Cardiac MRI (CMR)

Cardiac MRI (CMR) is the gold standard for measuring how well your heart pumps. It quantifies the volumes of the left and right ventricles. It also measures the ejection fraction and the muscle mass. And it does this without the geometric guesswork other scans need. CMR also reads the heart tissue itself. 'Late gadolinium enhancement' (LGE) maps focal scar and fibrosis. T1 and T2 mapping measure spread-out fibrosis and swelling. The 'extracellular volume' (ECV) is figured from contrast scans plus your hematocrit. These tools diagnose and grade many heart conditions. The list includes ischemic and non-ischemic cardiomyopathy. It also covers myocarditis, amyloidosis, sarcoidosis, and Fabry disease. CMR uses no radiation. Its downsides are cost and limited scanner access. There is also caution with gadolinium dye in advanced kidney failure. And images blur with an irregular heartbeat or an implanted device. The SCMR, a specialist body, publishes standard protocols.

Last reviewed: June 22, 2026

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