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目的比较多排螺旋CT颈动脉成像容积重建和最大密度投影重建在显示颈动脉病变方面的差异。方法随机选择临床病例及实验动物共72例行CT颈动脉成像,其中,30例通过随机区组分成2组,注射速率分别采用3ml/s、4ml/s,扫描层厚为1mm;另42例也随机分成2组,扫描层厚分别采用1mm和3mm,注射速率采用4ml/s。采用最大密度和容积重建2种后处理成像方法。根据颈动脉血管边缘的清晰度、光滑度、颈动脉的分级以及对斑块的显示能力由3位高年资放射科医生进行综合评判。结果在血管边缘光滑度方面,3mm层厚组血管边缘多呈锯齿状,1mm层厚组血管边缘多光滑;3ml/s注射速率组血管边缘多毛糙,密度不均,4ml/s组血管边缘光滑。应用容积重建时,在血管边缘光滑度方面,2组不同层厚间、2种不同速率间无明显差异。MIP显示硬斑块引起的狭窄受钙化程度的影响大,VR显示颈动脉狭窄时,受钙化的影响小,多层面容积重建可以直接显示斑块。结论VR受技术因素影响小,显示硬斑块引起的狭窄有优势,但邻近结构可能影响分支血管的观察。
Objective To compare the differences of carotid imaging volume reconstruction and maximum density projection reconstruction in displaying carotid artery lesions by multislice spiral CT. Methods A total of 72 cases of clinical and experimental animals were randomly selected from CT carotid artery imaging. Among them, 30 cases were divided into 2 groups by randomization. The injection rates were 3ml / s and 4ml / Also randomly divided into two groups, the scanning layer thickness were used 1mm and 3mm, injection rate using 4ml / s. Two methods of post-processing imaging using maximum density and volume reconstruction. According to the sharpness and smoothness of the carotid artery margins, grading of the carotid artery and the ability of the plaque to display were comprehensively evaluated by three radiologists with high seniority. Results In the 3 mm / s injection rate group, the margin of the blood vessels in the 3 mm / s group was more rough and the density was not uniform. The margin of the vessel in 4 ml / s group was smooth . When volume reconstruction was used, there was no significant difference in the smoothness of the blood vessels between the two groups of different layer thicknesses. MIP showed that the plaque caused by the hard plaque affected by the degree of calcification, VR showed carotid artery stenosis, affected by calcification is small, multi-level volume reconstruction can directly display the plaque. Conclusion VR is less affected by technical factors and shows the advantage of stenosis caused by a plaque. However, the adjacent structures may affect the observation of branch vessels.