Introduction: This study investigated whether brain tissue pulsatility is associated with features of disease severity in Parkinson's disease (PD).
Methods: Data were extracted from the Parkinson's Progression Markers Initiative among 81 adults with PD (confirmed with DATSCAN™). Brain tissue pulsatility was computed using resting state blood oxygenation level dependent (BOLD) MRI in white matter (WM), referred to as BOLDTP. Motor impairment was assessed using the Movement Disorders Society unified Parkinson's disease rating scale. Factor analysis generated composite scores for cognition and vascular risk burden. A linear regression model examined the association of BOLDTP with age, sex, motor impairment, cognition, vascular risk burden and PD duration. In addition, we investigated whether BOLDTP relates to WM hyperintensity (WMH) volume, WM fractional anisotropy (WM-FA) and striatal binding ratio (SBR) of dopamine transporter.
Results: Motor impairment (t = 2.3, p = .02), vascular burden (t = 2.4, p = .02) and male sex (t = 3.0, p = .003) were independently associated with BOLDTP (r2 = 0.40, p < .001). BOLDTP was correlated with WMH volume (r = 0.22, p = .05) but not WM-FA nor SBR (p > .1). In addition, BOLDTP (t = 2.76, p = .008) and SBR (t = -2.04, p = .04) were independently related to motor impairment (r2 = 0.18, p = .006).
Conclusion: Our findings show that brain tissue pulsatility from BOLD images in WM is related to neurological and vascular features in PD. BOLDTP may be useful in PD to study small vessel alterations that appear distinct from WM structural changes.
Keywords: Blood oxygenation level dependent MRI; Brain tissue pulsatility; Parkinson's disease; Vascular risk factors; White matter.