Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP single view of the chest has been obtained with patient in semi-upright position . Comparison is made with the next preceding similar study of ___ . The degree of cardiomegaly appears unchanged . Pulmonary congestive pattern with some perivascular haze as before . Comparison of the frontal views demonstrates marked reduction of the right - sided pleural effusion that obliterated the lateral pleural sinus . The left - sided pleural density blunting the pleural sinus and obliterating the diaphragmatic contour appears unchanged . Apical area does not reveal any pneumothorax on the right side .
    OUTPUT:
    
Regression of right - sided pleural effusion , indicating successful performance of thoracotomy on that side . No pneumothorax .