Multidelay multiparametric arterial spin labeling perfusion MRI and mild cognitive impairment in early stage Parkinson's disease

Abstract

Mild cognitive impairment (MCI), a well-defined nonmotor manifestation of Parkinson's disease (PD), greatly impairs functioning and quality of life. However, the contribution of cerebral perfusion, quantified by arterial spin labeling (ASL), to MCI in PD remains poorly understood. The selection of an optimal delay time is difficult for single-delay ASL, a problem which is avoided by multidelay ASL. This study uses a multidelay multiparametric ASL to investigate cerebral perfusion including cerebral blood flow (CBF) and arterial transit time (ATT) in early stage PD patients exhibiting MCI using a voxel-based brain analysis. Magnetic resonance imaging data were acquired on a 3.0 T system at rest in 39 early stage PD patients either with MCI (PD-MCI, N = 22) or with normal cognition (PD-N, N = 17), and 36 age- and gender-matched healthy controls (HCs). CBF and ATT were compared among the three groups with SPM using analysis of variance followed by post hoc analyses to define regional differences and examine their relationship to clinical data. PD-MCI showed prolonged ATT in right thalamus compared to both PD-N and HC, and in right supramarginal gyrus compared to HC. PD-N showed shorter ATT in left superior frontal cortex compared to HC. Prolonged ATT in right thalamus was negatively correlated with the category fluency test (p = .027, r = -0.495) in the PD-MCI group. This study shows that ATT may be a more sensitive marker than CBF for the MCI, and highlights the potential role of thalamus and inferior parietal region for MCI in early stage PD.

Keywords: Parkinson's disease; arterial spin labeling; arterial transit time; cerebral blood flow; mild cognitive impairment; multidelay.

Figure 1

Arterial transit time (ATT) differences among PD‐MCI, PD‐N, and HC. PD‐MCI showed prolonged ATT in right thalamus compared to both PD‐N and HC, and right SMG compared to HC. PD‐N showed shorter ATT in left superior frontal cortex compared to HC. All regions survived clusterwise correction (p < .05). Abbreviations: PD = Parkinson's disease; PD‐MCI = PD with mild cognitive impairment; PD‐N = PD with normal cognition; HC = healthy controls; L = left; R = right; SFG = superior frontal gyrus; SMG = supramarginal gyrus [Color figure can be viewed at http://wileyonlinelibrary.com]

Figure 2

Arterial transit time (ATT) differences among PD‐MCI, PD‐N, and HC compared by post hoc tests within anova. PD‐MCI showed prolonged ATT in right thalamus compared to both PD‐N and HC, and right SMG compared to HC. PD‐N showed shorter ATT in left superior frontal cortex compared to HC. Abbreviations: PD = Parkinson's disease; PD‐MCI = PD with mild cognitive impairment; PD‐N = PD with normal cognition; HC = healthy controls; L = left; R = right; SFG = superior frontal gyrus; SMG = supramarginal gurus; THA = thalamus. *p < .05 [Color figure can be viewed at http://wileyonlinelibrary.com]

Figure 3

Arterial transit time (ATT) differences between all PD patients relative to HC using two‐sample t tests. PD patients showed prolonged ATT in right SMG, right precuneus and bilateral MOG. Abbreviations: PD = Parkinson's disease; HC = healthy controls; L = left; R = right; SMG = supramarginal gyrus; MOG = middle occipital gyrus [Color figure can be viewed at http://wileyonlinelibrary.com]

Figure 4

Cerebral blood flow (CBF) differences between all PD patients relative to HC using two‐sample t tests. The CBF at 1,800 ms in right caudate and the CBF at 2,200 ms in right OFC were decreased. Abbreviations: PD = Parkinson's disease; HC = healthy controls; L = left; R = right; OFC = orbitofrontal cortex [Color figure can be viewed at http://wileyonlinelibrary.com]

Figure 5

Correlation between arterial transit time (ATT) and cognitive functions in the PD‐MCI group. Prolonged ATT in right thalamus (MNI coordinates: x = 8, y = −26, z = 2) was negatively correlated with category influence test. Abbreviations: PD = Parkinson's disease; PD‐MCI = PD with mild cognitive impairment; MNI = Montreal Neurological Institute [Color figure can be viewed at http://wileyonlinelibrary.com]