Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable upright frontal view of the chest . Increased interstitial marking are suggestive of vascular congestion and mild interstitial pulmonary edema . A focal opacity in the left mid lung could be edema or superimposed infection . Mild to moderate cardiomegaly and calcification of the aortic knob is relatively unchanged since ___ . There is no large pleural effusion or pneumothorax . There is no acute osseous abnormality .
    OUTPUT:
    
Mild interstitial pulmonary edema . A focal opacity in the left mid lung could be edema or superimposed infection . PA and lateral views when the patient is amenable may help better characterize .