Of the 266 patients who were given a diagnosis, 8 patients were found to have a diagnosis that could be made on imaging (4 with lower respiratory tract infection, 2 with malignancy, 1 with bronchiectasis, and 1 with pulmonary fibrosis). Although made explicit for the 2 cases with malignancy, it is only implied that the other 6 patients had normal chest radiography and that the diagnosis was made by other means (ie, chest CT). Additionally, the cases of malignancy were suspected on the Chronic Cough The diagnostic performance of chest radiography varies among the reviewed literature. In a systematic review of the literature, Piccazzo et al [30] reported a high negative predictive value for chest radiography in the evaluation of active and inactive tuberculosis. Abnormalities on chest radiography did have a lower specificity, and findings, which were equivalent the authors concluded, should prompt consideration for CT as this modality was shown to have better performance for both active and inactive tuberculosis. Colaci et al [31] prospectively evaluated 107 consecutive patients with systemic sclerosis with both radiography and HRCT. Their study showed strong correlation between radiographic and HRCT findings of interstitial lung disease, with strong association between cough symptoms and HRCT findings. Interstitial lung pattern and restrictive PFT was more commonly identified than airway involvement and obstructive disease. The authors, however, did not publish sensitivity or specificity for radiography [31]. The diagnostic performance of radiography for other patterns of lung disease may be worse. In a retrospective analysis of 236 patients with CT-proven bronchiectasis, Altenburg et al [32] reported that up to 34% of chest radiographs were reported unremarkable. As mentioned above, the most common CT findings in those patients with chronic cough with normal radiographs were in fact bronchiectasis (28%) and bronchial wall thickening (21%) [3].
Chronic Cough. Of the 266 patients who were given a diagnosis, 8 patients were found to have a diagnosis that could be made on imaging (4 with lower respiratory tract infection, 2 with malignancy, 1 with bronchiectasis, and 1 with pulmonary fibrosis). Although made explicit for the 2 cases with malignancy, it is only implied that the other 6 patients had normal chest radiography and that the diagnosis was made by other means (ie, chest CT). Additionally, the cases of malignancy were suspected on the Chronic Cough The diagnostic performance of chest radiography varies among the reviewed literature. In a systematic review of the literature, Piccazzo et al [30] reported a high negative predictive value for chest radiography in the evaluation of active and inactive tuberculosis. Abnormalities on chest radiography did have a lower specificity, and findings, which were equivalent the authors concluded, should prompt consideration for CT as this modality was shown to have better performance for both active and inactive tuberculosis. Colaci et al [31] prospectively evaluated 107 consecutive patients with systemic sclerosis with both radiography and HRCT. Their study showed strong correlation between radiographic and HRCT findings of interstitial lung disease, with strong association between cough symptoms and HRCT findings. Interstitial lung pattern and restrictive PFT was more commonly identified than airway involvement and obstructive disease. The authors, however, did not publish sensitivity or specificity for radiography [31]. The diagnostic performance of radiography for other patterns of lung disease may be worse. In a retrospective analysis of 236 patients with CT-proven bronchiectasis, Altenburg et al [32] reported that up to 34% of chest radiographs were reported unremarkable. As mentioned above, the most common CT findings in those patients with chronic cough with normal radiographs were in fact bronchiectasis (28%) and bronchial wall thickening (21%) [3].