N-acetylaspartate (NAA) peak

Last revised by Andrew Murphy on 2 Apr 2020

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) 1. The synthesis of NAA, adenosine diphosphate-dependent, occurs in the neuronal mitochondria 2.

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 7. 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 3-6.

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