Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest . Low lung volumes , which accentuate bronchovascular markings and cardiomediastinal contours . The mediastinum is slightly widened in the region of the aortic knob and aorticopulmonary window . Heart size is top normal . There is no pulmonary edema . Right hemidiaphragm is slightly elevated . There is no pleural effusion , focal consolidation , or pneumothorax . Partially imaged upper abdomen is unremarkable . On the lateral view , the normally clear retrosternal space is not well visualized .
    OUTPUT:
    
Widened mediastinum , possibly due to accentuation by low lung volumes , but a discrete mass or acute mediastinal process can not be excluded . Repeat chest radiographs are recommended with improved respiratory effort . Chest CT may also be considered .