双源光子CT低管电压联合低剂量对比剂在颅内动脉瘤患者血管成像中的临床应用价值

Application of low volum contrast medium protocol on dual-source photons CT low tube voltage in patients with intracranial aneurysms

目的探讨双源光子CT低管电压(80kV)低剂量对比剂(30ml)技术("双低"技术)在颅脑CTA颅内动脉瘤检出中的临床应用价值。方法 50例疑有颅内动脉瘤患者行颅脑CTA检查,随机分为两组(每组25例):甲组采用管电压120kV、对比剂50ml;乙组采用管电压80kV、对比剂30ml。测量颈内动脉海绵窦段及大脑中动脉M1段的CT值、噪声、信噪比(SNR)及对比信噪比(CNR),并对图像质量进行主观评价。以DSA结果为金标准,比较两组图像检出动脉瘤的特异度及灵敏度。结果乙组颈内动脉海绵窦段及大脑中动脉M1段CT值高于甲组(P <0. 001),SNR、CNR低于甲组(P <0. 05),两组图像质量主观评价(P=0. 295)、诊断动脉瘤的特异度、灵敏度(P> 0. 05)差异无统计学意义。乙组有效辐射剂量较甲组下降约52%。结论双源光子CT"双低"技术不仅满足颅脑CTA对颅内动脉瘤的检出,并且明显降低了辐射剂量与对比剂用量。

Objective To investigate the application value of the stellar CT with a low-tube-voltage combined with a low-dose contrast medium in detecting the intracranial aneurysms. Methods Fifty patients of suspecting intracranial aneurysms were divided randomly into 2 groups： Group A, tube voltage （120 kV） and contrast medium （50 ml） ; Group B, tube voltage （80 kV） and contrast medium （30 ml）. The following data, including CT value, image noise, signal-to-noise ratios （SNR） and contrast to-noise ratio （CNR） of the cavernous segment of the internal carotid artery and the M1 segment of the nfiddle cerebral artery, were also analyzed between the two groups. The subjective image quality was also evaluated. Taking the result of DSA as the reference standard, the specificity and sensitivity of the two groups in detecting the aneury-sm were compared. Results The CT value of the cavernous segment of the internal carotid artery and the M1 segment of the middle cerebral artery, in Group B was higher than the Group As＇ （ P 〈 0.001 ）, and the SNR and CNR of Group B was lower than the Group As＇ （ both P 〈 0.05 ）. There was no significant difference among the sensitivity, specificity of intracranial aneurysms and the subjective evaluation of image quality between the two groups. The radiation dose of Group B was 52%, lower than Group A. Conclusion ＂Double low＇stellar CTA technique not only meets the detection of aneurysms, but also greatly reduces the radiation dose and the contrast agent dose.