To investigate the clinical value of chest X-ray combined with CT in the diagnosis of early pulmonary infection.

Total of 109 suspected patients with pulmonary infection in our hospital from January 2015 to April 2016 were collected. All cases were examined by 64 slice spiral CT and chest X-ray. The images were analyzed by two senior radiologists and compared with pulmonary infection diagnosis standard. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 64 slice spiral CT scan and chest X-ray examination in early lung infection were compared, respectively.

There were 56 cases diagnosed with pulmonary infection by chest X-ray, 22 cases were never diagnosed and 11 cases were misdiagnosed. X-ray film in pulmonary infection patients mainly showed two lung diffuse, symmetrical micro nodules or reticular infiltration. There were 62 cases diagnosed with pulmonary infection by chest CT, 14 cases never diagnosed and 9 cases misdiagnosed. CT film in pulmonary infection patients mainly showed mixed glass shadow, real change shadow and grid shadow or thin wire like shadow. The sensitivity, specificity, positive predictive value, negative predictive value, and the accuracy rate of combination diagnosis were 94.0%, 92.9%, 95.5%, 90.7% and 93.6%; while chest X-ray were 77.6%, 73.8%, 80.4%, 58.5% and 69.7%, respectively; which were 79.1%, 78.6%, 85.5%, 70.2% and 78.9% in chest CT, respectively. The sensitivity, specificity, positive predictive value, negative predictive value and the accuracy rates of combination diagnosis were significantly higher than those of the single application of chest X-ray or 64 slice spiral CT (χ² = 7.924, 5.065, 6.661, 12.337, 20.290; P = 0.019, 0.024, 0.021, 0.002, 0.000).

The value of combined examination in early diagnosis of pulmonary infection was better than single application of chest X-ray or 64 slice spiral CT examination. It was helpful to improve the accuracy of early diagnosis of pulmonary infection. It was worthy of clinical popularization and application.