Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Persistently low lung volumes . Overall improvement of ground - glass opacities better seen on prior CT . There are however peribronchial opacities in the left upper lobe and bilateral lower lobes , left greater than right . The cardiomediastinal and hilar contours are stable . The pleural surfaces are normal . Degenerative changes of the thoracic spine .
    OUTPUT:
    
Left upper lobe and bilateral lower lobe opacities . Some may represent chronic fibrotic changes while some may represent resolving infection .