MRI Relaxometry

Iron Quantification Calculator

Converts myocardial and hepatic T2*/R2* measurements into estimated tissue iron concentration, using the calibration curves of Wood, Storey, and Anderson.

Hepatic Iron

Wood et al., 2005
ms
—mg Fe/g dry
—µmol Fe/g
Enter a value
0 37 150 300 µmol/g
Normal< 37
Mild37–150
Moderate150–300
Severe> 300
Method & references

Cardiac — T2* (1.5 T)

Fe (mg/g) = 45 × T2*−1.22

Acceptable myocardial iron is defined as T2* > 20 ms.

Liver — T2* (1.5 T)

Fe (mg/g) = 25.4 / T2* + 0.202

Liver — R2* (1.5 T)

T2* = 1000 / R2* Fe (mg/g) = 25.4 / T2* + 0.202

Liver — T2* (3.0 T)

T2*_eff = 2 / (1/T2* + 11/1000) Fe (mg/g) = 25.4 / T2*_eff + 0.202

Liver — R2* (3.0 T)

T2* = 1000 / R2* T2*_eff = 2 / (1/T2* + 11/1000) Fe (mg/g) = 25.4 / T2*_eff + 0.202

μmol Fe/g = mg Fe/g × 17.907 (Fe molar mass). Severity bands below apply to hepatic μmol Fe/g.

Severityµmol Fe/gmg Fe/g (dry)
Normal< 37< 2.0
Mild37 – 1502.1 – 8.4
Moderate151 – 3008.4 – 16.8
Severe> 300> 16.8

References

  1. Anderson LJ. Assessment of iron overload with T2* magnetic resonance imaging. Prog Cardiovasc Dis. 2011;54(3):287–94.
  2. Carpenter JP, et al. On T2* magnetic resonance and cardiac iron. Circulation. 2011;123(14):1519–28.
  3. Wood JC, et al. MRI R2 and R2* mapping accurately estimates hepatic iron concentration in transfusion-dependent thalassemia and sickle cell disease patients. Blood. 2005;106(4):1460–5.
  4. Storey P, et al. R2* imaging of transfusional iron burden at 3T and comparison with 1.5T. J Magn Reson Imaging. 2007;25(3):540–7.