Cardiac Stress Perfusion MRI: Detecting Ischaemia
CMR watches contrast wash through the heart muscle under pharmacological stress, a radiation-free way to ask “is there a flow-limiting narrowing?”
How it works
A vasodilator (adenosine, dipyridamole or regadenoson) increases blood flow in normal coronaries but not through significantly stenosed ones. First-pass imaging of gadolinium during stress shows a perfusion defect in the territory supplied by the diseased vessel, compared with rest imaging.
Ischaemia and viability together
Because the same scan includes late gadolinium enhancement, CMR can show both ischaemia (reversible perfusion defect) and scar/viability (LGE) in one sitting, distinguishing a reversible perfusion defect (ischaemia, may benefit from revascularisation) from a matched defect with LGE (established infarct).
Why choose it
- No ionising radiation (vs SPECT/CT), high spatial resolution, and no attenuation artefacts.
- Strong evidence base for guiding revascularisation decisions in stable chest pain.
- Contraindications relate to the stress agent (e.g. asthma/bronchospasm with adenosine) and standard MRI safety.
Sources
- Nagel E et al. Magnetic resonance perfusion or fractional flow reserve in coronary disease (MR-INFORM). N Engl J Med 2019;380:2418–28.
Educational summary for clinicians; stress testing follows local safety protocols. Not medical advice.