In transfusion-dependent anaemias (thalassaemia major), cardiac T2* below 20 ms indicates myocardial iron and below 10 ms severe loading with heart failure risk; liver R2* or T2* estimates liver iron concentration — the numbers guide chelation.
Orient first
- Cardiac T2* thresholds: > 20 ms normal, 10–20 ms mild–moderate, < 10 ms severe (verify local calibration).
- Measure in the interventricular septum on a mid short-axis slice (avoids susceptibility from veins).
- Liver iron concentration is derived from R2* or R2 (FerriScan) with a named calibration.
Acquire the study
- CMR: single breath-hold multi-echo gradient-echo (8+ echoes, ~2–18 ms) at 1.5 T on a mid short-axis slice; liver multi-echo sequence; cine for function.
The manoeuvre
- Mid short-axis multi-echo series: ROI in the septum (full thickness, avoiding blood pool).
- Fit the decay curve; report T2* in ms and the grade.
- Liver ROI avoiding vessels: T2* in ms or R2*; convert to LIC in mg/g with the named calibration.
- Cine: LV EF and volumes (iron cardiomyopathy).
- Compare with prior values over the interval of chelation.
What confirms it
- Cardiac T2* < 20 ms at 1.5 T with a validated method.
What licenses you to exclude it
- Cardiac T2* > 20 ms excludes significant myocardial iron.
The classic misread
- Measuring at 3 T with 1.5 T thresholds.