The study of brain temperature is important for a number of clinical conditions
such as stroke, traumatic brain injury, schizophrenia and birth asphyxia (for
neonates). A direct method to estimate brain temperature non-invasively will
allow assessment of brain thermoregulation and its variation in clinical
conditions.
Magnetic resonance imaging is a powerful technique widely used for
diagnosis of a range of neurological conditions. All magnetic resonance
procedures involve manipulation of the hydrogen nuclei in the water
molecules of the human body. The resonance frequency of the water
molecules is temperature dependent, thus MR thermometry is a powerful tool
for non-invasive temperature measurement. Using internal reference MR
spectroscopic imaging (MRSI), absolute brain temperature maps can be
estimated. However a number of temperature independent factors influence
MRSI data acquisition, thus a thorough validation is necessary and is the
focus of this PhD study.
In this PhD study using phantom (test object) studies it was shown that
optimization of the MRSI pulse sequence is necessary to reduce systematic
error in temperature maps and extensive in-vitro validation of MRSI
temperature mapping was performed. A custom made temperature-controlled
phantom was designed for this purpose and is presented in this
thesis. MRSI data acquired from healthy (young and elderly) volunteers was
employed to assess regional brain temperature variations and repeatability.
Finally, the feasibility of employing fast echo planar spectroscopic imaging for
volumetric MRSI temperature mapping will be presented in this thesis