P3.06. MULTICENTRIC STUDY OF LONGITUDINAL CHANGES IN NEUROMELANIN MRI SIGNAL AS A PROGRESSION MARKER IN PARKINSON'S DISEASE
Alexis Baron1,2,3,4, Rahul Gaurav1,2,3,4, François-Xavier Lejeune1,2,6, Romain Valabrègue1,2,3, Isabelle Arnulf1,2,5, Jean-Christophe Corvol1,2,5, Marie Vidailhet1,2,4, Stéphane Lehéricy1,2,3,4
1 Sorbonne University, 21 rue de l'École de Médecine, Paris, France
2 Paris Brain Institute /CNRS UMR 7225/INSERM U 1127, Paris, France
3 Paris Brain Institute, Neuroimaging Research Center – CENIR, Hôpital Pitié-Salpêtrière 47 bd de l'Hôpital, Paris, France
4 Paris Brain Institute, Movement Investigations and Therapeutics (MOV'IT) team, Hôpital Pitié-Salpêtrière 47 bd de l'Hôpital, Paris, France
5 Paris Brain Institute, Neuroscience Clinical Investigation Center (CIC), Hôpital Pitié-Salpêtrière 47 bd de l'Hôpital, Paris, France
6 Paris Brain Institute, Data analyse core (DAC), Hôpital Pitié-Salpêtrière 47 bd de l'Hôpital,Paris, France.
INTRODUCTION: Neuromelanin-sensitive MRI (NM-MRI) offers a promising avenue for non-invasive assessment of dopaminergic neuron integrity in Parkinson’s disease (PD). Monitoring disease progression remains a major challenge in clinical practice and research.
AIM(S): This study aimed to evaluate NM-MRI markers as potential biomarkers of PD progression, with a particular focus on longitudinal changes in the substantia nigra (SN).
METHOD(S): A total of 483 participants from two cohorts were included: healthy volunteers, patients with isolated REM sleep behavior disorder (iRBD), and PD patients. All underwent 3T NM-MRI. Automated segmentation algorithms were used to extract SN volumes, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR).
RESULTS: At baseline, PD patients showed significantly lower SN volume, SNR, and CNR compared to both controls and iRBD patients, indicating neuromelanin loss. Longitudinal analyses revealed progressive reductions in these markers across patient groups, with a notable effect of sex. These changes reflect the ongoing degeneration of dopaminergic neurons in PD.
CONCLUSIONS: NM-MRI provides a sensitive, non-invasive tool for tracking PD-related neurodegeneration. Its potential as a biomarker for disease progression and therapeutic response is reinforced by longitudinal evidence. Moreover, artificial intelligence proves essential for robust image analysis and may enhance future diagnostic precision. Further studies are warranted to validate these findings and optimize clinical applications.
FINANCIAL SUPPORT: The PhD is supported through dual funding from Novartis and the Michael J. Fox Foundation for Parkinson's Research.