Research Article

Posterior Cingulate Lactate as a Metabolic Biomarker in Amnestic Mild Cognitive Impairment

Figure 2

Posterior cingulate and precuneus (PPC) MRS voxel and lac specific associations. (a) During scanning, a 4 × 4 × 4 cm voxel (shown in red) was placed bilaterally, centered on medial parietal lobe, covering the posterior cingulate, the precuneus, in most individuals the retrosplenial cortex and in a few individuals the isthmus. A large voxel size is required to provide high lac signal to noise. To ensure consistent placement across subjects, the voxel was centered along the midline, placed just anterior to the parietoccipital fissure and angled in-line with cerebellar tentorium. The voxel was toggled left-to-right to avoid as much ventricular CSF as possible. PPC lac concentrations (-axes) were correlated with performance on various neuropsychological tests including (b) memory based tasks and (c) non-memory specific tasks. Correlations were significant at (partial correlations) after correcting for age, GM, and CSF. No correlations on non-memory tasks were statistically significant.