16层螺旋CT肺支气管低电压扫描图像质量评估

目的 探讨16层螺旋CT肺支气管低电压扫描中具有实用价值的技术参数.方法 采用西门子16层螺旋CT机,对120例中等体型具有肺部疾病的患者分组进行肺部不同电压CT扫描,电压分别设为80kV、100kV、120kV,Ⅰ组为固定100mA组,Ⅱ组以不同电压扫描的同时启用自动管电流调制技术,参考管电流分别提高到为180mAs、130mAs、100mAs,其他参数均相同,在工作站对各组图像质量评分后作统计学对比分析.结果 各组对支气管级别、最小支气管管径显示、支气管边界清晰度及密度分辨力均未见明显差别;80kV组噪声略高于其他两组,100kV组与120kV组噪声未见显著性差异,而CTDI其中80kV组较120kV组降低了65.53％,100kV组较120kV组降低了33.08％,剂量补偿后图像噪声略有改善.结论 与常规管电压120 kV扫描方案相比,采用低管电压80 kV及100 kV,适当给予管电流补偿,可以在保证图像质量的同时,有效降低辐射剂量,在多层螺旋CT肺支气管成像中具有较高的临床应用价值.

Image quality evaluation of low tube voltage 16-slice MSCT in pulmonary bronchus scaning

Objective To investigate the technical parameters with practical value of low tube voltage 16-slice spiral CT in pulmonary bronchus scaning. Methods Simens 16-slice CT machine was used in 120 medium size patients＇ chest sca- ning. Patients were divided into six groups with different tube voltages. With the same tube current （100 mAs）, the first three groups are scaned using 80 kV, 100 kV and 120 kV tube voltages respectively. The second three groups are examed not only with different tube voltages but also with care dose technique. Images quality score of each group were made sepa- rately after statistically analyzed in workstation. Results There is no significant differences in bronchus classification, trail of bronchus, bronchus boundary definition and density resolution. Noise in 80 kV group is higher than other two groups slightly. The radiation dose of 80 kV decreases by 65.53% compared with the 120 kV group,group 100 kV is 33. 08% lower than 120 kV group. Conclusion The application of 80 kV and 100 kV protocol combined with automatic tube current modulation scanning in 16-slice MSCT pulmonary bronchus examination could significantly reduce radiation dose compared with the conventional 120 kV protocol without deterioration in diagnostic image quality.