Effect Of Deep Brain Stimulation On The Brain Metabolic Pattern In Patients With Depression: Comparison Of Pre And Post Therapy Pet/Ct Scans-A Pilot Study.

489 Objectives: To determine any changes in the cerebral metabolism pattern on the pre and post therapy 18F-fluoro-deoxyglucose-positron emission tomography in patients undergoing Deep Brain Stimulation (DBS) for resistant depression. Methods: This is a Pilot study which included patients, who underwent pre and post DBS PET-CT brain imaging between January, 2015 and December, 2018. All the patients underwent pre DBS PET/CT studies. Subsequently after undergoing the DBS each patient underwent one year follow up PET/CT study except one patient who had a 8 month follow up imaging. All PET-CT scans were interpreted by 2 experienced nuclear medicine physicians. Each PET/CT study was also analyzed quantitatively using the MIM neuroanalysis software and Z scores were generated comparing the areas of metabolism in the patients with the age matched normal population. Patient’s demographic, clinical data and imaging results were collected and analyzed. Results: Nine patients were included, 5 females and 4 males with mean age of 53.1 years. The pre- therapy PET/CT on visual analysis demonstrated decreased metabolism in the temporal lobes in 3 patients (33%), in the frontal lobes in 3 patients (33%) and 2 patients (22%) showed hypometabolism in both frontal and temporal lobes. One patient had normal metabolism visually. The quantitative neuroanalysis is shown in the table below. (The Z scores represent standard deviation from normal age matched population and are significant if below -1.6). The visual findings remained unchanged in the subsequent post DBS PET/CT studies. Mild improvement in the Z scores in different regions including medial temporal lobe, inferior frontal gyrus, parahippocampal gyrus, superior medial frontal gyrus and posterior cingulate, caudate lobe and Amygdala was noted in 5 patients. Clinically all patients demonstrated significant symptomatic improvement. These patients reported feelings of energy and motivation concordant with mood improvement. Conclusions: Despite significant symptomatic clinical improvement in patients with resistant depression after DBS, there was no significant change in the brain metabolic findings using FDG PET/CT. Additionally, different areas of the brain demonstrated minimal improvement in quantitative analysis.