Diagnostic Examination of Exudative or Transudative Form of Pleural Effusion Based on CT Scan and Ultrasound Findings

Abstract

Background: Pleural effusion, characterized by the accumulation of excess fluid in the pleural space, necessitates classification into exudative or transudative types to ascertain its etiology. Light's criteria are the standard for this classification, with the serum-pleural fluid albumin gradient serving as an additional tool. Objectives: This study aimed to evaluate the efficacy of ultrasonography and computed tomography (CT) scans in differentiating between exudative and transudative pleural effusions. Methods: A descriptive study was conducted on 72 patients with pleural effusion at Hazrat-e-Rasool Hospital during 2021 - 2022. Simultaneous measurements of pleural fluid and serum albumin levels were performed, and the results of CT scans and ultrasounds were assessed. The albumin gradient and Light's criteria were employed to classify the pleural fluid type. The study also evaluated the predictive value of CT scan and ultrasound findings for the final diagnosis. Data were collected using questionnaires and analyzed with SPSS version 24. Results: The mean age of the 72 patients was 56.1 years, comprising 39 men and 33 women. Eighteen patients had transudative fluid, while 54 patients (75%) had exudative fluid. Pulmonary edema was present in 21 patients (29.2%), lung infections in 29 patients (40.3%), pleural nodules in 11 patients (15.3%), and pleural effusion loculation in 20 patients (27.8%). Pleural thickening exceeding one centimeter was observed in 32 individuals (44.4%). A significant correlation was found between pleural thickening, nodules, fluid loculation, and the type of pleural fluid. Ultrasound demonstrated mild to moderate agreement with CT scans in diagnosing pleural nodules and other lung abnormalities but was less reliable in detecting pleural fluid echogenicity. Conclusions: Imaging features on ultrasound and CT scan, such as pulmonary edema, evidence of pulmonary parenchymal infection, pleural nodules, and pleural thickening, indicate that these criteria are effective in determining the nature of pleural fluid. Therefore, integrating CT scan and ultrasound with existing laboratory criteria could enhance the accuracy of fluid type diagnosis and improve the management of patients with pleural effusion.