A new formula for rapid assessment of pericardial effusion volume by computed tomography

RATIONALE AND OBJECTIVES: The aim of this study was to evaluate a new formula for the rapid assessment of pericardial effusion (PE) volume by computed tomography.

MATERIALS AND METHODS: Twenty computed tomographic scans positive for PE were reviewed by two observers. Diameters of PE were measured at four locations. Additionally, PE volume was assessed by volumetry. The correlation between PE diameters and volume was evaluated, and a linear equation was derived for each diameter location. To test validity and reliability of the measurements, intraclass correlation and Bland-Altman analysis were performed.

RESULTS: Good validity was expressed by strong correlations between diameter measurements at all four locations and PE volume (all R values >0.80 and P values <.0001). Intraclass correlation (all coefficients >0.75) and Bland-Altman analysis revealed good interobserver and intraobserver reliability of diameter measurements. The best values were observed for apical diameter measurements. The following linear equation was derived for apical diameter measurements: PE volume = 296 (mL/cm) × apical diameter (cm) - 32 mL.

CONCLUSIONS: PE volume can rapidly be assessed by apical PE diameter measurement using the simplified formula PE volume = 0.3 (L/cm) × apical diameter (cm).