Feasibility of internally referenced brain temperature imaging with a metabolite signal.
The feasibility of using a metabolite signal as an internal reference for self-referenced temperature distribution measurement was examined. Line scan echo-planar spectroscopic imaging (LSEPSI) was applied to obtain quick multi-voxel spectroscopic measurements and to avoid possible spectral degradation from motion. Temperature distribution in a rabbit brain in vivo was successfully visualized by means of the chemical shift of water, which was measured by using naturally abundant (up to 10 mM) N-acetyl-aspartate (NAA) as the reference signal. Unlike the phase-mapping approach, this technique does not require a pixel-by-pixel subtraction. Therefore, in theory, it is more resistant to inter-scan motion or changes in susceptibility. The spatial and temporal resolutions of this technique are 1.5 cm3 and 4.5 min. A higher signal-to-noise ratio and optimization of the water and outer-volume suppression capabilities will be required to further enhance the temperature-mapping capabilities.
Kuroda
Kagayaki
K
Department of Image-Based Medicine, Institute of Biomedical Research and Innovation, Kobe, Japan. kuroda@ibri-kobe.org
Takei
Naoyuki
N
Mulkern
Robert V
RV
Oshio
Koichi
K
Nakai
Toshiharu
T
Okada
Tomohisa
T
Matsumura
Akira
A
Yanaka
Kiyoyuki
K
Hynynen
Kullervo
K
Jolesz
Ferenc A
FA
D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001831:Body Temperature; D001834:Body Water; D001921:Brain / Q000378:metabolism*; D017352:Echo-Planar Imaging / Q000379:methods*; D005240:Feasibility Studies; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D019047:Phantoms, Imaging; D011522:Protons; D011817:Rabbits; D013997:Time Factors
D011522:Protons; D001224:Aspartic Acid; C000179:N-acetylaspartate