A 45-year-old man with ulcerative colitis was admitted with bloody diarrhoea and chest pain. Inflammatory markers and high-sensitivity troponin were elevated (C reactive protein 57 mg/L, white cell count 10.65×109/L, neutrophil 6.6×109/L, Troponin-I 663 mmol/L). The ECG showed inferior ST-elevation. Urgent coronary angiography revealed unobstructed coronary arteries. Inpatient cardiovascular magnetic resonance (CMR) was arranged to determine the aetiology of the myocardial infarction with non-obstructive coronary arteries. The imaging protocol at 1.5 T included balanced steady-state free precession cine images, T2-weighted oedema sequences, and early and late gadolinium enhancement (LGE). Native T1 and T2 mapping images provided advanced tissue characterisation.