Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes persist without focal consolidation . Retrocardiac region is incompletely assessed due to obscuration by battery pack of neural stimulator . Crowding of the vasculature and increased interstitial markings is seemingly unchanged from multiple previous examinations , likely secondary to crowding due to low lung volumes . Cardiac silhouette remains mildly enlarged .
    OUTPUT:
    
No acute intrathoracic process .