Figure 1.

Qualitative and quantitative pleural fluid characteristics by ultrasound. (A) Pleural effusions were qualitatively characterized as being homogeneously anechoic or as having floating debris, fibrinous stranding, or loculations. Most homogeneously anechoic pleural effusions were transudates, whereas those with floating debris, fibrinous stranding, or loculations were mostly exudates. (B) Pleural fluid echogenicity was quantified by measuring pixel density. Exudates had a significantly higher median pixel density compared with transudates.