title: Feasibility of internally referenced brain temperature imaging with a metabolite signal.
abstract: 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.
authors.affiliation: Department of Image-Based Medicine, Institute of Biomedical Research and Innovation, Kobe, Japan. kuroda@ibri-kobe.org
authors.forename: Kagayaki
authors.initials: K
authors.lastname: Kuroda
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Takei
authors.forename: Robert V
authors.initials: RV
authors.lastname: Mulkern
authors.forename: Koichi
authors.initials: K
authors.lastname: Oshio
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Nakai
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Okada
authors.forename: Akira
authors.initials: A
authors.lastname: Matsumura
authors.forename: Kiyoyuki
authors.initials: K
authors.lastname: Yanaka
authors.forename: Kullervo
authors.initials: K
authors.lastname: Hynynen
authors.forename: Ferenc A
authors.initials: FA
authors.lastname: Jolesz
mesh_terms: 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
chemical_list: D011522:Protons; D001224:Aspartic Acid; C000179:N-acetylaspartate