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Deterministic Tractography of the Nigrostriatal-Nigropallidal Pathway in Parkinson's Disease.

Tan WQ, Yeoh CS, Rumpel H, Nadkarni N, Lye WK, Tan EK, Chan LL - Sci Rep (2015)

Bottom Line: 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).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.

View Article: PubMed Central - PubMed

Affiliation: Duke-NUS Graduate Medical School, 8 College Rd, Singapore 169857.

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.

No MeSH data available.


Related in: MedlinePlus

Isolating the nigrostriatal-nigropallidal tract complex on DTI.Midbrain (A) axial colour-FA and (B) coronal trace maps. First 3-mm diameter disk-shaped ROI is placed in the ventral substantia nigra (SN, green band), inferior to the level of the red nucleus (RN). Basal ganglia (C) axial and (D) coronal trace maps. Second “target” 4 mm diameter sphere ROI is placed in the ipsilateral inferomedial globus pallidus (GP). Put = putamen. Isolated nigrostriatal-nigropallidal (NSP) tract complex in a (E) control subject and (F) PD patient. The NSP tract in the PD patient was sparser than that in the control subject.
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f1: Isolating the nigrostriatal-nigropallidal tract complex on DTI.Midbrain (A) axial colour-FA and (B) coronal trace maps. First 3-mm diameter disk-shaped ROI is placed in the ventral substantia nigra (SN, green band), inferior to the level of the red nucleus (RN). Basal ganglia (C) axial and (D) coronal trace maps. Second “target” 4 mm diameter sphere ROI is placed in the ipsilateral inferomedial globus pallidus (GP). Put = putamen. Isolated nigrostriatal-nigropallidal (NSP) tract complex in a (E) control subject and (F) PD patient. The NSP tract in the PD patient was sparser than that in the control subject.

Mentions: The characteristics of subjects and averaged NSP tract parameters are depicted in Table 1. Visually, the NSP tracks from PD patients were sparser than the control subjects (Fig. 1E,F) and this was reflected in the streamline count. Average FA (p = 0.002) and streamline count (p < 0.001) were lower in the PD compared to the control group. MD and RD were significantly higher in the PD group (p < 0.05). Intraclass correlation coefficient values were excellent (>0.8) for the tract measures (Table 2).


Deterministic Tractography of the Nigrostriatal-Nigropallidal Pathway in Parkinson's Disease.

Tan WQ, Yeoh CS, Rumpel H, Nadkarni N, Lye WK, Tan EK, Chan LL - Sci Rep (2015)

Isolating the nigrostriatal-nigropallidal tract complex on DTI.Midbrain (A) axial colour-FA and (B) coronal trace maps. First 3-mm diameter disk-shaped ROI is placed in the ventral substantia nigra (SN, green band), inferior to the level of the red nucleus (RN). Basal ganglia (C) axial and (D) coronal trace maps. Second “target” 4 mm diameter sphere ROI is placed in the ipsilateral inferomedial globus pallidus (GP). Put = putamen. Isolated nigrostriatal-nigropallidal (NSP) tract complex in a (E) control subject and (F) PD patient. The NSP tract in the PD patient was sparser than that in the control subject.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664862&req=5

f1: Isolating the nigrostriatal-nigropallidal tract complex on DTI.Midbrain (A) axial colour-FA and (B) coronal trace maps. First 3-mm diameter disk-shaped ROI is placed in the ventral substantia nigra (SN, green band), inferior to the level of the red nucleus (RN). Basal ganglia (C) axial and (D) coronal trace maps. Second “target” 4 mm diameter sphere ROI is placed in the ipsilateral inferomedial globus pallidus (GP). Put = putamen. Isolated nigrostriatal-nigropallidal (NSP) tract complex in a (E) control subject and (F) PD patient. The NSP tract in the PD patient was sparser than that in the control subject.
Mentions: The characteristics of subjects and averaged NSP tract parameters are depicted in Table 1. Visually, the NSP tracks from PD patients were sparser than the control subjects (Fig. 1E,F) and this was reflected in the streamline count. Average FA (p = 0.002) and streamline count (p < 0.001) were lower in the PD compared to the control group. MD and RD were significantly higher in the PD group (p < 0.05). Intraclass correlation coefficient values were excellent (>0.8) for the tract measures (Table 2).

Bottom Line: 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).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.

View Article: PubMed Central - PubMed

Affiliation: Duke-NUS Graduate Medical School, 8 College Rd, Singapore 169857.

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.

No MeSH data available.


Related in: MedlinePlus