Metabolic imaging of deep brain stimulation in anorexia nervosa

Objectives Experimental data have suggested that Nucleus Accumbens (NAcc) might be a potential target for Deep Brain Stimulation (DBS) in Anorexia Nervosa (AN). But complete clinical trial results are not yet available. In this study we evaluated abnormal metabolic pattern in AN by PET to find the brain network. Then according to the network, we observed DBS treatment response to establish hypothesis of DBS mechanism in AN.

Methods 18F-FDG PET was performed on 6 AN patients and 12 age/sex-matched healthy controls (HC). Statistical parametric mapping (SPM) was used to compare metabolic differences between preoperative images in 6 AN and HC. Then 4 of the 6 AN took NAcc DBS surgery. We further compared 4 AN patients pre- and post-DBS to detect operative changes. To quantify regionally-specific metabolic changes, we constructed a 4mm radius volume of interest (VOI) within the image space, centered at the peak voxel of clusters that were significant in the unpaired and paired t-tests, respectively. We then calculated the relative glucose metabolic rates (i.e. globally normalized) in normal, Pre-Op and Post-Op PET images with the VOI option in SPM5.

Results Compared with HC, AN patients showed increases in normalized glucose metabolism in the right putamen and caudate, bilateral NAcc and hippocampus, insula (BA13)and prefrontal gyrus (BA10 and 47) and left subcallosal gyrus (BA25). DBS resulted in decreases of metabolic activity bilaterally in NAcc and hippocampus, insula (BA13) and prefrontal gyrus.

Conclusions The hypermetabolic regions revealed in this study further confirms the involvement of hedonic mechanisms in the pathophysiology of AN. DBS has restored abnormal regional metabolism within the keystones of this system. The present study verifies the potential core role of NAcc in the neurosurgical management of AN patients.

Research Support This work was supported by grants from the National Natural Science Foundation of China (81171189)