HISTOLOGICAL AND H-1 MAGNETIC-RESONANCE SPECTROSCOPIC IMAGING ANALYSIS OF QUINOLINIC ACID-INDUCED DAMAGE TO THE RAT STRIATUM

NAA has been described as a neuron-specific compound. NAA levels as de termined by magnetic resonance spectroscopic imaging (MRSI) have been used to determine degree of neuronal loss in several neurological dise ases, but there has been limited work to document the accuracy and rel iability of this technique. This study addresses this question quantit atively with histological analysis of cell viability and tissue shrink age in quinolinic acid (QA)-induced damage of the rat striatum compare d with H-1 MRSI measurement of N-acetyl aspartate (NAA) as a noninvasi ve measure of neuronal loss. Both H-1 MRSI and histology detect damage to the lesioned striatum; however, there are differences in the degre e of damage as assessed by the two methods. Although partial-volume ef fects and tissue shrinkage may decrease the sensitivity of MR to such damage, the sparing of axons by QA may be another important factor in the differences in assessment. These results indicate that further stu dies of NAA metabolism and its distribution within neurons are warrant ed.