Study serotonergic alteration in obsessive-compulsive-disorder (OCD) patients: PET imaging using C-11 DASB, a serotonin transporter (SERT) ligand

Abstract

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Objectives: SERT is implicated in the pathogenesis of OCD. Herein, we assessed the potential of C-11 DASB in identifying SERT abnormalities in OCD and compared distribution pattern of C-11 DASB in OCD subjects to age matched healthy controls (control).

Methods: 8 controls and 4 OCD subjects were enrolled using DSM-IV criteria, Y-BOCS, HAM-A, and HAM-D Inventories. Each subject underwent MRI followed i.v. injection of C-11 DASB for PET scan. Binding potential (BP_ND) were derived using Gunn method (P-MOD) and cerebellum as reference region.

Results: C-11 DASB was prepared in 35 ± 12% RCY (Sp. Act. 6866 ± 3740 mCi/µmole). Whole brain BP_ND was 0.141 ± 0.006 for controls and 0.115 ± 0.014 for the OCD subjects (18% ↓ in OCD). In control group, the BP_ND in caudate, thalamus, cingulate cortex, and amygdala were 1.11 ± 0.04, 1.30 ± 0.03, 0.24 ± 0.01, and 0.68 ± 0.04, respectively. BP_ND increased in OCD subjects by 7%, 6%, and 16% in caudate, thalamus, cingulate cortex, respectively. In contrast, BP_ND was significantly low (22% ↓) for amygdala in OCD (p<0.05). Significant finding of this study was a distinctly different accumulation pattern of DASB in OCD than in the controls.

Conclusions: These preliminary findings in limited number of subjects demonstrate that DASB is a useful ligand to quantify SERT alterations in OCD. Additional studies are neccessary to further strengthen the potential of DASB to study OCD pathogenesis.

Research Support: Pilot study grant (WFU Center for Biomolecular Imaging).