对标准体型病人行低管电压CT肺动脉成像的可行性研究

赵磊杨晓光包丽丽刘挨师

对标准体型病人行低管电压CT肺动脉成像的可行性研究

赵磊1杨晓光1包丽丽2刘挨师1

目的通过对比低管电压CT肺动脉成像（CTPA）与常规CTPA的影像质量与辐射剂量，从而评价低管电压CTPA应用于标准体型病人的临床价值。方法前瞻性选取我院2013年2月—2014年8月标准体型（体质量指数≤25 kg/m2，体质量≤80 kg）病人60例，并随机分为2组。A、B两组管电压分别设置为80 kV和120 kV。管电流设置基于循环时间测试峰值。评价并对比A、B两组影像质量与辐射剂量，选取肺动脉干影像质量参数与辐射剂量进行Pearson相关性分析。结果A组总体肺动脉CT值与噪声值高于B组，差异具有统计学意义（P= 0.000）。A组总体肺动脉SNR和CNR与B组相比差异无统计学意义（分别P=0.187，P=0.309）。A组有效剂量显著低于B组［（1.69±0.43）mSv∶（5.63±1.84）mSv，P=0.000］。有效剂量与CT值和噪声值呈负相关。结论低管电压CTPA应用于标准体型病人可以有效减低辐射剂量，同时保证影像质量，具有临床应用价值。

体层摄影术，X线计算机；血管成像；肺栓塞

DOI：10.19300/j.2016.L3343

【Abstract】ObjebtiveThe purpose of this study was to compare image quality and radiation dose between low voltage CT pulmonary angiography（CTPA）and conventional CTPA protocols in patients of standard body type.Methods60 consecutive patients with low body mass index（≤25 kg/m2）and low body mass（≤80 kg）suspected having pulmonary embolism（PE）were prospectively enrolled from February 2013 to August 2014.The patients were divided into two groups. Tube voltage was set at 80 kV for group A and 120 kV for group B.Tube current settings were determined by testing bolus peak attenuation.Radiation dose and image quality were compared between the two groups.The relationship between image quality parameter and radiation dose measured at pulmonary artery trunk were analyzed with Pearson correlation.Results The total pulmonary arteries showed significantly higher attenuation and noise in group A than in group B（P=0.000）.The total signal-to-noise ratio and total contrast-to-noise ratio did not significantly differ between groups A and B（P=0.187，P= 0.309，respectively）.The mean effective dose showed significantly lower in group A than in group B（1.69±0.43 mSv vs 5.63± 1.84 mSv，P=0.000）.The attenuation or noise and effective dose was negatively correlated.ConclusionUsing 80 kV-CTPA can achieve stable image quality with reduced effective radiation dose compared with 120 kV-CTPA in patients with low body mass index（≤25 kg/m2）and low body mass（≤80 kg）.

【Key words】Tomography，X-ray computed；Angiography；Pulmonary embolism

Int J Med Radiol，2016，39（2）：107-110；115

CT肺血管成像（CT pulmonary angiography，CTPA）是一种对可疑肺栓塞筛查或肺栓塞溶栓后评价的重要诊断工具，已常规应用于临床实践［1］。由于其扫描范围覆盖整个胸部，因而辐射剂量较高［2］。近年来，随着迭代重建算法的投入使用，80～100 kV逐渐开始替代120～140 kV［3-6］。低管电压可以提高靶血管的衰减值，与120 kV相比，80 kV下的X线更易产生光电效应，从而一定程度上提高了影像质量［7］。多项100 kV与80 kV的研究均得出了上述结论［3-6，8］。本研究尝试通过降低管电压来降低辐射剂量，并与常规CTPA方案进行影像质量与辐射剂量的比较，从而明确其临床应用的可行性。……