Lung ultrasonography for community-acquired pneumonia diagnosis.

Over the past two decades, several studies have assessed the performance of lung ultrasonography in the diagnosis of community-acquired pneumonia (CAP). The performance of this diagnostic tool, when used by clinicians other than radiologists, is excellent, with an area under the curve of 0.97, 92% sensitivity, and 93% specificity according to a recent meta-analysis including 5,108 patients. When ultrasonography is compared with chest CT-scan, sensitivity ranged from 68% to 98% and specificity from 61% to 98%. Compared with chest x-ray, ultrasonography seems more sensitive and specific. Lung ultrasonography can thus be considered a reliable tool for the diagnosis of CAP and may serve as a first-line imaging modality, provided that operators have received adequate training. Lung ultrasonography is particularly indicated in patients with acute respiratory failure, as good quality chest x-ray is difficult to perform in these patients. When diagnostic uncertainties remain after this radiological and clinical evaluation, low-dose chest CT-scan is recommended.