Resting-state functional magnetic resonance imaging of patients with obsessive-compulsive disorder based on amplitude of low-frequency fluctuation

Objective To analyze the altered amplitude of low-frequency fluctuation (ALFF) and fraction ALFF (fALFF) in patients with obsessive-compulsive disorder (OCD) using resting-state functional magnetic resonance imaging (RS-fMRI). Methods Twenty-seven un-medicated patients with OCD and 29 healthy age-, gender-and education level-matched volunteers, collected in our hospital from January 2013 to December 2014, underwent RS-fMRI. An approach of ALFF and fALFF was used to compare resting-state activity between the two groups. Subsequently, correlation analysis was performed between ALFF and fALFF values in significantly altered brain regions and Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores of the OCD patients. Results As compared with healthy volunteers, the OCD patients had significantly reduced ALFF values in the right precuneus, and significantly reduced fALFF values in the right precuneus and the left middle temporal gyrus (P<0.05). The ALFF values and fALFF values in the right precuneus and the fALFF values in left middle temporal gyrus had no significant correlation with Y-BOCS scores of the OCD patients (r=-0.130, P=0.518; r=-0.270, P=0.173; r=-0.041, P=0.839). Conclusion ALFF and fALFF changes in the right precuneus and fALFF changes in the left middle temporal gyrus are associated with pathophysiology mechanism of OCD, and these values is not correlate with symptom severity of OCD. Key words: Obsessive-compulsive disorder; Resting-state functional magnetic resonance imaging; Amplitude of low-frequency fluctuation; Fractional amplitude of low-frequency fluctuation