A 14-year-old male is brought to the Emergency Department by ambulance following an alleged assault. He has sustained a single stab wound to his right mid-back, approximately 3cm lateral to the spine at the level of T11. The wound appears to be approximately 4cm in length. The incident occurred approximately 30 minutes before arrival. The patient is conscious and complaining of right-sided chest pain and mild shortness of breath.

Observations:

Heart rate: 110 beats per minute

Respiratory rate: 24 breaths per minute

Blood pressure: 112/68 mmHg

Temperature: 36.8°C

Oxygen saturation: 95% on room air

GCS: 15/15

On examination, there is a single stab wound to the right mid-back with minimal external bleeding. The wound edges appear clean. There is tenderness around the wound site and the right hemithorax. Air entry is slightly reduced in the right lung base with occasional crackles. The abdomen is soft and non-tender.

Past medical history is unremarkable. He takes no regular medications and has no known allergies.

Bedside eFAST reveals no pneumothorax, tamponade or free fluid in the abdomen. 

What is the most appropriate definitive imaging strategy for this patient?