Computed Tomography in Differential Diagnosis of Exudative and Transudative Pleural Effusions

Objective: To differentiate between exudative and transudative pleural effusions by using CT attenuation values and CT appearances. Methods: The retrospective study reviewed 132 patients who were diagnosed of pleural effusions in 2007-2014. All patients were evaluated by chest CT images before or after pleural tapping within 2 days. Pleural effusions were classified as exudates or transudates based on Light’s criteria.1 Pre-contrast and post-contrast CT images were reviewed by measuring the mean attenuation values of pleural effusions and the associated CT findings. Results: Pleural effusions were 112 exudates and 20 transudates. Exudate group had significant higher mean attenuation values, compared with a transudate, in both pre-contrast (12.8±5.0 HU vs. 9.4±5.2 HU; p