Dopamine Transporter Density of the Basal Ganglia Assessed with I-123 IPT SPECT in Patients with Obsessive-Compulsive Disorder

Kim, Chan Hyung; Koo, Min Seong; Cheon, Keun Ah; Ryu, Young Hoon; Lee, Jong Doo

Abstract

OBJECTIVES
It has been suggested that dopamine as well as serotonin were related to the pathophysiology of obsessive-compulsive disorder (OCD). Thus, many studies were performed to nivestigate brain regions and their association with dopamine in OCD patients. Recently, we have been able to monitor the density of the dopamine transporter (DAT) in the basal ganglia using I-123N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane (I-123 IPT) SPECT, to evaluate the activity of the presynaptic dopamine function. In present study, we investigated the DAT density of the basal ganglia using I-123 IPT SPECT in patients with OCD.
METHODS
Fifteen patients with OCD and nineteen normal control group were included in this study. We performed brain SPECT 2 hours after the intravenous administration of I-123N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane (I-123 IPT) and carried out both quantitative and qualitative analyses using the SPECT, which were reconstructed for the assessment of the specific/nonspecific DAT binding ratio in basal ganglia. We then investigated the correlation between the severity of OCD symptoms assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the specific/nonspecific DAT binding ratio of basal ganglia.
RESULTS
Patients with OCD showed a significantly increased specific/nonspecific DAT binding ratio in right basal ganglia compared with normal controls and did not show a significantly increased specific/nonspecific DAT binding ratio, and an increased tendency in the specific/nonspecific DAT binding ratio in left basal ganglia (Rt:Z=2.584, P=0.009, Lt:=1.873, P=0.060). We found no significant correlation between the total scores of the Y-BOCS and the specific/nonspecific DAT binding ratio of basal ganglia.
CONCLUSIONS
The data of this study suggest that dopamine in basal ganglia plays an important role in fronto-subcortical circuit, which are already known as a site of the pathophysiological mechanism of OCD.