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bioRxiv · 10.1101/281352

Physiological Significance of R-fMRI Indices in Detecting Structural Brain Lesions

Fan, Z.·Chen, X.·Qi, Z.-X.·Li, L.·Lu, B.·Jiang, C.-L.·Zhu, R.-Q.·Chen, L.·Yan, C.-G.
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Abstract

Resting-state functional MRI (R-fMRI) research has recently entered the era of \"big data\", however, few studies have provided a rigorous validation of the physiological underpinnings of R-fMRI indices. Although studies have reported that various neuropsychiatric disorders exhibit abnormalities in R-fMRI measures, these \"biomarkers\" have not been validated in differentiating structural lesions (brain tumors) as a concept proof. We enrolled 60 patients with intracranial tumors located in the unilateral cranial cavity and 60 matched normal controls to test whether R-fMRI indices can differentiate tumors, which represents a prerequisite for adapting such indices as biomarkers for neuropsychiatric disorders. Common R-fMRI indices of tumors and their counterpart control regions, which were defined as the contralateral normal areas (for amplitude of low frequency fluctuations (ALFF), fractional ALFF (fALFF), regional homogeneity (ReHo) and degree centrality (DC)) and ipsilateral regions surrounding the tumors (for voxel-mirrored homotopic connectivity (VMHC)), were comprehensively assessed. According to paired t-tests with a Bonferroni correction, only ALFF (both with and without Z-standardization) and VMHC (Fishers r-to-z transformed) could successfully differentiate substantial tumors from their counterpart normal regions in patients. And DC was not able to differentiate tumor from normal unless employed Z-standardization. To validate the lower power in the between-subject design than in the within-subject design, each metric was calculated in a matched control group, and two-sample t-tests were used to compare the patient tumors and the normal controls at the same area. Only ALFF (and that with Z-standardization) along with VMHC succeeded in differentiating significant differences between tumors and the sham tumors areas of normal controls. This study tested the premise of R-fMRI biomarkers for differentiating lesions, and brings a new understanding to physical significance of the Z-standardization.

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Fan, Z., Chen, X., Qi, Z.-X., Li, L., Lu, B., Jiang, C.-L., Zhu, R.-Q., Chen, L., Yan, C.-G.. 2018-03-13. Physiological Significance of R-fMRI Indices in Detecting Structural Brain Lesions. https://doi.org/10.1101/281352

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