Impact of body fat composition on liver iron overload severity in hemochromatosis: a retrospective MRI analysis

Purpose: To evaluate the correlation between ectopic adipose tissue and iron overload severity in patients with hemochromatosis.

Material and methods: A retrospective cohort of 52 patients who underwent liver iron concentration quantification from January 2015 to October 2023 using a 3.0T MRI scanner. R2* relaxation times and proton density fat fraction (PDFF) were assessed for the entire liver volume and a specific region of interest (ROI) placed in the right lobe. Total body fat (TF), subcutaneous fat (SCF), intermuscular fat (IMF), and visceral fat (VSF) percentages were calculated from a single axial slice at the level of the third lumbar vertebra. Additionally, ratios of IMF-to-VSF, IMF-to-SCF, and SCF-to-VSF were calculated. Standard iron laboratory parameters were collected at least one month prior to MRI. Pearson correlation coefficient was used for correlation analysis.

Results: The mean age of participants was 53.9 ± 19.6 years. IMF positively correlated with R2* values in the ROI (p = 0.005, r_s = 0.382) and entire liver (p = 0.016, r_s = 0.332). Conversely, VSF negatively correlated with R2* values from the ROI (p = < 0.001, r_s = - 0.488) and entire liver (p = < 0.001, r_s = - 0.459). Positive correlations were also found between IMF-to-VSF and R2* of the ROI (p = 0.003, r_s = 0.400) and whole liver (p = 0.008, r_s = 0.364). Ferritin levels positively correlated with R2* values calculated from ROI (p = 0.002, r_s = 0.417) and whole liver volume (p = 0.004, r_s = 0.397). A positive correlation was noted between PDFF of the entire liver and TF (p = 0.024, rs = 0.313).

Conclusion: The percentage of Intermuscular and visceral adipose tissues correlates with the severity of liver iron overload in hemochromatosis patients.