Purpose: Based on the mathematical model of maximum slope, to study the effect of reducing temporal resolution of dual source CT on the image quality and parameter of CT perfusion. Methods: The CT perfusion results of 36 cerebral ischemic cases were analyzed retrospectively. Two temporal resolutions: (1 frame/1.5s and 1 frame/3.0s) were used for the CT perfusion imaging. The image data were processed by VPCT software. Subjective visual evaluation was used to assess the image quality. In addition, the same location of the ROI for measurement of perfusion parameters were recorded and then the variabilities of the parameters were statistically analyzed. Results: (l)The visual scores of image quality of perfusion parameter maps were lowered when the temporal resolution was reduced, while the detection of lesion was not influenced. (2)Significance difference occurred in the perfusion parameters following by temporal resolution reducing (P<0.05). However, no significant in relative values (P>0.05). Conclusion: Reducing of temporal resolution in a certain range will not affect the detection of ischemic lesions and will be benefit for clinical study. However, it is recommended to use a higher temporal resolution to study the perfusion parameters.%目的:基于最大斜率法数学模型,探讨降低时间分辨率对灌注图像质量及参数的影响.方法:对36例具有脑缺血症状患者的CT灌注成像资料进行回顾性分析.分别选择1帧/1.5s和1帧/3s时间分辨率进行图像处理,对两组图像质量进行主观视觉评价,然后对同一病例选取相同的感兴趣区域进行灌注参数测量,并进行统计学分析.结果:①降低时间分辨率对灌注图像的视觉评分有一定影响,但不影响病灶检出.②各灌注参数绝对值随时间分辨率的降低变化有统计学意义(P＜0.05),而参数相对值差异无统计学意义(P＞0.05).结论:在一定范围内降低时间分辨率不影响缺血病灶的检出,可以满足临床需要；但若对灌注参数值进行研究,建议使用较高时间分辨率.
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