CT-based pleural effusion volume estimation formula demonstrates low accuracy and reproducibility for traumatic...

Area of Science:

• Radiology
• Trauma Surgery
• Thoracic Imaging

Background:

• Accurate estimation of hemothorax volume is crucial for managing acute traumatic hemothorax.
• Computed tomography (CT) is a primary imaging modality for evaluating thoracic trauma.
• Existing CT-based formulas for volume estimation require validation.

Purpose of the Study:

• To assess the accuracy and reproducibility of a CT-based formula (V = d² * h) for estimating acute traumatic hemothorax volume.
• To compare the formula's performance against manual volume measurements.
• To evaluate inter-rater reliability for both methods.

Main Methods:

• Prospective identification of patients with CT-confirmed acute traumatic hemothorax.
• Retrospective volume estimation using the d² * h formula and manual measurement on axial images.
• Subgroup analysis for borderline-sized hemothorax (200-400 mL).
• Repeated measurements by three non-radiologists and Bland-Altman analysis for agreement.

Main Results:

• The CT formula showed wide limits of agreement (-718 to +842 mL) with actual volumes.
• Accuracy was particularly low for borderline-sized hemothorax (limits of agreement -300 to +121 mL).
• Inter-rater variability was significantly higher for the formula compared to manual measurements.

Conclusions:

• The CT-based formula V = d² * h demonstrates significant inaccuracies in estimating hemothorax volume.
• The formula's low accuracy in stratifying volumes near 300 mL limits its clinical utility.
• Manual CT-based volume measurement offers superior accuracy and reproducibility over the estimation formula.