A resting-state fMRI cross-sectional study of CRF decline after stroke

Abstract

Abstract Objective To analyze the changes of neural activity intensity and brain functional network in brain functional areas after the decrease of CRF in stroke patients by using resting-state fMRI, so as to find the possible brain areas of CRF in stroke patients. Methods Twenty-two stroke patients were recruited according to the inclusion criteria of the study, and 15 age -, gender - and BMI - matched healthy control were recruited. Both stroke patients and healthy control underwent behavioral assessment and resting-state fMRI scan. Rehabilitation assessments included peak oxygen consumption (VO2peak), peak work-rate, 10-meter walk test (10mWT), five times sit-to-stand test (FTSST), and 6-minute walk test (6MWT). The resting-state fMRI data of the two groups were collected, and the correlation between the changes of amplitude of low frequency fluctuations (ALFF) and CRF was analyzed to find out the brain regions related to CRF and local neural activity in stroke patients. On the basis of ALFF analysis, the brain network analysis was carried out, and the CRF related brain regions of stroke patients were selected as seed points. Through functional connectivity analysis, the CRF and brain network related brain regions of stroke patients were found out. Results VO2peak, Work-rate peak, 10mWT and 6MWD in stroke patients were significantly lower than those in healthy control (P<0.001). FTSST in stroke patients was significantly higher than that in healthy control (P<0.001). ALFF analysis showed that the brain regions related to CRF in stroke patients were the ipsilesional superior temporal gyrus (r=0.5826, P=0.0002), the middle frontal gyrus (r=0.6340, P<0.0001) and the precentral gyrus (r=0.5895, P=0.0001). Functional connectivity analysis showed that the functional connectivity of brain regions related to CRF in stroke patients was from ipsilesional M1 to ipsilesional precentral gyrus and contralesional postcentral gyrus, and the correlation coefficients were (r=0.5263, P=0.0008) and (r=0.4595, P=0.0042), respectively. The correlation coefficients of ipsilesional middle frontal gyrus to contralesional middle frontal gyrus, angular gyrus and ipsilesional superior frontal gyrus were (r=0.5509, P=0.0004), (r=0.5192, P=0.001) and (r=-0.666, P<0.001), respectively. Conclusion The CRF, peak work-rate, 10-meter walk test and 6-minute walk distance of the stroke subjects were lower than those of the healthy control, while the five times sit-to-stand test was the opposite, which verified the fact that CRF would decrease after stroke. The resting-state fMRI index ALFF analysis showed that the relevant brain regions of CRF and local neural activity in stroke patients were the ipsilesional superior temporal gyrus, middle frontal gyrus and precentral gyrus. The FC showed that the relevant brain regions of CRF and brain network in stroke patients were ipsilesional M1 to ipsilesional precentral gyrus and contralesional postcentral gyrus, ipsilesional middle frontal gyrus to contralesional middle frontal gyrus, angular gyrus and ipsilesional superior frontal gyrus.