Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: New homogeneous triangular retrocardiac opacity without air bronchograms . No pleural effusion , pneumothorax or pulmonary edema . Heart size is mildly enlarged with normal mediastinal contour and hila . No bony abnormality .
    OUTPUT:
    
New left lower lobe collapse . Results were conveyed via telephone to Dr . ___ by Dr . ___ on ___ at 2 : 10 p .m . within 10 minutes of observation of findings .