The Comet-tail Artifact

TLDR

Ultrasound may aid in diagnosing alveolar‑interstitial syndrome. In a prospective study of 250 ICU patients, the antero‑lateral chest wall was examined by ultrasound to detect multiple comet‑tail artifacts fanning from the lung surface. The comet‑tail artifact was detected over the entire lung surface in 93 % of patients with diffuse alveolar‑interstitial syndrome (sensitivity 93.4 %) and was absent or limited to a single intercostal space in 93 % of patients with normal chest X‑rays (specificity 93.0 %), correlating with sub‑pleural septal thickening and ground‑glass opacities, thereby enabling accurate diagnosis of the syndrome.

Abstract

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.