N-Acetyl Aspartate (NAA) is an amino acid found exclusively in neurons. It is regarded as a non-specific marker and is thought to be involved in Coenzyme A interactions and lipogenesis within the brain. It is a marker of neuronal viability. Normal NAA concentration is in the range of 8-9 mmol/kg in healthy adult brain. Concentrations are decreased in conditions leading to axonal injury or neuronal loss. NAA is also decreased in other conditions such as neoplasm, infarction, and inflammatory conditions such as multiple sclerosis. NAA peak is seen at 2.0 ppm (parts per million) on MR spectra.