Glymphatic function assessment in Parkinson's disease using diffusion tensor image analysis along the perivascular space

Introduction: Glymphatic dysfunction can contribute to & alpha;-synucleinopathies. We examined glymphatic function in idiopathic Parkinson's disease (PD) utilizing Diffusion Tensor Image Analysis aLong the Perivascular Space (DTIMethods: This study enrolled consecutive patients diagnosed with de novo PD between June 2017 and March 2019 who underwent brain DTI with concurrent 123I-2 & beta;-carbomethoxy-3 & beta;-(4-iodophenyl)-N-(3-fluoropropyl)nortropane (123I-FP-CIT) SPECT, and age- and sex-matched controls. From DTI-ALPS, the ALPS-index was calculated as a ratio of diffusivities along the x-axis in the region of neural fibers passing vertically to the diffusivities perpendicular to them, which reflected perivascular water motion at the lateral ventricular body level. The ALPS-index of the PD and control groups was compared using Student's t-test; its correlations with clinical scores for motor and cognition (UPDRS-III, MMSE, and MoCA) and striatal dopamine transporter uptake measured by 123I-FP-CIT specific binding ratios (SBRs) were examined using a correlation coefficient.Results: In all, 54 patients in the de novo PD group (31 women, 23 men; mean age, 68.9 & PLUSMN; 9.4 years) and 54 in the control group (mean age, 69.0 & PLUSMN; 10.5 years) were included. The ALPS-index was lower in the PD group than in the controls (1.51 & PLUSMN; 0.22 versus 1.66 & PLUSMN; 0.20; P < 0.001). In the PD group, the ALPS-index negatively correlated with the UPDRS-III score (r = -0.526), and positively correlated with the MMSE (r = 0.377) and MoCA scores (r = 0.382) (all, P < 0.05). No correlation was observed between the ALPS-index and striatal 123I-FP-CIT SBRs (P > 0.05).Conclusions: DTI-ALPS can reveal glymphatic dysfunction in patients with PD, whose severity correlated with motor and cognitive dysfunction, but not striatal dopamine transporter uptake.

Automated summary

DTI-ALPS was used to study glymphatic dysfunction in patients with PD, and it was found that the severity of glymphatic dysfunction was correlated with motor and cognitive dysfunction, but not with striatal dopamine transporter uptake.