Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest . Low lung volumes are again noted . Increased interstitial markings seen more extensive at the bases , is again noted and is compatible with patient 's known IPF . Overall , the appearance is not significantly changed . There is no definite new consolidation . The cardiomediastinal silhouette is within normal limits . No acute osseous abnormality is identified .
    OUTPUT:
    
Chronic changes compatible with patient 's known IPF , without definite superimposed acute cardiopulmonary process , noting that subtle change would be difficult to discern .