Test-retest stability analysis of resting brain activity revealed by blood oxygen level-dependent functional MRI

Purpose: To assess testretest stability of four functional magnetic resonance imaging (fMRI)-derived resting brain activity metrics: the seed-region-based functional connectivity (SRFC), independent component analysis (ICA)-derived network-based FC (NTFC), regional homogeneity (ReHo), and the amplitude of low frequency fluctuation (ALFF). Methods: Simulations were used to assess the sensitivity of SRFC, ReHo, and ALFF to noise interference. Repeat resting blood oxygen level-dependent (BOLD) fMRI were acquired from 32 healthy subjects. The intraclass correlation coefficient (ICC) was used to assess the stability of the four metrics. Results: Random noise yielded small random SRFC, small but consistent ReHo and ALFF. A neighborhood size greater than 20 voxels should be used for calculating ReHo in order to reduce the noise interference. Both the anterior cingulate cortex (ACC) and posterior cingulate cortex (PCC)-based SRFC were reproducible in more spatially extended regions than ICA NTFC. The two regional spontaneous brain activity (SBA) measures, ReHo and ALFF, showed testretest reproducibility in almost the whole gray matter. Conclusion: SRFC, ReHo, and ALFF are robust to random noise interference. The neighborhood size for calculating ReHo should be larger than 20 voxels. ICC > 0.5 and cluster size > 11 should be used to assess the ICC maps for ACC/PCC SRFC, ReHo, and ALFF. BOLD fMRI-based SBA can be reliably measured using ACC/PCC SRFC, ReHo, and ALFF after 2 months. J. Magn. Reson. Imaging 2012;36:344354. (c) 2012 Wiley Periodicals, Inc.