Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left apical pneumothorax now measures 3 .3 cm in craniocaudal dimension , previously 4 .7 cm . There is no cardiomediastinal shift . Lungs are otherwise clear . There is redemonstration of known left clavicular fracture .
    OUTPUT:
    
Left apical pneumothorax now measures approximately 3 .3 cm in craniocaudal dimension , slightly decreased in size since prior examination .