| 高建华,孙宪昶,李剑颖,王贵生,李娜,戴汝平.后置滤过器C2对64层螺旋CT冠状动脉成像质量的影响[J].中国医学影像技术,2007,23(1):73~76 |
| 后置滤过器C2对64层螺旋CT冠状动脉成像质量的影响 |
| Influence of a post-processing filter on image quality of cardiac scans using 64-slice spiral CT |
| 投稿时间：2006-09-05 修订日期：2006-12-25 |
| DOI： |
| 中文关键词: 冠状血管 体层摄影术 X线计算机 血管造影术 滤过器 |
| 英文关键词:Coronary vessels Tomography, X-ray computed Angiography Filter |
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| 摘要点击次数: 1562 |
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| 中文摘要: |
| 目的 探讨LightSpeed VCT后置滤过器C2在冠状动脉成像中对图像质量和噪声的影响,以期获得在保证优良图像质量的前提下降低射线剂量的可行性依据。方法 随机选取30例患者(男19例,女11例,平均年龄59.4岁)行64层螺旋CT冠状动脉成像。使用GE LightSpeed VCT机,采用120 kV,640 mA,0.35 s/360°,层厚0.625 mm,pitch 0.22~0.24,Bowtie选用large body模式。采像后对每例原始图像分别进行使用后置滤过器C2和不使用C2的重建,得到有/无C2后处理的两组图像(UC2组和NUC2组)。①由两名有经验的影像科医师以双盲法对两组图像从冠脉节段的显示数目、细小分支显示率、血管边缘锐利度、血管内对比剂清晰度四个方面以1~4分(4分为优)进行图像质量评分,评分有分歧的由两人共同商讨后达成一致;②分别选取两组图像中面积相等的感兴趣区(ROI ,面积为100 mm2),在相同轴位图像上(均为左冠状动脉主干自左窦发出的层面)测量升主动脉中心部的噪声值(均值及标准差),比较UC2组和NUC2组图像噪声;③对两组图像质量评分及噪声值差异进行t检验,P<0.05视为有统计学意义。结果 ①UC2组和NUC2组图像质量评分分别为(3.71±0.31)分、(3.72±0.29)分,两组间无显著性差异(P>0.05);②UC2组和NUC2组噪声值均值分别为22.13±4.21、27.08±4.74,UC2组较NUC2组的图像噪声下降约18%,两组间有显著性差异(P<0.01)。结论 64层螺旋CT冠脉成像中使用后置滤过器C2 重建,可在不增加曝光剂量的情况下降低图像噪声、提高图像质量,由此为进一步降低射线剂量的研究提供了可能性。 |
| 英文摘要: |
| Objective To evaluate the influence of an adaptive post-processing filter (C2) on CT cardiac images and to gain confidence for future dose reduction with same current image quality. Methods Thirty patients (19 male and 11 female, average age of 54.4) were underwent cardiac scans using GE LightSpeed 64-slice VCT. The scan techniques were 120 kV, 0.35 s rotation speed, 0.22-0.24 pitch, body bowtie, 0.625 mm slice thickness. Cardiac images were reconstructed with the use of C2 (UC2) and without (NUC2) to create two image sets from the same patient. Two experienced radiologists were asked to quantitatively evaluate the image quality blindly in terms of the number of coronary arteries and smaller branches identified, the sharpness of vessel edges and the clarity of contrast agent in the vessel using scores of 1-4 with 4 being the highest. Image noises were also measured for the two sets with ROI of 100 mm2 placed in the same place at the center of the ascending aorta. We performed statistical analysis on the quality scores and the noise measurements from the two sets. Results The image quality scores for the UC2 and NUC2 sets were 3.71±0.31 and 3.72±0.29, respectively, it indicated no statistically significant difference (P>0.05). However, the mean and standard deviation of the noise measurements for the UC2 and NUC2 sets were 24.87, 2.60 and 30.05, 3.18, respectively. The images with UC2 filtering had 17% noise reduction compared to those without (P<0.01). Conclusion The adaptive post-processing filter provided with the GE LightSpeed VCT reduced the noise of CT cardiac images by 17% without adverse impact on other clinically relevant parameters. This noise reduction would be able to be translated into dose reduction to the patient with same image noise in the future. |
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