能谱CT高清共轭采集技术在血管CTA中的应用价值

摘要

目的:研究宝石能谱CT采用64排128层高清共轭采集技术提高CTA图像空间分辨率,显示微小病变及细微组织结构的能力.方法:选择性选取在我院行不同部位血管CTA检查的患者200例,随机分成两组,各100例.A组,采用128层40mm的高清容积数据采集.B组,采用64层40mm的标准容积数据采集.其他扫描参数不变.由两名影像诊断医师以双盲法对两组图像质量进行评分,并记录MRP、CPR图像上血管腔内和周围软组织的图像噪声值、辐射剂量值(ED),计算均值及标准差并进行统计学分析.结果:①两组图像质量评分分别为3.52±0.48和3.12±0.56,差异有统计学意义(t=7.14,P＜0.05),A组图像对细微结构及微小病变的显示明显优于B组.②两组图像血管腔内和软组织的图像噪声值分别为14.06±1.03和13.43±0.97、24.26±1.79和23.79±1.61,组间差异无统计学意义(P均＞0.05).③两组图像的ED值分别是4.02±0.58mSv和3.59±0.10mSv,差异有统计学意义(t=6.18,P＜0.05).结论:在CT血管成像中,使用高清共轭采集技术,有效地降低辐射剂量,同时极大地提高图像的空间分辨率,得到优质的三维重组图像,清晰地显示血管内软硬斑块及支架内部情况,更有助于微小病变的显示,放大后依然可以满足诊断要求.%Purpose: To study the high definition (HD) conjugate acquisition technology on 64 rows and 128 slices GEM spectrum CT to improve the spatial resolution of CTA image, and to improve the display rate of small lesions and subtle structures. Methods: Two hundreds cases which had undergone CTA in our hospital were consecutively selected. These cases were divided into two groups randomly, and with 100 cases each. The cases of group A were scanned with 128 slices of 40mm HD volume data acquisition. The cases of group B were scanned with 64 slices of 40mm standard volume data acquisition. Other scan parameters for the two groups were the same. The image quality of the two groups images were rated by two radiologists in a double-blind way. The noise value for endovascular and surrounding soft tissue on the MPR and CPR images and effective dose were recorded. The mean and standard deviation of them were calculated, and statistical analysis was made. Results: (1) The image quality score for the two groups were 3.52±0.48 and 3.12±0.56, the discrepancy had statistical significance (t=7.14, F<0.05). The images of group A showed the fine structure and minimal change significantly better than that of group B. (2) The noise value of lumen and soft tissue in group A were 14.06±1.03 and 13.43±0.97, 24.26±1.79 and 23.79±1.61. No significant difference was shown between the groups (average P>0.05). (3) ED values for the two groups of images were 4.02 + 0.58 and 3.59±0.10mSv. The discrepancy had statistical significance (?=6.18, P<0.05). Conclusion: In CT vascular imaging, by using HD conjugate acquisition technology, the radiation dose can be effectively reduced and the image spatial resolution can be greatly improved, high quality 3D reconstruction imagesrncan be got, soft and hard plaque and intravascular stent can be clearly displayed, more small lesions can be shown.