高分辨靶重建模式优化宝石CT成像
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摘要
目的以体模实验为基础,观察高分辨靶重建模式优化宝石CT成像的价值。方法采用宝石CT不同的扫描野(SFOV;50cm vs 32cm)对Catphan 500体模分别进行高分辨和非高分辨模式扫描,并对原始数据以相同大小的显示野(25cm)进行STAND算法重建成像。根据不同成像方式,将所有图像分为SFOV 50cm+非高分辨组(A组)、SFOV50cm+高分辨组(B组)、SFOV 32cm+非高分辨组(C组)和SFOV 32cm+高分辨组(D组),测量并比较各组图像噪声、SNR、CNR、空间分辨率、密度分辨率及CT剂量指数(CTDI)。结果 4组噪声、SNR、CNR、空间分辨率、密度分辨率及CTDI差异均有统计学意义(P均<0.05)。C组较A组噪声增加(P<0.01);与A组比较,B组空间分辨率提高,D组CNR、SNR均降低(P均<0.01),且噪声升高(P<0.01)。结论选择高分辨靶重建模式,不增加图像噪声,并可保证对比噪声比和信噪比,提高空间分辨率。
Objective To explore the value of high resolution reconstruction for optimization of imaging quality of GE Discovery CT 750 HD based on phantom pilot.Methods CT scanning with large(50 cm)and small(32 cm)scanning field of view(SFOV)was performed for a Catphan 500 phantom with or without high resolution on GE Discovery CT 750 HD.All raw data acquired by volumetric CT scan were reconstructed as the same size of a small DFOV(25 cm)with STAND algorithm.Then the images were divided into four groups,including large SFOV without high resolution(group A),large SFOV with high resolution(group B),small SFOV without high resolution(group C)and small SFOV with high resolution(group D).The spatial-resolution(SR),density-resolution(DR),noise(N),CNR,SNR and CT dose index volumes(CTDI)were measured and compared among 4 groups.Results The overall differences of SR,DR,N,CNR,SNR and CTDI were statistically significant among four groups(all P<0.05).Compared with group A,the average N increased in group C(P<0.01),SR increased in group B and the average CNR and SNR decreased in group D,while N increased in group D(all P<0.01).Conclusion Large SFOV combined with high resolution reconstruction may ensure CNR and SNR,and improve SR.
Objective To explore the value of high resolution reconstruction for optimization of imaging quality of GE Discovery CT 750 HD based on phantom pilot.Methods CT scanning with large(50 cm)and small(32 cm)scanning field of view(SFOV)was performed for a Catphan 500 phantom with or without high resolution on GE Discovery CT 750 HD.All raw data acquired by volumetric CT scan were reconstructed as the same size of a small DFOV(25 cm)with STAND algorithm.Then the images were divided into four groups,including large SFOV without high resolution(group A),large SFOV with high resolution(group B),small SFOV without high resolution(group C)and small SFOV with high resolution(group D).The spatial-resolution(SR),density-resolution(DR),noise(N),CNR,SNR and CT dose index volumes(CTDI)were measured and compared among 4 groups.Results The overall differences of SR,DR,N,CNR,SNR and CTDI were statistically significant among four groups(all P<0.05).Compared with group A,the average N increased in group C(P<0.01),SR increased in group B and the average CNR and SNR decreased in group D,while N increased in group D(all P<0.01).Conclusion Large SFOV combined with high resolution reconstruction may ensure CNR and SNR,and improve SR.
引文
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[2]Hansell DM.Thin-section CT of the lungs:The Hinterland of normal.Radiology,2010,256(3):695-711.
[2]高燕莉,翟仁友,张镭,等.64排CT容积HRCT扫描方案优化的模具研究.中国医学影像技术,2008,24(4):614-617.
[4]张璞,孙加宇,李姣,等.医用CT体模对高对比度分辨力检测结果的影响.中国医疗设备,2016,31(11):37-49.
[5]Hansell DM.Thin-section CT of the lungs:The Hinterland of normal.Radiology,2010,256(3):695-711.
[6]胡敏霞,赵心明,宋俊峰等.64层螺旋CT腹部扫描参数优化的初步研究.中华放射学杂志,2011,45(3):264-269.
[7]Honda O,Johkoh T,Tomiyama N,et al.High-resolution CTusing multidetector CT equipment:Evaluation of image quality in11cadaveric lungs and a phantom.AJR Am J Roentgenol,2001,177(4):875-879.
[8]Verdun FR,Denys A,Valley JF,et al.Detection of low-contrast objects:Experimental comparison of single-and multi-detector row CT with a phantom.Radiology,2002,223(2):426-431.
[9]卢东生,李铁一.CT图像质量的影响因素及高分辨率CT图像扫描参数的选择.中华放射学杂志,1998,32(6):410-413
[10]林意群,冯晓刚,洪德明,等.用Catphan体模进行CT机的QA检测方法研究.中国医学物理学杂志,1999,16(3):161-164
[11]康立丽,余晓锷,冯晓刚,等.X-CT设备低对比度分辨力检测方法研究与分析.放射学实践,2003,18(5):366-368.
[12]Siegel MJ,Schmidt B,Bradley D,et al.Radiation dose and image quality in pediatric CT:Effect of technical factors and phantom size and shape.Radiology,2004,233(2):515-522.
[13]Ravenel JG,Leue WM,Nietert PJ,et al.Pulmonary nodule volume:Effects ofreconstruction parameters on automated measurements-aphantom study.Radiology,2008,247(2):400-408.