Cardiac Iron MRI (T2*): Iron Overload & Chelation
Iron overload can kill the heart silently. Cardiac T2* MRI measures the iron before pumping function fails, and it has transformed survival in thalassaemia.
Why T2*
In transfusion-dependent patients, iron accumulates in the myocardium and causes heart failure and arrhythmia, often after a long silent phase, and ejection fraction drops late. Iron shortens T2*, so a mid-septal T2* measurement quantifies myocardial iron non-invasively and early.
Interpreting the number
| Myocardial T2* | Iron status |
|---|---|
| >20 ms | Normal / no significant cardiac iron |
| 10–20 ms | Moderate cardiac iron loading |
| <10 ms | Severe: high risk of heart failure; intensify chelation |
Serial T2* guides iron-chelation therapy and its intensity, and tracks response.
Impact
Since T2*-guided chelation became routine, deaths from cardiac iron overload in thalassaemia have fallen substantially. Liver R2*/T2* is measured in the same sitting.
Sources
- Anderson LJ et al. Cardiovascular T2-star (T2*) magnetic resonance for the early diagnosis of myocardial iron overload. Eur Heart J 2001;22:2171–79.
Educational summary for clinicians; managed by haematology/cardiology. Not medical advice.