[Fractional amplitude of low-frequency fluctuations in retinal vein occlusion: a resting-state fMRI study]

Objective: To investigate the altered spontaneous brain activity in patients with retinal vein occlusion (RVO) during the resting state. Methods: A case-control study. Forty-five patients with RVO [24 males and 21 females; age, (51.24±5.86) years] diagnosed from May 2018 to July 2019 in Renmin Hospital of Wuhan University were recruited in the RVO group. Meanwhile, forty-three healthy controls [19 males and 24 females; age, (49.79±7.31) years] who were closely matched in age and sex to patients with RVO were recruited in the healthy control group. Each subject underwent a whole-brain resting-state functional magnetic resonance imaging scan to detect the values of fractional amplitude of low-frequency fluctuations (fALFF). The altered spontaneous brain activity between RVO patients and healthy controls were analyzed. The intra-and inter-group comparisons of two sets of fALFF values were conducted using one-sample t-test and two-sample t-test, respectively. Results: Compared with the healthy control group, the fALFF values of RVO patients were significantly changed. The fALFF values of left cerebellum (-0.68±0.48, t=3.8081), right cerebellum (-0.79±0.47, t=4.590), right brainstem (-0.57±0.50, t=3.964) and left insula (-0.22±0.27, t=3.587) increased, while the fALFF values of right calcarinesulcus (0.60±0.72, t=-3.521), right thalamus (-0.68±0.43, t=-3.846) and left lingual gyrus (-0.12±0.33, t=-3.876) decreased. The differences were statistically significant (voxel-level P<0.01, Gaussian random field correction, cluster-level P<0.05). Conclusions: Patients with RVO have abnormal spontaneous neural activity in multiple brain areas, including visual pathways and emotion-cognition processing regions. Moreover, there may be compensatory brain function enhancement in local brain areas. The results provide new insights into the understanding of the mechanism for the occurrence and development of RVO.(Chin J Ophthalmol, 2020, 56:266-271).