低剂量螺旋CT筛选检查早期肺癌的初步研究

目的 评价低剂量螺旋CT筛选检查（简称筛检）对肺癌高危险人群早期肺癌的检出率。方法 对无症状300例体检者胸片及CT进行前瞻性研究，纳入标准为年龄45岁以上，吸烟10年包（10年以上，每日1包）以上，或既往有慢性阻塞性肺疾病病史，以前无癌症史，身体状况适合手术治疗者，低剂量CT扫描采用Philip SR 7000及GE LightSpeed Plus多层面CT扫描机。图像由2位放射医师在工作站显示器上以电影显示方式观察，存储至影像存储与传输系统（PACS）。结果 低剂量CT共检出56例（19％）非钙化结节（其中恶性4例），胸片检出9例（3％）（其中恶性3例），均为1期病变。低剂量CT检出叶支气管或段支气管病变9例（3％），其中早期中央型肺癌例（1％），胸片均未检出，胸片、CT对肺癌筛检的敏感度分别为43％、100％，特异度分别为89％、80％。结论 初步筛检结果表明低剂量螺旋CT明显提高了对肺内非钙化小结节及支气管细微病变的检出，可检出早期肺癌。

Early lung cancer baseline screening: preliminary study with low-dose spiral CT

Objective To evaluate the prevalence rate of pulmonary malignant disease detected by low dose spiral CT in people at high risk of lung cancer. Methods Low dose spiral CT scans and chest radiographs in 300 symptom free volunteers from an on going screening study were prospectively evaluated. The study has enrolled 240 smokers, aged 45 years or older, with at least 10 pack years of cigarette smoking and 60 individuals with chronic obstructive pulmonary disease, and without previous cancer history, who were medically fit to undergo thoracic surgery. Low dose CT scans were performed with SR 7000 scanner using spiral mode, 120 kV, 50 mA, pitch 2, 5mm thickness reconstruction and Lightspeed Plus multi slice scanner using spiral mode, 120 kV, 50 mA, pitch 6 to produce 2.5 mm thick image at 2.5 mm increments. All images were assessed with cine display mode on workstation monitor. Results Non calcified nodules were detected in 56 (19%) participants by low dose CT, compared with 9 (3%) by chest radiography. Malignant disease was detected in 4 (1.3%) by CT and 3 (1%) by chest radiography. All 4 cancers were stage I. Lobar or segmental bronchial abnormalities were detected in 9 (3%) participants by CT. Among them, 3 (1%) proved to be early central lung cancer. No bronchial abnormality was detected by chest radiography. The sensitivity and specificity of cancer screening was 43% and 89%, respectively for chest radiograph, 100% and 80%, respectively for CT. The sensitivity of CT was significantly higher than that of radiograph, whereas the specificity showed no statistical difference. Conclusion Preliminary screening study indicates that low dose CT can greatly improve the likelihood of detection for small non calcified nodules and mild bronchial abnormalities, and thus of peripheral and central lung cancer at an earlier stage.