管电压对下肢CT血管成像辐射剂量及图像质量的影响研究

目的:研究管电压对下肢CT血管成像辐射剂量及图像质量的影响。方法:选取2016年1月-2017年10月于我院行下肢CT血管成像的患者102例,将其以随机数字表法均分成观察组与对照组,每组51例。对照组管电压取120kV,观察组管电压取80kV,其他扫描参数相同。分别比较两组辐射剂量情况、客观图像质量以及主观图像质量情况。结果:观察组CT剂量指数(CTDIvol)、计量长度乘积(DLP)、有效辐射剂量(ED)水平均明显低于对照组,差异均有统计学意义(P0.05)。观察组腹主动脉、髂总动脉、股动脉、腘动脉、胫前动脉、胫后动脉、腓动脉CT值以及图像噪声均明显高于对照组,差异均有统计学意义(P0.05),两组动脉对比噪声比(CNR)和信噪比(SNR)比较差异无统计学意义(P0.05)。观察组血管阶段显示评分、血管细节分支显示评分均明显高于对照组,而血管边缘锐利度评分明显低于对照组,差异均有统计学意义(P0.05)。结论:下肢CT血管成像采用80kV管电压扫描可有效降低患者所接受的辐射剂量,且能获取较为满意的图像,值得临床推广应用。

Effect of Tube Voltage on Radiation Dose and Image Quality of CT Angiography in Lower Extremities

ABSTRACT Objective: To study the effect of tube voltage on radiation dose and image quality of CT angiography in lower extremities. Methods: 102 patients with CT angiography of the lower extremities in our hospital in January 2016 to October 2017 were selected. The patients was divided into the observation group and the control group by the random digital table method, with 51 cases in each group. The control group was given tube voltage with 120 kV, the observation group was given tube voltage with 80 kV, and the other scanning parameters were the same. The radiation dose, the objective image quality and the subjective image quality of the two groups were compared. Results: The computed tomographic dose index (CTDIvol), dose length product (DLP) and effective dose (ED) levels in the observation group were significantly lower than those in the control group, the differences were statistically significant (P<0.05). The CT value of abdominal aorta, iliac artery, femoral artery, popliteal artery, anterior tibial artery, posterior tibial artery, the peroneal artery and image noise in observation group were significantly higher than the control group, the differences were statistically significant(P<0.05). There was no significant difference in contrast noise ratio (CNR) and noise-signal ratio (SNR) between the two groups (P>0.05). The score of vascular phase and the score of vascular detail branch in the observation group were significantly higher than those of the control group, while the vascular edge sharpness score of the observation group was significantly lower than that of the control group, the difference was statistically significant(P<0.05). Conclusion: CT angiography of the lower extremities with 80 kV tube voltage scanning can effectively reduce the radiation dose accepted by the patients, and it can obtain satisfactory images, which is worthy of clinical application.