Chest ultrasonography in lung contusion

Study objective: Despite the high prevalence of chest trauma and its high morbidity, lung contusion (LC) often remains undiagnosed in the emergency department (ED). The present study investigates the possible clinical applicability of chest ultrasonography for the diagnosis of LC in the ED in comparison to radiography and CT. Materials and methods: One hundred twenty-one patients admitted to the ED for blunt chest trauma were investigated using ultrasonography by stage III longitudinal scanning of the anterolateral chest wall to detect LC. Data were retrospectively collected in an initial series of 109 patients (group 1) and prospectively in the next 12 patients (group 2). All patients who presented with pneumothorax were excluded. After the ultrasound study, all patients were submitted to chest radiography (CXR) and CT. The sonographic patterns indicative of LC included the following: (1) the alveolointerstitial syndrome (AIS) [defined by increase in B-line artifacts]; and (2) peripheral parenchymal lesion (PPL) [defined by the presence of C-lines: hypoechoic subpleural focal images with or without pleural line gap]. Results: The diagnosis of LC was established by CT scan in 37 patients. If AIS is considered, the sensitivity of ultrasound study was 94.6%, specificity was 96.1%, positive and negative predictive values were 94.6% and 96.1%, respectively, and accuracy was 95.4%. If PPL is alternatively considered, sensitivity and negative predictive values drop to 18.9% and 63.0%, respectively, but both specificity and positive predictive values increased to 100%, with an accuracy of 65.9%. Radiography had sensitivity of 27% and specificity of 100%. Conclusions: Chest ultrasonography can accurately detect LC in blunt trauma victims, in comparison to CT scan.