低剂量与常规剂量对比剂双能量肺灌注图像质量对比分析

Comparative analysis between low-dose and conventional-dose contrast medium of dual energy lung perfusion imaging

目的:探讨对比剂剂量对双源CT双能量肺灌注成像质量的影响。方法:疑肺动脉栓塞患者行双源CT双能量肺灌注扫描,30例使用低剂量(0.7ml/kg)对比剂,30例使用常规剂量对比剂(1.5ml/kg),注射速率均为4.5ml/s。扫描后同时获得肺动脉CTA及肺灌注图像。测量左、右叶肺动脉干及各肺叶动脉增强后的CT值,对比分析两组间增强后的CT值。判断肺灌注图像质量并分级,比较两组的肺灌注图像质量差异。结果:低剂量组与常规剂量组左、右叶肺动脉干及各肺叶动脉增强后的CT值无明显差异(P>0.05)。肺段及亚段肺动脉图像清晰显示。低剂量组肺灌注图像大部分信号均匀(26/30),常规剂量组肺灌注图像大部分信号均匀(24/30)。常规剂量组上腔静脉、右心房高密度对比剂所致灌注伪影明显多于低剂量组(48:10)。结论:低剂量与常规剂量双能量肺灌注成像的肺动脉图像质量无明显差异,降低对比剂剂量可以减少双能量肺灌注图像的伪影。

Objective：To investigate the effects of low-dose contrast medium on image quality of dual source CT dual energy lung perfusion imaging（DEPI）.Methods：Thirty consecutive patients with suspected pulmonary embolism（PE） underwent dual source CT perfusion imaging with low-dose（0.7 ml/kg） contrast medium,another 30 patients with conventional doses of contrast medium（1.5 ml /kg）.CT pulmonary angiography（CTPA） and lung perfusion images were acquired at the same time.Injection rates of two groups were 4.5 ml /s.The enhanced CT values of pulmonary artery were measured.The quality and grade of lung perfusion image were determined and comparative analysis was performed between the two groups.Results：There was no significant difference between low-dose group and the conventional dose group in enhanced CT value of pulmonary artery（P0.05）.Segment and sub segmental pulmonary were clearly showed.The lung perfusion images were homogeneous signal in majority cases of low-dose group（26/30）,but the majority of conventional-dose group were heterogeneous signal（24/30）.Conventional-dose group was significantly higher than low-dose group in artifacts due to the high density of contrast medium of superior vena cava and right atrium（48：10）.Conclusion：There was no significant difference between low-dose and conventional-dose DEPI in image quality and reduced dose of contrast medium can reduce the artifacts of DEPI.