Quantifying Brain Iron in Hereditary Hemochromatosis Using R2* and Susceptibility Mapping

Area of Science:

• Neuroimaging
• Neurodegeneration
• Medical Physics

Background:

• Brain iron dyshomeostasis is linked to neurodegeneration.
• Hereditary hemochromatosis causes systemic iron overload.
• Evidence of increased brain iron in hereditary hemochromatosis is limited.

Purpose of the Study:

• To noninvasively quantify brain iron in hereditary hemochromatosis patients.
• To compare brain iron levels between patients and healthy controls.
• To assess the utility of quantitative susceptibility mapping (QSM) and R2* mapping for brain iron quantification.

Main Methods:

• Fifty-two hereditary hemochromatosis patients and 47 controls underwent 3T MRI.
• Multiecho gradient-echo sequences were used to acquire QSM and R2* data.
• Deep gray matter regions were segmented to calculate mean susceptibility and R2* relaxation rates.

Main Results:

• Elevated iron levels were observed in the caudate nucleus, putamen, pulvinar thalamus, red nucleus, and dentate nucleus of patients.
• The substantia nigra showed increased susceptibility, and the thalamus showed an increased R2* relaxation rate compared to controls.
• Both QSM and R2* methods indicated abnormal brain iron levels in patients.

Conclusions:

• Quantitative susceptibility mapping and R2* mapping reveal abnormal brain iron levels in hereditary hemochromatosis.
• These MR imaging techniques can be acquired simultaneously and are complementary for deep gray matter iron quantification.
• Findings support the role of brain iron in hereditary hemochromatosis-associated neurodegeneration.