Resting-state Regional Cerebral Blood Flow Alterations in Macrovasculature and Microvasculature in Parkinson’s Disease: A Systematic Review and Meta-analysis
Melanie Pitzer1, Sriya Avadhanam2, Hamidreza Ghodsi1, Amin Saberi3, Katherine Longadner1
1Parkinson and Other Movement Disorders Center, University of California San Diego, 2Tufts University School of Medicine, 3Institute of Neurosciences and Medicine (INM-7), Research Centre Jülich
Objective:
To assess changes in resting-state cerebral blood flow (CBF) across various brain regions and CBF velocity (CBFv) of the middle cerebral artery (MCA) in Parkinson’s disease (PD) compared to healthy controls (HC).
Background:
PD manifests with dopaminergic and cholinergic neuronal loss, leading to decreased ability to modulate vascular tone, cerebral perfusion, and metabolic activity. Several studies have shown decreased CBF in the microvasculature of various brain regions in PD, while others found no changes. Additionally, cerebral autoregulation of large vessels is essential to maintain perfusion under various physiologic conditions, but whether CBFv is altered in PD remains controversial.
Design/Methods:
We searched the literature for studies measuring resting-state CBF in PD patients and HC using modalities including transcranial Doppler (TCD), arterial spin labeling (ASL)-MRI, SPECT, and PET. Quantitative and semi-quantitative CBF and CBFv values were converted to standardized mean differences (SMDs) and were pooled using a random-effects meta-analysis.
Results:
In total, 117 studies involving 1820 PD patients and 1288 HCs were included. CBF was reduced in the whole brain (SMD = -0.76 (-1.40, -0.11), P = 0.024), cortex (SMD = -0.59 (-0.92, -0.26), P = 0.006), and grey matter (SMD = -0.36 (-0.65 to -0.06), P = 0.026). Decreased CBF was also observed in the temporal (SMD = -0.93), parietal (SMD = -0.90), occipital (SMD = -0.63), and frontal (SMD = -0.58) lobes, as well as the caudate nucleus (SMD = -0.69) and thalamus (SMD = -0.23). The subthalamic nucleus was the only region showing increased CBF (SMD = 0.74). CBFv in the MCA was decreased in PD (SMD = -0.65 (9-1.13, -0.16), P = 0.013).
Conclusions:
Resting-state CBF in microvasculature is significantly reduced in PD across the whole brain, cortex, and grey matter, particularly in temporal, parietal, and occipital regions. Additionally, CBFv through the MCA is also decreased.
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.