Iron quantification in Parkinson's disease using an age-based threshold on susceptibility maps: The advantage of local versus entire structure iron content measurements

Publication date: Available online 13 October 2018

Source: Magnetic Resonance Imaging

Author(s): Sean K. Sethi, Shawn J. Kisch, Kiarash Ghassaban, Ali Rajput, Alex Rajput, Paul S. Babyn, Saifeng Liu, Peter Szkup, E. Mark Haacke

Abstract

Background

Elevated brain iron has been observed in Idiopathic Parkinson's disease (IPD) within the deep gray matter. Using quantitative susceptibility mapping (QSM) and a thresholded high-iron region, we quantified iron content in the midbrain of patients with Parkinson's disease as a function of age.

Methods

We used MRI to scan 24 IPD patients at 3-Tesla. Susceptibility-weighted images were collected with the following parameters, TE: 6 and 20 ms, TR: 30 ms, FA: 15°, and resolution: 0.5 × 0.5 × 2.0 mm³. QSM images were reconstructed from the source phase images. Whole-region and thresholded high-iron (RII) region boundaries for the Substantia Nigra (SN) and Red Nucleus (RN) were traced. Iron content was measured via mean susceptibilities and volumes, which were compared between the groups, as well as between right and left side of the structures within groups.

Results

Twenty patients with mild to moderate IPD were used in this study. For the SN, mean RII iron and volumes were higher in IPD compared to HC, while no differences were seen between the groups when considering whole regions for the left SN, and bilaterally for the RN.

Conclusion

Using a two-region of interest analysis on QSM, we showed that abnormal iron occurs in IPD patients in the SN and with greater volumes compared to HC. This may have application as a biomarker for disease diagnosis and early intervention.

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