N-acetylaspartate (NAA) peak
N-acetylaspartate (NAA) is one of the more important compounds assessed on MR spectroscopy, and resonates at 2.0 ppm chemical shift (its concentration in healthy adults is 8-10 mM) . The synthesis of NAA, adenosine diphosphate-dependent, occurs in the neuronal mitochondria.
NAA is the acetylated form of the amino acid, aspartate, which is found in high concentrations in neurons and is a marker of neuronal viability. It is therefore reduced in any process that destroys neurons, such as high grade tumors, radionecrosis, non-neuronal tumors (e.g. cerebral metastases and primary CNS lymphoma).
Markedly elevated NAA peak and NAA: creatinine ratio are pathognomonic for Canavan disease . The NAA peak level may decrease after gene therapy.
Many studies have shown the reduction of NAA, in specific brain areas, in schizophrenic patients: hippocampus, mesial regions of the temporal lobes and frontal lobes .