目的：分析采用低剂量CT（low-dose CT，LDCT）在无症状体检者中进行肺癌筛查的结果。方法：2015年4月至2018年4月共有22 351例无症状体检者（16~95）岁接受肺LDCT检查，根据结节有无及大小、类型分成阳性结节、半阳性结节、阴性结节组，分析不同年龄段、性别体检者LDCT肺结节和肺癌筛查结果，并分析不同类型结节在阳性、半阳性结节中的检出情况，记录随访复查过程中结节的变化。结果：肺结节总检出率为31%，男性及女性的结节检出率分别为34.1%、28.8%，差异有统计学意义（ χ²=70.47，P<0.001）。不同年龄段人群的结节检出率也不同，差异有统计学意义（ χ²=1032.96，P<0.001），年龄越大，结节检出率越高，81~95岁人群的结节检出率（50.0%）最高。不同性别间的阳性结节检出率不同，差异有统计学意义（ χ²=184.36，P<0.001），男性群体的阳性结节检出率（10.1%）高于女性群体（8.6%）。不同年龄段的阳性结节检出率不同，年龄越大，阳性结节检出率越高，差异有统计学意义（ χ²=434.89，P<0.001）。22 351例无症状体检者的总体肺癌检出率为0.4%。以手术病理为对照，基线筛查检出肺癌48例;35个月随访期内，经复查后检出肺癌47例。男性和女性的肺癌检出率分别约为0.6%和0.3%，不同性别间的肺癌检出率差异有统计学意义（ χ²=7.52，P=0.006）;50岁以上人群的肺癌检出率明显高于50岁以下者（0.7%比0.1%），差异有统计学意义（ χ²=42.20，P<0.001）。阳性结节组和半阳性结节组的肺癌检出率分别为4.5%和0.1%，差异有统计学意义（ χ²=207.78，P<0.001）。阳性与半阳结节在不同密度类型结节中的构成比不同（ χ²=267.06，P<0.001）。不同密度类型结节中恶性结节检出率不同，差异有统计学意义（ χ²=131.77，P<0.001），且部分实性结节中恶性结节检出率高，达4.3%。随访期内，接受了年度复查或双年度复查的4 557例半阳性结节受检者，仅2例受检者经病理证实为早期肺癌。总的检出结节中恶性结节占比0.7%。结论：采用LDCT进行肺癌筛查对中老年人群十分重要，尤其是50岁以上人群。对于半阳性结节，年度复查是可行的;对于筛查出的肺结节，总体恶性结节的占比（0.7%）仍较低，应结合结节大小、类型和形态学特征等，制定合理的随访处理方案。

Objective: To analyze the results of low-dose CT(LDCT) screening for lung cancer in asymptomatic patients. Methods: From April 2015 to April 2018, 22 351 asymptomatic patients(16—95 years old) underwent lung LDCT examination. According to the size and type of nodules, they were divided into positive nodules, semi-positive nodules and negative nodules. The results of LDCT lung nodule detection and lung cancer screening in different age groups and gender groups were analyzed. Detection of different types of nodule in positive and semi-positive nodules was analyzed too. The changes of nodule during follow-up were recorded. Results: The total detection rate of pulmonary nodule was 31%. The detection rates in male and female were 34.1% and 28.8%, respectively; the difference was significant ( χ²=70.47, P<0.001). The detection rate of nodule was different in different age groups, and the difference was statistically significant ( χ²=1 032.96, P<0.001). The older the age group, the higher the detection rate of nodule. The detection rate of nodule in 81—95 age group was the highest (50.0%). The detection rate of positive nodules was different in different genders, the difference was statistically significant ( χ²=184.36, P<0.001). The detection rate of positive nodules in male population (10.1%) was higher than that in female group (8.6%). The detection rate of positive nodules was different in different age groups, and the difference was statistically significant ( χ²= 434.89, P<0.001). The overall detection rate of lung cancer was 0.4%. Forty-eight cases of lung cancer were detected by baseline screening, and 47 cases of lung cancer were detected by follow-up within 36 months. There was a significant difference in detection rate of lung cancer between different genders ( χ²=7.52, P=0.006). The detection rate of lung cancer in male and female was about 0.6% and 0.3%, respectively. The detection rate of lung cancer in patients over 50 years old was significantly higher than those under 50 years old, and the detection rate was about 0.7% and 0.1%, respectively. The difference was statistically significant ( χ²=42.20, P=0.006). P<0.001). The detection rates of lung cancer in positive and semi-positive nodule groups were 4.5% and 0.1%, respectively. The difference was statistically significant ( χ²=207.78, P<0.001). The proportion of positive and semi-positive nodule in nodules of different density types was different ( χ²=267.06, P<0.001). The detection rate of malignant nodule in different density types was different, the difference was statistically significant ( χ²=131.77, P<0.001). The detection rate of malignant nodule in part-solid nodules was high, up to 4.3%. During the follow-up period, 4 557 patients with semi-positive nodules underwent annual review or biennial review, and only 2 patients were pathologically confirmed as early lung cancer. Malignant nodules accounted for 0.7% of the detected nodules.Conclusions: LDCT lung cancer screening is very important for middle-aged and elderly people, especially those over 50 years old. For semi-positive nodules, annual review is feasible. For the screened pulmonary nodules, the overall proportion of malignant nodules (0.7%) is low. A reasonable follow-up management plan should be formulated according to the size, type and morphological characteristics of nodules.