宝石能谱CT与常规CT在颌面部检查中辐射剂量及图像质量的对比研究

Gemstone Spectral CT Imaging in the Maxillofacial Examination:Initial Results of Radiation Exposure and Image Quality Compared with Conventional CT

目的探讨宝石能谱CT扫描在颌面部检查中对辐射剂量及图像质量的影响。方法收集颌面部CT平扫患者40名,分成两组(A组+B组),每组20名。A组采用单源瞬时kVp切换能谱CT扫描模式,管电压140、80 kVp瞬时(0.5 ms)切换,重建出单能量70 keV水平图像。B组行常规扫描,管电压120 kVp。两组其他扫描参数相同。对两组图像的信噪比、图像显示质量及辐射剂量进行对比。结果A组和B组间脂肪、气体、腮腺和髁突间的信噪比差异无统计学意义(-15.02±5.130和-15.22±6.105,P=0.867>0.05;-151.71±41.103和-169.77±73.295,P=0.179>0.05;0.39±2.821和1.22±3.694,P=0.263>0.05;11.07±5.652和11.56±5.873,P=0.701>0.05),而咬肌、颌下腺和玻璃体的信噪比差异有统计学意义(8.58±2.637和12.31±3.763,P<0.001;7.17±2.407和10.24±5.147,P=0.001;0.97±0.511和2.91±0.867,P<0.001)。主观评价两组图像质量无统计学差异。A组和B组有效剂量分别为:2.80±0.432 mSv,3.54±0.737 mSv(P=0.001)。结论宝石能谱CT扫描在不影响图像质量和影像诊断的前提下,与常规扫描相比,能有效降低辐射剂量。

Objective To explore the effect of gemstone spectral CT scanning on radiation exposure and image quality in maxillofacial examination.Methods Forty patients with maxillofacial CT plain scan were divided into two groups(A group and B group).Each gourp included 20 patients.In A group,the gemstone spectral imaging(GSI)with single source instantaneous switch of kVp(140 kVp,80 kVp)on 0.5 ms was performed.And single energy 70 keV level image was reconstructed.In B group,the conventional polychromatic imaging(CPI)with the tube voltage 120 kVp was performed.The other scanning parameters of two groups were the same.The signal-to-noise ratio(SNR),image display quality and radiation dose were compared between the two groups.Results There was no significant difference in SNR of fat,gas,parotid gland and condyle between A group and B group(-15.02±5.130 and-15.22±6.105,P=0.867;-151.71±41.103 and-169.77±73.295,P=0.179;0.39±2.821 and 1.22±3.694,P=0.263;11.07±5.652 and 11.56±5.873,P=0.701).There was significant difference in the SNR of masseter,submandibular gland and vitreum between A group and B group(8.58±2.637 and 12.31±3.763,P<0.001;7.17±2.407 and 10.24±5.147,P=0.001;0.97±0.511 and 2.91±0.867,P<0.001).There was no statistical difference in subjective evaluation between two groups.And ED of A group and B group were 2.80±0.432 mSv and 3.54±0.737 mSv(P=0.001).Conclusion GSI can effectively reduce radiation dose compared with CPI without affecting image quality and clinical image diagnosis.