Comparative estimation of pleural effusion volume based on lateral decubitus position of chest x-ray and CT scan imaging.

Previous study using thoracic phantom for estimating fluid volume has been obtained which represents the case of pleural effusion based on the size of the x-ray radiograph. The models are obtained in the form of three equations, the pleural effusion volume as a function of height, length times the height, and area of the radiograph image. The three models of estimation have high linearity with ratio value more than 0.988, higher than the modelling measurement using ultrasonography modality. The modelling is expected to give a contribution on developing method for helping clinicians estimate the pleural effusion volume as a basic for performing fluid aspiration and to monitor the therapy. However, because modelling is developed using phantoms, then to be applied clinically, further research is needed for its application to patients. The height function model yields correlation value of 0.966 and paired T-test value of 0.892. The height times length function model yields correlation value of 0.982 and paired T-test value of 0.611. The area function model yields correlation value of 0.997 and paired T-test value of 0.647. From the three equations, measurement of estimated pleural effusion volume using area function on chest x-ray lateral decubitus position is the most appropriate equation. Corresponding to the results of the measurement of gold standard using a CT scan. Height measurement is the measurement that is the fastest and easiest in the application. Limitation of the study is it only can be done in right lateral decubitus position of the patient, and also cannot be applied to patients with condition such as post lung surgery, massive subpulmonic/ supradiaphragmatic pleural effusion, empyema, an atypical pleural effusion such as septated, encapsulated, loculated pleural effusion and anatomical deformity, scoliosis, or abnormalities of thoracic cavity.