A 58-year-old man with a 20-year history of smoking presents with a 2-week history of hemoptysis and progressive dyspnea. On examination, he has reduced air entry on the right side. Chest X-ray shows a 4 cm irregular opacity in the right upper lobe with hilar lymphadenopathy. Sputum cytology is negative for malignancy. What is the most appropriate next imaging modality to characterize the lesion and assess for metastases?