Rasheed Waqas, Qureshi Ruby, Jabeen Naila, Shah Hyder A, Naseem Khan Rashid
Pulmonology, Liaquat College of Medicine & Dentistry, Darul Sehat Hospital, Karachi, PAK.
Radiology, South City Hospital, Karachi, PAK.
Cureus. 2020 Jun 5;12(6):e8467. doi: 10.7759/cureus.8467.
Introduction Pulmonary tuberculosis (PTB) is caused by species of organisms in the Mycobacterium tuberculosis complex. It is a major public health problem worldwide and is endemic in Pakistan. Various clinical and biochemical markers exist for its diagnosis. Radiology has an important role in the diagnosis of PTB. Initially, a chest radiograph is warranted for PTB evaluation. High-resolution computed tomography (HRCT) also has high sensitivity and specificity for PTB diagnosis. Features of primary TB include consolidation, lymphadenopathy, pleural effusion and miliary nodules whereas post-primary TB include apical consolidation, nodules and cavitation. The aim of this study was to determine the diagnostic accuracy of HRCT chest in diagnosing sputum smear positive and smear negative PTB. Methods A cross-sectional study was conducted at a large tertiary care teaching hospital. A retrospective review of medical records of patients who underwent HRCT chest and sputum acid-fast bacillus (AFB) direct smear and AFB culture for suspicion of PTB was undertaken. All HRCT chest examinations were performed on multislice computed tomography (CT) scanner. On HRCT, PTB was defined as the presence of consolidation, centrilobular nodules, branching nodules with tree in bud appearance with or without lymphadenopathy and pleural effusion. Diagnostic accuracy of HRCT including sensitivity, specificity, positive and negative predictive values was calculated using 2 x 2 table, taking findings of AFB culture as a gold standard. Results A total of 108 patients were included in this study with a mean age of 51.85 ± 16.86 years. Diagnostic accuracy of HRCT in diagnosing PTB was found to be 84.26% with sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 89.09%, 79.25%, 81.67%, and 87.50%, respectively. In sputum smear positive patients, HRCT has diagnostic accuracy, sensitivity, specificity, PPV and NPV of 87.50%, 88.57%, 84.62%, 93.94%, and 73.33%, respectively. In sputum smear negative patients, HRCT has diagnostic accuracy, sensitivity, specificity, PPV and NPV of 81.67%, 90.00%, 77.50%, 66.67%, and 93.94%, respectively. Conclusion HRCT has high sensitivity in diagnosing sputum smear positive and sputum smear negative PTB. The specificity of HRCT in diagnosing sputum smear positive PTB was high, whereas it was slightly low in diagnosing sputum smear negative PTB. Overall diagnostic accuracy of HRCT was high in diagnosing PTB.
引言
肺结核（PTB）由结核分枝杆菌复合群中的生物体引起。它是全球主要的公共卫生问题，在巴基斯坦呈地方性流行。其诊断存在多种临床和生化标志物。放射学在PTB的诊断中起着重要作用。最初，胸部X光片是评估PTB所必需的。高分辨率计算机断层扫描（HRCT）对PTB诊断也具有高敏感性和特异性。原发性肺结核的特征包括实变、淋巴结肿大、胸腔积液和粟粒结节，而继发性肺结核包括肺尖实变、结节和空洞。本研究的目的是确定胸部HRCT在诊断痰涂片阳性和涂片阴性PTB中的诊断准确性。
方法
在一家大型三级护理教学医院进行了一项横断面研究。对因疑似PTB而接受胸部HRCT、痰抗酸杆菌（AFB）直接涂片和AFB培养的患者的病历进行回顾性分析。所有胸部HRCT检查均在多层计算机断层扫描（CT）扫描仪上进行。在HRCT上，PTB被定义为存在实变、小叶中心结节、具有树芽状外观的分支结节，伴有或不伴有淋巴结肿大和胸腔积液。以AFB培养结果为金标准，使用2×2列联表计算HRCT的诊断准确性，包括敏感性、特异性、阳性预测值和阴性预测值。
结果
本研究共纳入108例患者，平均年龄为51.85±16.86岁。发现HRCT诊断PTB的准确性为84.26%，敏感性、特异性、阳性预测值（PPV）和阴性预测值（NPV）分别为89.09%、79.25%、81.67%和87.50%。在痰涂片阳性患者中，HRCT的诊断准确性、敏感性、特异性、PPV和NPV分别为87.50%、88.57%、84.62%、93.94%和73.33%。在痰涂片阴性患者中，HRCT的诊断准确性、敏感性、特异性、PPV和NPV分别为81.67%、90.00%、77.50%、66.67%和93.94%。
结论
HRCT在诊断痰涂片阳性和痰涂片阴性PTB方面具有高敏感性。HRCT诊断痰涂片阳性PTB的特异性较高，而诊断痰涂片阴性PTB的特异性略低。HRCT在诊断PTB方面的总体诊断准确性较高。
