30th April 2024

A 68-year-old man presents with a 3-day history of lower left abdominal pain, which has been gradually worsening.

A 68-year-old man presents with a 3-day history of lower left abdominal pain, which has been gradually worsening. He also reports a change in his bowel habits over the past week, with episodes of constipation followed by loose stools. He has a low-grade fever of 37.6°C. His past medical history includes hypertension for which he takes medication. On examination, there is tenderness in the lower left quadrant of the abdomen, without rebound tenderness. His digital rectal examination is normal.

Which investigation is most appropriate to confirm the diagnosis?