下肢动脉CTA能谱成像的扫描剂量及成像质量研究

Study on scanning dose and imaging quality of gemstone spectrum imaging during lower extremity arterial CTA

目的 :通过下肢动脉CT血管造影(CT angiography,CTA)应用能谱成像(gemstone spectrumimaging,GSI)与自动毫安进行对比研究,探讨GSI是否能降低X线辐射剂量和提高影像质量。方法:选取30名患者分为GSI组和自动毫安组,每组15名。30名患者均行双下肢动脉CTA,自动毫安组使用噪声指数(noise index,NI)为15.48的自动毫安,mA范围20~400 mA;GSI组使用扫描协议GSI-36,260 mA。扫描后记录容积CT剂量指数(CT dose index volumes,CTDIvol和剂量长度乘积(dose length product,DLP),计算有效剂量(effect dose,ED),评价2组影像质量并进行统计学分析。结果:CTDIvol:GSI组为(10.30±0.00)mGy,自动毫安组为(9.72±2.86)mGy;DLP:GSI组为(1 206.31±338.6)mGy·cm,自动毫安组为(1 101.4±375.5)mGy·cm;ED:GSI组为(18.10±5.08)mSv,自动毫安组为(16.52±5.63)mSv;GSI组与自动毫安组的影像质量评分分别为(2.87±0.30)和(2.57±0.46)分,P<0.05,2组差异有统计学意义。结论:下肢动脉CTA应用GSI不能降低X线辐射剂量,但可提高影像质量。

Objective To compare gemstone spectrum imaging（GSI） and auto m A technology for lower extremity arterial CTA to determine whether GSI can decrease radiation dose while increase image quality. Methods Thirty patients were equally divided into a GIS group and an auto mA group. All the patients underwent arterial CTA of both lower limbs. The auto m A group had the noise index（NI） being 15.48 and the current strength range from 20 to 400 mA, and the GSI group applied scanning protocol GSI-36 and 260 mA when used for arterial CTA. The values of CT dose index volumes（CTDIvol） and dose length product（DLP） were recorded, and the effect doses（ED） were calculated. The image quality was evaluated in the two groups, and statistical analysis was carried out. Results GSI and auto m A groups had CTDIvolvalues being（10.30±0.00） and（9.72±2.86） mGy, DLP values being（1 206.31±338.6） and（1 101.4±375.5） mGy·cm, and ED values being（18.10±5.08） and（16.52±5.63） mSv, respectively. The image quality score was（2.87±0.30） in GSI group and（2.57±0.46） in auto mA group,and there were significant difference between the scores（P 0.05）. Conclusion GSI cannot decrease X-ray radiation dose while increase image quality during lower extremity arterial CTA.