Evaluation of hepatic iron concentration heterogeneities using the MRI R2* mapping method

Eur J Radiol. 2019 Jul:116:47-54. doi: 10.1016/j.ejrad.2018.02.011. Epub 2018 Feb 12.

Abstract

Objective: To measure hepatic iron concentration (HIC) heterogeneities using a magnetic resonance R2* mapping method.

Patients and methods: Ninety-four patients with suspected hepatic iron overload and 10 volunteers were included prospectively. A multi-echo R2* sequence with fat saturation and with three post-processing fitting methods (a single exponential decay model with or without truncation, SED and SEDt, and a constant offset model, COS) was compared to a signal intensity ratio method (SIR), considered as the reference. HIC heterogeneity was evaluated from R2* mapping after placing a ROI on each liver segment.

Results: A strong linear correlation between SIR and R2* methods using the SEDt and COS models was observed (r = 0.973 and 0.955, respectively). Volunteers and patient liver variabilities, quantified by mean intra-liver standard deviation (SD) were 1.58 μmol/g (mean range 5.06 μmol/g) and 4.73 μmol/g (mean range 19.08 μmol/g), respectively. For the patient group, the highest HIC was observed in the IVth segment. Heterogeneity increased for patients with an HIC > 60 μmol/g (mean intra-liver SD = 13.90 μmol/g; mean range = 50.60 μmol/g).

Conclusion: This study is the first to demonstrate in vivo HIC heterogeneities using whole-liver mapping analysis. These preliminary results require confirmation through further studies, but might be useful in cases of single ROI analysis.

Keywords: Iron; Liver; MRI; Quantification; R2* mapping.

MeSH terms

  • Adult
  • Female
  • Humans
  • Iron / analysis
  • Iron / metabolism
  • Iron Overload / diagnostic imaging*
  • Iron Overload / metabolism*
  • Iron Overload / pathology
  • Liver / diagnostic imaging*
  • Liver / metabolism*
  • Liver / pathology
  • Magnetic Resonance Imaging / methods*
  • Male
  • Middle Aged
  • Prospective Studies

Substances

  • Iron