Disrupted Regional Cerebral Blood Flow and Functional Connectivity in Pontine Infarction: A Longitudinal MRI Study.

Ying Wei,Caihong Wang,Kaiyu Wang,Luobing Wu,Jingliang Cheng,Jingchun Liu,Peifang Miao,Yingying Wang

doi:10.3389/fnagi.2020.577899

Abstract

Abnormal cerebral blood flow (CBF) and resting-state functional connectivity (rs-FC) are sensitive biomarkers of disease progression and prognosis. This study investigated neural underpinnings of motor and cognitive recovery by longitudinally studying the changes of CBF and FC in pontine infarction (PI). Twenty patients underwent three-dimensional pseudo-continuous arterial spin labeling (3D-pcASL), resting-state functional magnetic resonance imaging (rs-fMRI) scans, and behavioral assessments at 1 week, 1, 3, and 6 months after stroke. Twenty normal control (NC) subjects underwent the same examination once. First, we investigated CBF changes in the acute stage, and longitudinal changes from 1 week to 6 months after PI. Brain regions with longitudinal CBF changes were then used as seeds to investigate longitudinal FC alterations during the follow-up period. Compared with NC, patients in the left PI (LPI) and right PI (RPI) groups showed significant CBF alterations in the bilateral cerebellum and some supratentorial brain regions at the baseline stage. Longitudinal analysis revealed that altered CBF values in the right supramarginal (SMG_R) for the LPI group, while the RPI group showed significantly dynamic changes of CBF in the left calcarine sulcus (CAL_L), middle occipital gyrus (MOG_L), and right supplementary motor area (SMA_R). Using the SMG_R as the seed in the LPI group, FC changes were found in the MOG_L, middle temporal gyrus (MTG_L), and prefrontal lobe (IFG_L). Correlation analysis showed that longitudinal CBF changes in the SMG_R and FC values between the SMG_R and MOG_L were associated with motor and memory scores in the LPI group, and longitudinal CBF changes in the CAL_L and SMA_R were related to memory and motor recovery in the RPI group. These longitudinal CBF and accompany FC alterations may provide insights into the neural mechanism underlying functional recovery after PI, including that of motor and cognitive functions.

Highlights

Pontine infarction (PI) accounts for 7% of ischemic strokes and is the most common type of posterior circulation infarction (Wang et al, 2018)
There was no significant difference among different subgroups in mean framewise displacement (FD) values (PLPI = 0.349, PRPI = 0.864)
By combining pcASL and resting-state functional magnetic resonance imaging (rs-functional magnetic resonance imaging (fMRI)), we investigated the longitudinal changes in cerebral blood flow (CBF) and functional connectivity (FC) during the 6 month follow-up period

Summary

INTRODUCTION

Pontine infarction (PI) accounts for 7% of ischemic strokes and is the most common type of posterior circulation infarction (Wang et al, 2018). Some researchers have investigated CBF patterns of chronic PI by using ASL and have found that patients with PI showed higher CBF values in the contralateral inferior frontal gyrus and lower CBF values in the bilateral cerebellum; the CBF values in the contralateral cerebellum were closely associated with motor function scores (Wang et al, 2019). Early evidence has utilized FC to investigate the neural mechanisms underlying stroke-related behavioral function decline, there is little knowledge about PI, especially longitudinal and within-person changes. Based on the abovementioned knowledge, in order to explore the neural substrates of functional recovery after PI, we first investigated the cross-sectional and longitudinal changes in CBF during the 6 months following PI. We further investigated the relationships among abnormal changes in CBF, FC, and behavioral performance after stroke

Participants

RESULTS

DISCUSSION

ETHICS STATEMENT