Multi-modal imaging study of striatal dopamine D2 receptors binding potential and brain regional homogeneity in patients with first-episode major depressive disorder

Objective To explore the correlation between changes of striatal dopamine D2 receptors non-displaceable binding potential (BPND) in 11C-Raclopride PET-CT and brain regional homogeneity (ReHo) derived from resting state functional MRI (fMRI) in patients with first-episode major depressive disorder (MDD). Methods Patients with first-episode MDD and age and sex matched healthy volunteers accepted brain 11C-Raclopride PET-CT and resting state fMRI. MIAKAT based on MATLAB and Rest 1.8 were used to calculate BPND of brain dopamine D2 receptors and brain ReHo, respectively. Changes of striatal dopamine D2 receptors BPND and brain ReHo values were analyzed by paired-sample t test and two independent sample t-test, and Pearson correlation analysis was used to analyze the correlation between BPND and ReHo. Results Twenty patients with first-episode MDD were enrolled as MDD group, and 20 healthy volunteers as the control group. The two groups were all right-handed, and there were no statistical differences for age (t=1.33, P=0.19) and gender (χ2=0.10, P=0.75). Compared with the control group, the ReHo in MDD patients increased in the bilateral striatum (caudate nucleus and putamen), bilateral medial prefrontal lobes, and right thalamic (27 to 56 voxels, P 0.05). Conclusion There were abnormal levels of dopamine neurotransmitter in the cerebral striatum regions and abnormal brain activities in the brain region associated with dopamine reward circuit in the first-episode MDD patients, and there was a correlation between the two abnormalities. Key words: Depressive disorder; Magnetic resonance imaging; Positron-emission tomography; Tomography, X-ray computed