title: Deterministic Tractography of the Nigrostriatal-Nigropallidal Pathway in Parkinson's Disease.
abstract: We hypothesized that deterministic tractography is practical and sensitive to changes in the complex nigrostriatal and nigropallidal pathway (NSP) in Parkinson's disease (PD). Using diffusion tensor imaging (DTI) tractography, we investigated the NSP to evaluate differences between PD patients and controls, and examined their clinico-radiologic correlation. Structural and DTI brain scans were obtained in 40 subjects (21 PD patients and 19 healthy controls). We isolated the NSP using a user-friendly DTI toolkit based on deterministic brute-force tractography. DTI parameters of fractional anisotropy (FA), mean, axial, and radial diffusivity, and streamline count of the NSP were measured. Average FA (p < 0.01) and streamline count (p < 0.001) were significantly lower in the PD compared to control group. Mean diffusivity and radial diffusivity were significantly higher in the PD group (p < 0.05). Average streamline count correlated with the United Parkinson's Disease Rating Scale motor score (p < 0.05). Point-to-point FA profiles of the tract demonstrated peak divergence between PD and control towards the tract midpoint rather than the distal grey matter. Our findings demonstrated a clinically and radiologically practical application of DTI tractography to the NSP in PD, without requiring complex imaging sequences for anatomical localization or segmentation software.
authors.affiliation: Duke-NUS Graduate Medical School, 8 College Rd, Singapore 169857.|Department of Diagnostic Radiology, Singapore General Hospital, Outram Rd, Singapore 169608.
authors.forename: Wen-Qi
authors.initials: WQ
authors.lastname: Tan
authors.affiliation: Department of Diagnostic Radiology, Singapore General Hospital, Outram Rd, Singapore 169608.
authors.forename: Chooi-Sum
authors.initials: CS
authors.lastname: Yeoh
authors.affiliation: Department of Diagnostic Radiology, Singapore General Hospital, Outram Rd, Singapore 169608.
authors.forename: Helmut
authors.initials: H
authors.lastname: Rumpel
authors.affiliation: Duke-NUS Graduate Medical School, 8 College Rd, Singapore 169857.
authors.forename: Nivedita
authors.initials: N
authors.lastname: Nadkarni
authors.affiliation: Duke-NUS Graduate Medical School, 8 College Rd, Singapore 169857.
authors.forename: Weng-Kit
authors.initials: WK
authors.lastname: Lye
authors.affiliation: Duke-NUS Graduate Medical School, 8 College Rd, Singapore 169857.|Department of Neurology, National Neuroscience Institute, Singapore General Hospital Campus, Outram Rd, Singapore 169608.
authors.forename: Eng-King
authors.initials: EK
authors.lastname: Tan
authors.affiliation: Duke-NUS Graduate Medical School, 8 College Rd, Singapore 169857.|Department of Diagnostic Radiology, Singapore General Hospital, Outram Rd, Singapore 169608.
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Chan
mesh_terms: D056324:Diffusion Tensor Imaging; D005260:Female; D005917:Globus Pallidus / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011859:Radiography; D013378:Substantia Nigra / Q000000981:diagnostic imaging* / Q000503:physiopathology