双低剂量CTA评估颅内动脉粥样斑块稳定性的可行性研究

目的探讨双低剂量CT血管成像(CTA)评估颅内动脉粥样斑块稳定性的可行性。方法选取2015年1月—2016年3月期间于神经内科住院的表现有缺血性脑卒中(CIS)症状的病人42例,其中男29例,女13例,平均年龄(62.3±7.69)岁。将病人随机分为双低剂量组和常规剂量组,每组21例。两组管电压、碘对比剂剂量分别为80 k V、50 m L和120 k V、100 m L。对2组病人分别进行CTA检查,并进行相应后处理以显示颅内动脉斑块。采用t检验对比分析2组影像噪声、血管强化程度、影像质量评分及X线辐射剂量的差异,采用χ~2检验比较2组间斑块检出率的差异。结果双低剂量组的噪声显著高于常规剂量组(P0.05),两组间CNR及SNR差异均无统计学意义(均P0.05)。低管电压组大脑中动脉M1段及椎基底动脉监测点的CT值均高于常规管电压组(均P0.05)。双低剂量组和常规剂量组的影像质量评分均显示良好(均2分),两组间各种影像质量评分差异均无统计学意义(P0.05)。两组斑块检出率差异无统计学意义(P0.05)。双低剂量组的CT容积剂量指数、剂量长度乘积和有效辐射剂量均低于常规剂量组(均P0.05)。结论双低剂量组CTA检查能清楚显示颅内动脉粥样斑块形态及成分,可对其稳定性做出较精确的判断,并能有效降低X线对人体的电离辐射剂量及碘对比剂的肾毒性。双低剂量CTA评估颅内动脉粥样斑块稳定性可行,具有临床应用价值。

Stability of intracranial artery atheromatous plaque:evalution using double low doses CTA

Objective To explore the feasibility of dual low-dose CT angiography (CTA) to assess plaque stability. Methods Forty-two cases (male n=29, female n=13;age 62.3±7.69 years) who suffered from cerebral ischemic stroke in our Department of Neurology during January 2015 to March 2016 were recruited. They were randomly divided into two groups, dual low-dose group and the conventional dose group, 21 cases in each group. Each group of patients received CTA with tube voltage and iodinated contrast agent dose 80 kV and 50 mL in dual low-dose group, and 120 kV and 100 mL in conventional dose group. Post processing of intracranial arterial plaque was conducted. The t-test was used to compare the image quality, degree of vascular enhancement, and X-ray radiation dose between the two groups. Chi-square test was used to compare the difference in plaque detection rate between the two groups. Results The standard deviation was significantly higher in dual low-dose group than in the conventional dose group (P<0.05). The contrast noise ratio and signal noise ratio did not significantly differ between the two groups(P>0.05). The dual low-dose group had higher CT values at middle cerebral artery M1 segment and vertebral basilar artery than that of conventional tube voltage group (all P<0.05). The image quality showed good in both groups (>2 points) and did not significantly differ from each other (P>0.05). The plaque detection rates had no statistical significance between the two groups (P>0.05). The CT dose index volume, dose length product, and effective dose in the dual low-dose group were lower than in the conventional dose group (all P<0.05). Conclusions CTA with dual low-dose technique can clearly demonstrate morphology and composition of intracranial arterial plaque, can lead to relatively accurate judgments on plaque stability, and can effectively reduce doses of ionizing radiation and nephrotoxic iodine contrast agent. Therefore, dual low-dose CTA assessment of intracranial arterial plaque stability is feasible and worthy of promotion and has clinical application value.