Comparing Sensitivity of Ultrasonography and Plain Chest Radiography in Detection of Pneumonia; a Diagnostic Value Study

Introduction: Rapid detection of pneumonia and early initiation of antibiotic therapy are associated with better prognosis in patients. The present study was designed aiming to evaluate the sensitivity of chest ultrasonography performed by emergency medicine specialists in detection of pneumonia and comparing it with plain radiography. Methods: In the present diagnostic accuracy study, patients presenting to the emergency department with clinical symptoms of lung infection underwent plain radiography, ultrasonography, and computed tomography (CT) scan of chest and the screening performance characteristics of plain radiography and ultrasonography were compared considering CT scan findings as the gold standard. Results: 280 patients with the mean age of 56.47 § 19.79 (10 – 92) years were studied (57.1% male). The results of chest CT scan were indicative of infection symptoms being present and confirmed pneumonia diagnosis for all the patients. Out of the 280 cases of pneumonia confirmed via chest CT scan, 17 (6.1%) cases were not detected via ultrasonography and 48 (17.1%) cases were missed by chest radiography (false negative cases). No false positive case was reported by ultrasonography or chest x-ray. Since all of the CT scans were positive, no comment can be made regarding the specificity of the evaluated tests, but sensitivity of ultrasonography and plain radiography were 93.92 (90.28 – 96.31) and 82.85 (77.81 – 86.97), respectively (p = 0.583). Conclusion: Based on the findings of the present study, although the sensitivity of ultrasonography in detection of pneumonia was significantly higher than chest x-ray, overall the screening performance characteristics of the 2 tests were not significantly different. Therefore, considering characteristics such as safety, low cost, being portable, and being available, ultrasonography seems to be a reasonable tool for screening and diagnosis of patients with pneumonia.