Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Streaky left basilar opacity with volume loss is compatible with scarring as seen on prior exams . Elsewhere , the lungs are clear without consolidation . Cardiomediastinal silhouette is stable . No acute osseous abnormalities .
    OUTPUT:
    
Chronic changes at the left lung base . No definite acute cardiopulmonary process .