Liver Iron Concentration Calculator

Convert liver R2* (s⁻¹) from MRI relaxometry to liver iron concentration (LIC) in mg Fe/g dry liver, at 1.5 T or 3.0 T, with severity grading for hepatic iron overload.

Disclaimer:

Provided "as is" without warranty of any kind, express or implied, including accuracy, completeness or fitness for a particular purpose. For educational purposes only. The user is solely responsible for verifying results against the source guideline and for all clinical decisions.

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How it works

Place 3–4 regions of interest (2–4 cm) in liver parenchyma, avoiding vessels, edges and artifact, ideally in both lobes. Enter each ROI's R2* value; the calculator reports the count, range and mean R2*, then converts the mean to LIC. Different formulas must be used for 1.5 T and 3.0 T, so choose the field strength the study was acquired at.

Formulas

Calibration1.5 T3.0 T
SAR Hepatic Iron Overload DFP (default)LIC = 0.027 × R2* − 0.26LIC = 0.015 × R2* − 0.32
Hernando et al., Radiology 2023LIC = 0.02603 × R2* − 0.16LIC = 0.01349 × R2* − 0.03

LIC in mg Fe/g dry liver; R2* in s⁻¹ (R2* = 1000 / T2* in ms). The SAR panel values are the reporting guidance from the Society of Abdominal Radiology Hepatic Iron Overload Disease-Focused Panel, derived from the multi-centre, multi-vendor study later published by Hernando et al. The two calibrations differ by a few tenths of a mg/g; either is acceptable, but be consistent within a practice.

Severity of iron overload

LIC (mg Fe/g)R2* at 1.5 T (s⁻¹)R2* at 3.0 T (s⁻¹)Severity
< 1.8< 76< 141None (normal)
1.8 – 3.276 – 127141 – 234Mild
3.2 – 7.0128 – 268235 – 487Moderate
7.0 – 15.0269 – 564488 – 1020Severe
> 15.0> 565> 1021Extreme

References

  1. Society of Abdominal Radiology, Hepatic Iron Overload Disease-Focused Panel. R2* liver iron quantification: ROI placement, calibration and reporting (panel reporting guidance). www.abdominalradiology.org
  2. Reeder SB, Yokoo T, França M, et al. Quantification of Liver Iron Overload with MRI: Review and Guidelines from the ESGAR and SAR. Radiology. 2023;307(1):e221856. doi:10.1148/radiol.221856 · free full text
  3. Hernando D, Zhao R, Yuan Q, et al. Multicenter Reproducibility of Liver Iron Quantification with 1.5-T and 3.0-T MRI. Radiology. 2023;306(2):e213256. doi:10.1148/radiol.213256 · free full text
  4. Wood JC, Enriquez C, Ghugre N, 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):1460–1465. doi:10.1182/blood-2004-10-3982 · free full text