双低剂量对比剂和最佳单能谱成像在头颈部CTA中的应用价值

摘要

Objective To evaluate the feasibility of adopting low-dose contrast agent and optimal gemstone spectral imaging to perform head and neck CTA (Computerized Tomography Angiography). Methods Altogether 60 patients who accepted head and neck CTA were divided into General-Dose Group and Low-Dose Group randomly and evenly with 30 cases in each group. General-Dose Group were given 0.7 mL/kg contrast agent with the lfow rate of 5.0 mL/s;Low-Dose Group were given 0.5 mL/kg contrast agent with the lfow rate of 3.0 mL/s. The remaining scanning parameters of the two groups were similar. The images were reconstructed and the data were sent to the working station for analysis. Then, optimal gemstone spectral images were reconstructed. The CT value and noise of artery on aortic arch, bifurcation of both sides of common carotid arteries and both sides of middle cerebral artery were measured. Then, the statistic differences between the two groups were compared according to the measured values. Results As was shown in 55 keV reconstructed image, there was no significant difference between the CT value and noise of artery on aortic arch, bifurcation of both sides of common carotid arteries and both sides of middle cerebral artery in Low-Dose Group. Conclusion Dual-energy CTA of dual-source CT on head and neck, which adopted 30mL contrast agent to reconstruct optimal gemstone spectral 60±5 keV image, could improve CT value and image noise. It met the standard of imaging diagnosis and clinical requirements. Meanwhile, it reduced about 40%of contrast agent comparing with General-Dose Group, which would reduce the risks of cardiac-cerebral vascular diseases, contrast-induced nephropathy and other side effects caused by contrast agent.%目的：评估采用低对比剂用量和最佳单能谱成像进行头颈部双能量CTA的可行性。方法将60例行头颈部双能量CTA的患者随机分为两组，常规剂组30例行0.7 mL/kg对比剂，流率5.0 mL/s,低剂量组30例行0.5 mL/kg对比剂，流率3.0 mL/s。两组其余扫描参数一致。扫描后重建图像并将数据传到工作站进行分析，进行最佳单能量重建图像。分别测量两组主动脉弓，两侧颈总动脉分叉处，双侧大脑中动脉3个层面动脉血管的强化CT值和图像噪声，并比较两组间的统计差异性。结果在55 keV重建图像中，低剂量组重建图像在主动脉弓层面，双侧颈总动脉分叉层面，大脑中动脉层面，强化CT值，对比噪声均无显著性差异。结论双源CT头颈部双能量血管成像，采用30 mL在对比剂并重建最佳单能量60±5 keV图像，其强化CT值，图像噪声都已达到影像诊断标准，可以满足临床要求，比常规扫描对比剂用量减少近40%，降低了患者发生心脑血管系统相关副作用和对比剂肾病的风险。