双低剂量在头颈部无迭代技术多层螺旋CT血管成像中的可行性

Feasibility of Double Low Dose Technology in Multi-slice Head and Neck CT Angiography Without Adaptive Statistical Iterative Reconstruction

目的通过探讨双低剂量在头颈部无迭代技术多层螺旋CT血管成像（CTA）应用中的可行性,实现在降低辐射剂量的基础上减少对比剂使用量,以降低受检者辐射危害和对比剂肾病发病率。资料与方法选取51例行双低剂量头颈CTA检查的患者作为双低组[管电压100 kV,管电流300 m A,对比剂0.7 ml/kg碘佛醇（320mg I/ml）],51例行常规剂量头颈CTA检查的患者作为常规组[管电压120 kV,管电流350 m A,对比剂1.0 ml/kg碘佛醇（320 mg I/ml）]。测量两组患者血管内CT值和背景噪声,比较两组患者信噪比（SNR）、对比噪声比（CNR）、图像质量主观评分、辐射剂量及碘负荷量。结果双低组与常规组容积CT剂量指数分别为18.00 m Gy、33.86 m Gy,有效剂量分别为3.85 m Sv/（m Gy·cm）、7.25 m Sv/（m Gy·cm）,碘负荷量分别为224 mg I/kg、320 mg I/kg。双低组主动脉弓SNR及CNR高于常规组,但差异无统计学意义（t=-1.572、-1.783,P〉0.05）;双侧颈总动脉、颈内动脉、大脑中动脉SNR及CNR均低于常规组,但差异无统计学意义（t=0.341-1.739,P〉0.05）。双低组及常规组图像质量主观评分分别为（3.69±0.47）分、（3.70±0.46）分,差异无统计学意义（Z=-0.213,P〉0.05）。结论采用双低剂量扫描技术在无迭代技术螺旋CT行头颈部CTA检查可以获得质量满意的图像。

Purpose To explore the feasibility of double low dose technology in multi- slice head and neck CT angiography, so to reduce contrast agent as well as reduce radiation dose. In that way, the hazards of radiation and the risk of contrast induced nephropathy would be reduced. Materials and Methods Fifty-one patients took double low proposal were recruited as double low group. Another 51 patients who took conventional proposal were recruited as conventional group. The scanning parameters of double low group were 100 kV, 300 mA, 0.7 ml/kg iodinated contrast agent and which of conventional group were 120 kV, 350 mA, 1.0 ml/kg iodinated contrast agent. The CT value of the vessels and image noise were measured. Signal-to-noise ratio （SNR）. contrast-to-noise ratio （CNR）, subjective image quality score, radiation dose and iodine load between the two groups were compared. Results The volume CT dose index （CTDIvol） of the double low group and the conventional group were 18.00 mGy and 33.86 mGy, respectively. And the effective dose were 3.85 mSv/（mGy - cm） and 7.25 mSv/（mGy, cm）, respectively. The iodine loads were 224 mgl/kg and 320 mgl/kg, respectively. SNR and CNR at the aortic arch were higher in double low group than in conventional group, but which was not statistic significant （t=-1.572 and -1.783, P〉0.05）. The SNR and CNR of bilateral carotid arteries, internal carotid arteries, and rniddle cerebral arteries had no statistic significance between the two groups （t=0.341-1.739,P〉0.05）. The subjective image quality scores of double low group and conventional group were （3.69±0.47） scores and （3.70±0.46） scores, which showed no statistic difference （Z= - 0.213, P〉0.05）. Conclusion Approving images of multislice head and neck CT angiography can be obtained by using double low dose technology without adaptive statistical iterative reconstruction.