CT在涂阴继发性肺结核中的诊断价值

目的探讨CT对涂阴继发性肺结核的诊断价值。方法收集118例涂片阴性的肺结核可疑者,同时行X线胸片和CT检查,其中肺结核76例,非结核性肺病42例。采用盲法由诊断小组分别对X线胸片和CT进行阅读。采用受试者工作特征曲线(ROC曲线)评价两种诊断手段的优劣。结果按“可能性大”为诊断界点进行统计,则X线胸片诊断的敏感度为81.6%,特异度为61.9%,准确性为74.6%,阳性预计值(PV₊)为76.3%:阴性预计值(PV_-)为69.2%;CT诊断的敏感度为93.4%,特异度为88.1%,准确性为91.5%。阳性预计值(PV₊)为92.2%:阴性预计值(PV_-)为89.8%。X线胸片诊断的ROC曲线下面积(A_z)为(0.758±0.102),CT诊断的曲线下面积(A_z)为(0.958±0.043),X线胸片联合结核抗体、PPD进行诊断的ROC曲线下面积(A_z)为(0.833±0.071)。X线胸片与X线胸片联合诊断的曲线下面积比较有显著性差异,(P<0.05)。但均显著小于CT诊断的曲线下面积,(P<0.05)。结论CT在诊断涂阴肺结核诊断和鉴别诊断方面具有较高的应用价值。

Comparing analysis between chest X-ray film and CT scan in the diagnosis of smear negative pulmonary tuberculosis

Objective To explore the value of CT in diagnosis of secondary smear negative pulmonary tuberculosis compared with chest X-ray film. Methods 118 smear negative pulmonary tuberculosis suspects were detected by chest X-ray film and CT scan,which included 76 cases of pulmonary tuberculosis and 42 cases of non-pulmonary tuberculosis.X-ray findings and CT manifestations were double-blindedly analyzed according to Receiver Operating Characteristic(ROC) curve. Results Calculated in the diagnostic threshold,the sensitivity,specificity,accuracy,positive prediction value and negative prediction value of X-ray findings were respectively 81.6%,61.9%,74.6%,76.3% and 69.2%,and those of CT findings were 93.4%,88.1%,91.5%,92.2% and 89.8%.Areas under the ROC curve(Az=0.958±0.043) of CT findings were significantly higher those of chest X-ray findings(Az=0.758±0.102) and chest X-ray findings with PPD,TB-AB tests(Az=0.833±0.071,P<0.01). Conclusion Chest CT scan plays the important role in diagnosis and differentiate diagnosis of smear negative pulmonary tuberculosis suspects.