A 1HMRS study of the anterior cingulate gyrus in euthymic bipolar patients

Introduction The anterior cingulate region has been implicated in the pathophysiology of mood disorders. Studies have reported anatomical and functional abnormalities in this region in bipolar disorder patients. Few neurochemical studies have evaluated this region, especially on medicated bipolar patients. Lithium has been reported to increase NAA levels but not by all studies. We used proton magnetic spectroscopy (HMRS) to measure the levels of N-acetyl-L-aspartate (NAA) and choline (Cho) relative to creatine (Cr) in the anterior cingulate of euthymic medicated bipolar subjects. Methods (HMRS)-H-1 was performed using a GE Signa 1.5 Tesla scanner in 13 euthymic bipolar patients who were taking lithium for at least four weeks before the scan and in 15 normal controls. The 1HMRS signal was collected from an 8 cm voxel placed in the anterior cingulate. Data analysis was performed with the automated PROBE/SV quantification tool. Results NAA/Cr and Cho/Cr ratios were not significantly different between patients and controls (NAA/Cr: 1.60 +/- 0.34 in patients, 1.68 +/- 0.34 in controls; Cho/Cr: 1.13 +/- 0.13 in patients, 1.11 +/- 0.20 in controls). Conclusions We did not find a significant difference in the NAA/Cr and Cho/Cr ratio between bipolar patients and healthy controls. Chronic administration of psychotropic drugs could have had an effect on NAA/Cr levels of bipolar patients. Copyright (c) 2006 John Wiley & Sons, Ltd.