Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild cardiomegaly and tortuosity of the thoracic aorta is unchanged from prior study . Hilar contours are unremarkable . Previously identified retrocardiac density is improved compared to prior study . There is trace linear atelectasis at the right lung base . There is re- demonstration of a roughly 1 .5 cm nodule in the right upper lobe unchanged from the prior examination . There are no definite traumatic findings or focal bony lesions though this is greatly limited by diffuse osteopenia .
    OUTPUT:
    
1 . No traumatic findings or focal bone lesions though this is greatly limited by diffuse osteopenia . 2 . Re- demonstration of 15 mm nodule in the right upper lobe which as suggested on prior study , should be further evaluated by CT . 3 . Improving retrocardiac density and right base atelectasis .