Document 14776038

AbstractID: 7275 Title: Correlation of myelination determination by magnetization transfer imaging and
proton spectroscopy in the developing brain
The development of cognitive and motor skills in children is an area of intense
interdisciplinary research where the knowledge of the structure and function of the brain
is integrated. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy
(MRS) provide anatomical and functional information and thus has the potential to study
brain maturation in vivo. One such aspect of brain maturation that has been studied by
MRI and MRS is the myelination process. The creation of myelin in the different regions
of the brain occurs in a defined temporal sequence. Magnetization transfer (MT) contrast
in a MR image is based on the exchange of magnetization between protons bound to
macromolecules and the relatively free protons of water in the tissue. Since the
cholesterol component of myelin has significant MT effect, images modulated by MT
contrast have been used to derive magnetization transfer ratio (MTR) to quantitate the
myelination process. In MRS, the ability to obtain the quantitative distribution of cerebral
metabolites is exploited to study the maturing brain. Since N-acetylaspartate (NAA) is
considered a neuronal marker, its concentration should correlate to the neuronal
development and maturation of the brain. In this study the literature data for MTR and
NAA concentrations are compared for ages from birth to one hundred months. Both the
variables show the predictable exponential increase with age, reaching a plateau after
twenty-four months. The rates of increase seem to be different, perhaps implying
different quantitative relationships of the two signals to the myelination process.