Neurite orientation dispersion and density imaging of the nigrostriatal pathway in Parkinson's disease: Retrograde degeneration observed by tract-profile analysis.
INTRODUCTION
Parkinson's disease (PD) is marked by the degeneration of dopaminergic neurons in the nigrostriatal pathway (NSP). We aimed to identify the microstructural changes in the NSP of PD patients using neurite orientation dispersion and density imaging (NODDI).


METHODS
NSPs of 29 PD patients, who were retrospectively selected from patients previously admitted to our institution, and 29 age- and gender-matched healthy controls were isolated via deterministic tractography. The NODDI indices, intracellular volume fraction (Vic), orientation dispersion index (OD), and isotropic volume fraction (Viso) were compared between the two groups. The significant results were assessed with a tract-profile analysis. The correlation between indices and disease duration or motor symptom severity was evaluated with the Pearson's correlation test.


RESULTS
The contralateral distal Vic (p = 0.00028) of the nigrostriatal pathway was significantly lower in PD patients than in healthy controls. No correlations were detected between any of the indices and disease duration or motor symptom severity.


CONCLUSIONS
NODDI can be used to identify retrograde degeneration of the NSP in PD patients and might be useful for monitoring the disease progression of PD.
['Andica|Christina|C|', 'Kamagata|Koji|K|', 'Hatano|Taku|T|', 'Okuzumi|Ayami|A|', 'Saito|Asami|A|', 'Nakazawa|Misaki|M|', 'Ueda|Ryo|R|', 'Motoi|Yumiko|Y|', 'Kamiya|Kouhei|K|', 'Suzuki|Michimasa|M|', 'Hori|Masaaki|M|', 'Kumamaru|Kanako K|KK|', 'Hattori|Nobutaka|N|', 'Aoki|Shigeki|S|']
D000368:Aged D016022:Case-Control Studies D003342:Corpus Striatum D056324:Diffusion Tensor Imaging D059290:Dopaminergic Neurons D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D009434:Neural Pathways D016501:Neurites D010300:Parkinson Disease D012183:Retrograde Degeneration D012189:Retrospective Studies D013378:Substantia Nigra
Neurite orientation dispersion and density imaging Nigrostriatal pathway Parkinson's disease Retrograde degeneration Tract-profile analysis Diffusion tensor imaging