Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Previous left - sided pneumothorax is not readily apparent . Left chest pacemaker with right ventricular lead is unchanged . Lung volumes are slightly low ; however , no opacities concerning for infectious processes are noted . Vague opacity in the left lung just medial to the pacer pack is stable . This non-resolving opacity should be evaluated with a CT on a non-emergent basis . Cardiomediastinal silhouette is mildly enlarged . No obvious pleural effusions .
    OUTPUT:
    
1 ) No acute intrathoracic process . Resolved pneumothorax . 2 ) Vague opacity in the left lung just medial to the pacer pack is stable . This non-resolving opacity should be evaluated with a CT on a non-emergent basis .