Introduction: 
Hereditary hemochromatosis (HH) is a genetic disorder characterized by pathological iron deposition in multiple organs. Iron measurement in the liver has been performed using R2* relaxation mapping and quantitative susceptibility mapping (QSM) in HH subjects. However, evidence of brain iron accumulation in subjects with HH has not been explored previously. The purpose of this study is to map the iron in the deep gray matter (DGM) as well as the dentate nucleus using these methods in HH.

Methods:
Genetically-proven HH subjects and healthy controls (HC) were recruited for this study. All subjects were imaged using a 3T scanner (GE Healthcare). Gradient echo data were collected with the following parameters: TE1=5 ms, TE6=35 ms, ∆TE=5 ms), resolution 0.43 mm×0.43 mm, slice thickness=2 mm. Using TE2-TE6.data, susceptibility [3,4] and R2* maps were constructed.
Regions in the DGM and dentate nucleus were traced by two raters using a full-width half-maximum threshold and reviewed by a neurologist. Mean susceptibility and R2* values were calculated and compared between the groups as well as with reference values [5,6].
Two-tailed t-tests were performed between sides for each structure, and also between HH and HC groups for each structure. 
Iron vs. age plots were generated as well as correlation analyses between all R2* structure data and susceptibility data to show relation between R2* and QSM.

Results:
The raters have an intraclass correlation coefficient of >0.9 for each structure bilaterally for absolute agreement using a two-way random raters model.
We found higher susceptibility in the HH group compared to the HC group bilaterally for all the structures except the GP and THA.
We also found higher R2* relaxation in the HH group compared to the HC group for all the structures except the SN, the left GP and left thalamus.
There is no significant differences in susceptibility and R2* when comparing between sides of each group except for left PT in R2* relaxation for HH group.
R2* measurements correlated well with QSM (R = 0.76). The regression line slope was 0.1428 which is in line with previously-reported research.
QSM and R2* are robust methods for quantifying iron, although QSM showed more sensitivity with higher signal to noise compared to R2*. They may have application in longitudinally tracking brain iron content when iron-chelating agents are used.
Future work will incorporate clinical scores in a multivariate analysis.

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

[Virtual Conference Page](https://event.vconferenceonline.com/microsite/html/login.aspx?id=1551&rlp=1)

[ASNR Website] (https://www.asnr.org//annualmeeting)

[Educational Exhibits](https://www.morressier.com/event/asnr2020exhibit/5e5d0be000701ceba4a26941)