摘要
目的比较128层CT低管电压(80 kV)和标准管电压(120 kV)头颈部动脉成像(CTA)的辐射剂量和图像质量,探讨低管电压扫描的可行性。方法 50例行头颈CTA的患者随机分为A(80 kV、175 mAs)、B(120 kV、175 mAs)二组,每组25例。从3个水平测定血管内CT值、噪声(N)、背景信号,计算对比噪声比(CNR)和信噪比(SNR)。2名研究者采用4分法评价图像质量。记录剂量长度乘积(DLP)。对二组间各值的差异进行统计学分析。结果 A组血管CT值高于B组[颈总动脉水平:(568.33±99.16)HU vs(378.45±49.22)HU;颈内动脉水平:(641.33±103.29)HU vs(435.73±59.91)HU;大脑中动脉水平:(549.80±65.08)HU vs(347.92±49.09)HU],差异有统计学意义(P<0.05)。A组N明显高于B组[颈总动脉水平:(10.93±2.18)HU vs(6.48±1.34)HU;颈内动脉水平:(5.29±0.51)HU vs(3.37±0.57)HU;大脑中动脉水平:(8.98±0.94)HU vs(5.76±1.79)HU],差异有统计学意义(P<0.05),但A、B二组SNR、CNR无统计学差异(P﹥0.05)。A、B二组除右锁骨下动脉外,各主要动脉节段影像评分无统计学差异(P﹥0.05)。A组辐射剂量较B组明显降低[DLP:(272.23±36.82)mGy·cm vs(913.40±36.64)mGy·cm],差异有统计学意义(P<0.05)。结论 128层CT低管电压头颈部CTA可以在较低辐射剂量下获得满足诊断要求的图像质量,但是需要降低对比剂用量以减少右锁骨下静脉的硬束伪影。
Objective To evaluate dose performance and image quality of 80 kV in comparison to 120 kV in cerebral and carotid CTA with 128 slice CT and to evaluate the feasibility of low tube voltage. Methods Fifty patients underwent cerebral and carotid CTA were randomly assigned to two different protocols in this trial ： group A （ n = 25 ） examined with 80 kV protocol and group B （n = 25） tested with 120 kV protocol. Objective indices such as vascular attenuation, image noise （N）, signal to noise ratio （SNR） and contrast to noise ratio （CNR） were analyzed. Subjective image quality was assessed by two observers in consensus using a four point scale. Dose length product （DLP） was recorded. Image quality and radia tion dose were compared with t test between the two groups. Results Vessel attenuation was significantly higher in group A than that in group B（ common carotid artery, CCA level： （568.33 ± 99.16）HU vs. （378.45 ± 49.22）HU, P 〈 0.05 ;in ternal carotid artery,ICA level： （641.33 ±103.29） HU vs. （435.73± 59.91 ） HU, P 〈 0.05 ; middle cerebral artery, M level ： （ 549.80±65.08 ） HU vs. （ 347.92 49.09 ） HU, P 〈 0.05 ）. Noise was significantly higher in group A than group B（ CCA level： （10.93 22.18）HUvs. （6.48±1.34）HU, P〈0.05;ICAlevel： （5.29.0.51）HUvs. （3.37±0.57） HU, P 〈 0.05 ; M level ： （ 8.98 ± 0.94） HU vs. （5.76 ± 1.79 ） HU, P 〈 0.05 ）, however, there was no significant differ enee in SNR and CNR（ P 〉 0.05 ）. Subjective image quality was rated similar in both groups except for the fight subclavi an artery （ P 〈 0.05 ）. The effective dose of group A was significantly lower than that of group B [ DLP ： （ 272.23 ± 36.82 ） mGy cm vs. （913.40 ±36.64） mGy cm P 〈 0.05 ]. Conclusion Cerebral and carotid CTA with 80 kV is feasible with diagnostic image quality and significantly reduce radiation dose, but low volume contrast medium should be used to re duce the streak artifacts of the fight
出处
《临床放射学杂志》
CSCD
北大核心
2013年第11期1662-1665,共4页
Journal of Clinical Radiology
