80KV管电压在主动脉CT造影中的应用

发布时间：2018-01-25 07:20

本文关键词： CTA 主动脉低剂量体重指数　出处：《吉林大学》2012年硕士论文　论文类型：学位论文

【摘要】：目的：第一部分：比较120kV自动管电流组、80kV490mAs扫描组，两组之间主动脉CTA图像质量与射线剂量的变化，并比较80kV管电压下不同体重指数的患者CT辐射计量与图像质量的变化，为受检者提供个体化扫描方案。方法：搜集在我院接受256层螺旋CT主动脉造影检查的患者146例，实验分成两部分，第一部分设置管电压为120kV（120kV扫描组）自动管电流，80kV管电压（80kV扫描组）490mAs管电流，第二部分设置特定管电压为80KV，根据体重指数分成3组，A组，体重指数大于25kg/m~2的患者；B组，体重指数在20-25kg/m~2之间；C组，体重指数在20kg/m~2以内。其中A组给予490mAs管电流（490mAs扫描组），B组给予400mAs管电流（400mAs扫描组），C组给予300mAs管电流（300mAs扫描组）。结果： 80kV扫描组主动脉强化值较120kV扫描组主动脉强化值高，但无统计学意义，(372.1±74.7HU vs368.9±78.8HU; P=0.87)。80kV扫描组及120kV扫描组图像SNR分别为（34.3±9.0）和（36.3±9.1），差异无统计学意义(P=0.39)，对比度噪声比分别为（29.0±8.6）和（30.7±8.3），差异无统计学意义(P=0.44）。80kV扫描组和120kV扫描组的有效剂量分别为（9.7±0.8）mSv和（14.3±5.9）mSv，差异有统计学意义(P0.001）。490mAs扫描组、400mAs扫描组及300mAs扫描组信号噪声比(SNR)和对比度噪声比(CNR)，P值分别为0.687和0.749，均无统计学意义。490mAs扫描组ED为（9.939±0.4280）mSv，400mAs扫描组ED为（7.794±0.5765）mSv，300mAs扫描组ED为（5.836±0.3663）mSv，三者有显著性差异（P=0.000）。对三组进行两两比较P值均小于0.05，，均有统计学意义。结论：在CT主动脉造影中，80kV管电压所得到的图像信号噪声比和对比度噪声比及图像质量与120kV管电流相比没有显著变化。80kV管电压在多层螺旋CT主动脉造影中即可得到符合诊断条件的图像质量。在此管电压基础上对于体重指数在20～25kg/m~2之间，应选用400mAs管电流，体重指数小于20kg/m~2应选用300mAs管电流。降低管电流，直接降低了光子能量，但增加了造影剂的CT值。在以后的研究中，我们还可以根据患者的体重指数，在降低辐射剂量的同时，降低造影剂的使用量，既降低了患者的辐射危害又缓解了患者的经济压力。
[Abstract]:Objective: The first part: compare the quality of aortic CTA image and the change of radiation dose between the 120 kV automatic tube current group and the 80kV 490mAs scanning group. The changes of CT radiation measurement and image quality of patients with different body mass index (BMI) under 80 kV tube voltage were compared. Methods: 146 patients underwent 256-slice spiral CT aortic angiography in our hospital were divided into two parts. In the first part, the voltage of the tube was 120 kV / 120 kV) automatic tube current was set. The voltage of 80kV tube was divided into three groups according to body mass index (BMI). The voltage of 80kV scanning group was 490mAs current. The second part was divided into three groups according to body mass index (BMI) with a specific voltage of 80kV. Patients with body mass index greater than 25kg / mm2; In group B, body mass index ranged from 20 to 25 kg / m ~ (2); In group C, body mass index was less than 20 kg 路m ~ (-2). Group A was given 490mAs current current scan group. Group B was given 400mAs current and 400mAs scanning group was given 300mAs current and 300mAs scanning group. Results: The enhancement value of aorta in 80 kV scan group was higher than that in 120 kV scan group, but there was no significant difference between them (372.1 卤74.7 Hu vs368.9 卤78.8 HUU). The SNR of 0.870.80kV scanning group and 120kV scanning group were 34.3 卤9.0) and 36.3 卤9.1) respectively. The contrast noise ratio was 29.0 卤8.6) and 30.7 卤8.3 respectively. There was no significant difference in the effective doses of 0.440.80kV scanning group and 120kV scanning group (9.7 卤0.8mSv and 14.3 卤5.9 mSv, respectively). The difference was statistically significant (P 0.001N. 490mAs scan group, 400mAs scan group and 300mAs scan group, signal noise ratio (SNR) and contrast noise ratio (CNR)). P values were 0.687 and 0.749, respectively. Ed in 490mAs group was 9.939 卤0.4280mSv. Ed of 400mAs scan group was 7.794 卤0.5765mSvA300mAs scan group, Ed was 5.836 卤0.3663mSv. There was significant difference among the three groups (P < 0.05, P < 0.05). Conclusion: In CT aortic angiography. The image signal noise ratio, contrast noise ratio and image quality obtained from 80 kV tube voltage have no significant change compared with 120 kV current. 80 kV tube voltage can be obtained in multislice spiral CT aortic angiography. The image quality was obtained according to the diagnostic conditions. Based on the voltage of the tube, the body mass index was between 20 and 25 kg / mm2. We should choose 400mAs current and 300mAs current when the body mass index is less than 20kgmm2, which reduces the photon energy directly. However, the CT value of contrast agent was increased. In future studies, we can also reduce the dose of contrast agent while reducing the dose of radiation according to the patient's body mass index. Both reduce the patient's radiation hazards and ease the patient's economic pressure.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R816.2

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