨力模块进行扫描。逐层扫描模式时,分别选择40、80、160 mm探测器宽度,用探测器的足侧边缘、中心和两圈扫描的相邻区域对分辨力模块进行成像。螺旋扫描模式时,探测器宽度/螺距组合分别为40 mm/0.516、40 mm/0.984、80 mm/0.508、80 mm/0.9924组,对位于扫描野的足侧边缘和中心的分辨力模块进行成像。由2名医生读取模体图像,评估高、低对比度分辨力。结果逐层扫描模式下探测器宽度为80、160 mm时两圈扫描相邻区域,以及螺旋扫描螺距为0.5时,所得影像高对比度分辨力为8 LP/cm,其余各探测器组合时均为7 LP/cm。逐层扫描时80、160 mm探测器足侧边缘区域所得影像1%低对比度可分辨直径为3 mm,其余条件时可分辨直径为2 mm。螺旋扫描模式40 mm探测器宽度、螺距0.516时所得影像1%低对比度可分辨直径为2 mm。随着探测器变宽,螺距变大,可分辨直径变大。结论宽体探测器CT不同扫描模式、探测器宽度、探测器中的不同位置以及螺距会对影像的高、低对比度分辨力产生一定影响,在临床实践中应根据实际需求进行选择。Objective To investigate the effect of different scanning modes,detector width and location in detector on high and low contrast resolution of wide-detector CT image.Methods The Catphan600 phantom with high and low contrast resolution modules was scanned with GE Revolution CT at the same CTDIvol.The scans were performed with the detector widths of 40,80 and 160 mm for sequential scanning mode and with the detector width/pitch combinations of 40 mm/0.516,40 mm/0.984,80 mm/0.508 and 80 mm/0.992 for spiral scanning mode.The resolution modules were placed at the adjacent region between two sequential scans,central and foot side edge in the longitudinal scanning range seperately.The subjective evaluation of the high and low contrast resolution was performed by two radiologists.Results The high contrast resolution was 8 LP/cm at adjacent region between two sequential scans with the detector width of 80 mm or 160 mm in sequential scanning mode,and at the pitch of 0.5 in spiral scanning mode,while it was 7 LP/cm for the rest of detector combinations.The distinguishable diameter was 3 mm at 1%low contrast resolution at foot side edge with the detector widths of 80 mm or 160 mm in the sequential scanning mode,and it was 2 mm for all the other conditions.The distinguishable diameter was 2 mm at 1%low contrast resolution with the detector width of 40 mm and pitch 0.516 in the spiral scanning mode and it was worse with the wider detector and larger pitch.Conclusions For the wide-detector CT,scanning mode,detector width,location in detector and pitches will affect the high and low contrast resolution to some degree.Appropriate selection should be done according to actual needs in clinical practice.

关 键 词：宽体探测器CT 对比度分辨力 扫描模式 

分 类 号：R814[医药卫生—影像医学与核医学]