Echogenic swirling pattern as a predictor of malignant pleural effusions in patients with malignancies.

OBJECTIVES: Chest ultrasonography is a useful diagnostic tool for the detection of pleural effusions of different etiologies. Our purpose was to determine whether the echogenic swirling pattern identifiable on real-time chest ultrasonographic images is a predictor of malignant pleural effusions in patients with malignancies.
DESIGN: Medical records of patients undergoing chest ultrasonography in the Tri-Service General Hospital (Taiwan) between January 2000 and December 2002 were reviewed retrospectively. Patients with an echogenic swirling pattern in the pleural effusion, or with malignant diseases associated with pleural effusions, whose pleural fluids had been examined cytologically or whose pleural tissues had been examined pathologically, were enrolled in this study (n = 140). Malignant pleural effusions were defined by the presence of malignant cells in the pleural fluid identified by thoracentesis or by pleural biopsy. The echogenic swirling pattern was defined as numerous echogenic floating particles within the pleural effusion, which swirled in response to respiratory movement or heartbeat. Correlation between malignant pleural effusions and the echogenic swirling pattern was compared in patients with an underlying malignant disease.
RESULTS: In patients with underlying malignancies, malignant pleural effusions were diagnosed in 81.8% of patients with a positive echogenic swirling pattern and in 48% of those with no echogenic swirling pattern. The presence of echogenic swirling was significantly more predictive of malignant pleural effusions than was the absence of echogenic swirling (p < 0.01).
CONCLUSIONS: The echogenic swirling pattern is a useful predictor of possible malignant pleural effusions, and may be a good marker for malignant pleural effusions in patients with underlying malignancies.