Can ultrasound be of any help in the diagnosis of alveolar-interstitial 
syndrome? In a prospective study, we examined 250 consecutive patients in a 
medical intensive care unit: 121 patients with radiologic alveolar-interstitial 
syndrome (disseminated to the whole lung, n = 92; localized, n = 29) and 129 
patients without radiologic evidence of alveolar-interstitial syndrome. The 
antero-lateral chest wall was examined using ultrasound. The ultrasonic feature 
of multiple comet-tail artifacts fanning out from the lung surface was 
investigated. This pattern was present all over the lung surface in 86 of 92 
patients with diffuse alveolar-interstitial syndrome (sensitivity of 93.4%). It 
was absent or confined to the last lateral intercostal space in 120 of 129 
patients with normal chest X-ray (specificity of 93.0%). Tomodensitometric 
correlations showed that the thickened sub-pleural interlobular septa, as well 
as ground-glass areas, two lesions present in acute pulmonary edema, were 
associated with the presence of the comet-tail artifact. In conclusion, presence 
of the comet-tail artifact allowed diagnosis of alveolar-interstitial syndrome.