Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Semi-upright portable view of the chest demonstrates low lung volumes . No pleural effusion or pneumothorax . Heterogeneous left lung base opacity is present . Mild pulmonary vascular congestion is noted . Hilar and mediastinal silhouettes are unremarkable . Heart size is normal . Multiple surgical clips project over the mediastinum . Sternotomy wires appear intact . Partially imaged upper abdomen is unremarkable . A 4 - mm round density projecting over left lung apex likely represents a calcified granuloma .
    OUTPUT:
    
1 . Low lung volumes with mild pulmonary vascular congestion . 2 . Left lung base heterogeneous opacity can be further assessed with conventional radiographs or CT . Prior exams , if available for comparison , will be helpful .