摘要
目的评价次低剂量胸部CT扫描临床应用价值。方法分为试验阶段和临床观察阶段。试验阶段观察100例,次低剂量法与常规剂量法各观察50例。按体重分为<65kg,65～75kg,>75kg3组。次低剂量法扫描参数为层厚10mm,螺距1.5,管电压120kV,管电流100mA;时间360°/s。常规剂量法除管电流采用160mA外,其余条件同次低剂量法。CT图像分为5个等级评分。将照片上所有扫描条件遮盖,由2位不知道详细资料的影像科医师分别对扫描图像质量作出5个等级评分。在对试验结果初步肯定基础上,对1462例作进一步临床应用观察。结果试验阶段,观察者1和观察者2对<65kg,65～75kg,>75kg两个体重组的评分结果,经统计分析次低剂量法与常规法图像无显著性差别;但常规法得分普遍较次低计量法高。次低剂量法图像的胸壁软组织、纵隔结构以及病灶内部等的噪声较常规法要高,对密度分辨率及均匀性有一定影响,但不影响辨认小的空洞、钙化等异常。用次低剂量法作1462人次胸部扫描,未发现明显影响诊断的病例。结论次低剂量胸部扫描能够取代常规剂量法。
Objective To probe role of lower-dose spiral CT in clinical settings. Methods The study fell into two phases as trial phase and clinical observation phase. The former had 100 cases, with 50 undergoing regular dose and 50 undergoing low-dose. According to body weight, the subjects were classified into three groups as 〈65kg, 65～75kg, and 〉75kg. Parameters for scanning with lower dose were slice thickness 10mm, helical pitch 1.5, tube voltage 120kV, tube current 100mA and time 360°/s. As for regular dose, parameters were the same with the low-dose group except for a tube current at 160mA. CT findings were scored 5 ranks by two radiologists who did not know classification of either cases or imaging methods. After having confirmed preceding results, further observation of 1462 cases. Results During trical phase, the two radiologists did not find obvious differences in imaging findings between the two doses in two body weight groups （〈65kg, 65～75kg, 〉75kg）. However,scores for regular dose were universally higher than that for lower dose. Imaging findings of lower-dose had a higher intensity for soft tissues of chest wall, mediastinum and noise inside the lesions, taking negative effects on determination of density and evenness however it was effective in identifying small caves and calcifications. Further scanning of chests of 1462 people with lower dose did not indicate that it obviously undermine correctness. Conclusion Lower-dose CT is able to replace regular dose one in imaging of chest.
出处
《中国CT和MRI杂志》
2006年第2期26-27,30,共3页
Chinese Journal of CT and MRI
