Figure 8:

Age-associated MM differences. Average metabolite-nulled macromolecular spectra measured from four young adults (26 ± 4 years) and three older adults (73 ± 3 years) normalized to water reference and taking into consideration GM, WM and cerebrospinal fluid content, as well as T₂ of water in different compartments. Clear age-associated differences in MM pattern are apparent, as the spectra overlap completely at 0.9 ppm, but diverge at several other chemical shifts. A content difference is also apparent, as the spectra are normalized, and the MM spectrum for young adults lies below the MM spectrum for older adults to a greater extent in the 1–2.3 ppm range than it lies above the MM spectrum for older adults in the 3–4.5 ppm range. Adapted from reference⁶⁴ with permission. 7 T, single inversion recovery technique combined with STEAM, TR = 2 s, TE = 8 ms, TM = 32 ms, TI = 0.68 s, 8-mL volume of interest in the occipital cortex, 1664 averages for the young adults, 960 averages for the older adults.