Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Prominent left hilar region secondary to enlarged left main pulmonary artery as seen on chest CT ___ . The lung volumes are normal . Normal size of the cardiac silhouette . Normal hilar and mediastinal structures . No pneumonia , no pulmonary edema . No pleural effusions .
    OUTPUT:
    
Prominent left hilar region secondary to large left main pulmonary artery as seen on chest ct ___ . No pneumonia .