Intrasubject subcortical quantitative referencing to boost MRI sensitivity to Parkinson's disease

Area of Science:

• Neuroimaging
• Neurodegenerative Diseases
• Biomarkers

Background:

• Postmortem studies indicate iron accumulation in the substantia nigra of Parkinson's disease (PD) patients.
• MRI-R2* mapping is a non-invasive method to estimate iron concentration.
• High inter-subject variability in R2* values complicates disease assessment.

Purpose of the Study:

• To assess R2* changes in the substantia nigra of Parkinson's disease patients compared to controls.
• To introduce and validate a novel method, intrasubject subcortical quantitative referencing (ISQR), to reduce variability.
• To explore the correlation between R2* values and clinical features of Parkinson's disease.

Main Methods:

• A multicenter transversal study involving 98 PD patients and 65 matched controls.
• MRI-R2* mapping acquired at 3 Tesla across 12 clinical centers.
• Development and application of the ISQR strategy using the red nucleus as an intra-subject reference.

Main Results:

• R2* values were significantly increased in the substantia nigra of PD patients compared to controls.
• The ISQR strategy significantly reduced variability and highlighted increased R2* in the substantia nigra.
• ISQR-derived R2* values in the substantia nigra correlated significantly with disease duration and severity (Hoehn & Yahr scale).

Conclusions:

• The ISQR strategy effectively reduces variability unrelated to Parkinson's disease.
• ISQR is a valuable tool for evaluating iron accumulation in the substantia nigra in Parkinson's disease.
• This method supports the use of MRI-R2* mapping for Parkinson's disease assessment and monitoring.