Wen-Ching Liu1, Timothy Linghau Chen2, Kyler Shin2, and David Wang3
1Radiology, OSF Saint Francis Medical Center, Peoria, IL, United States, 2Medicine, University of Illinois College of Medicine at Peoria, Peoria, IL, United States, 3Neurology, Barrow's Neurological Institute, Phoenix, AZ, United States
Synopsis
In order to establish the standard brain regional temperatures in normal and healthy people, we initiated a weekly MR spectroscopy quality assurance program, developed the single voxel MRS thermometry calibration curve with a MRS phantom and scanned 10 normal and healthy right handed men. Five region of interests, hypothalamus, cerebellum, thalamus, frontal lobe, and occipital lobe are selected. Interestingly we found a non-uniform temperature distribution in these ROIs. The hypothalamus and thalamus have the highest temperature while cerebellum has the lowest.
Introduction
MR Thermometry has been demonstrated feasible in measuring human
brain temperature (1). In our
institution, we want to develop a hypothermia program for stroke patient using MR
Thermometry. However, up to date, there
is no standard brain temperature available. The purpose of this study is to
establish the brain temperatures in five specific locations: hypothalamus, Cerebellum,
Thalamus, Frontal Lobe, and Occipital Lobe among health men.
These five areas will generally cover most of the brain temperature
distribution. We use proton resonance
frequency -MR spectroscopy (PRF-MRS) single voxel method (2) since it can
provide us an absolute temperature for the region of interest (ROI). Methods
The study utilizes a GE 3T Discovery MR scanner. A weekly MR Spectroscopy quality assurance (QA)
program, in which the same GE MRS phantom (BRANO) will be scanned, is integrated to
monitor the scanner’s performance. A
PRF-MRS chemical shift vs temperature relationship was established using a
BRANO phantom by repeatedly scan a heated phantom from 45 degree C to around 30
degree C. Ten normal and healthy, right
handed, adult men ages between 20-60 were imaged in the morning using single
voxel Probe-p, which is the PRESS sequence with the parameters of TR/TE=1500/144, voxel
size 2x2x2 cm, and 8 next. The MRS data
were first processed using Tarquin (3) and the chemical shift differences between
N-Acetylasparte (NAA) peak and water peak were obtained. This chemical shift difference was mapped to the temperature calibration curve to generate the corresponding temperature. Temperature from five ROIs of each subject were
obtained and a mean and standard deviation were calculated. Results
The weekly QA program indicated that the scanner has a
linewidth of 2Hz consistently. The chemical
shift-temperature calibration curve is
T(C) = -107.27 x (δ_w-naa) +321.57 Eq [1]
where δ_w-naa (ppm) is the chemical shift differences between water peak and NAA peak.
The temperature calculated from this equation are within
1-5% variations when compared with other published data (4,5).
The average temperature for each ROI is the following, 39.71±2.94 (Hypothalamus), 37.01±1.98 (cerebellum), 39.22±1.37
(Thalamus), 38.05 ± 1.83 (Frontal lobe) and 37.29±1.26 (Occipital lobe). Conclusion
We believe that it is the first study to report brain regional temperatures in healthy subjects. It is also
interesting to find out that cerebellum has the lowest and hypothalamus and
thalamus have the highest temperatures in the brain region. Acknowledgements
No acknowledgement found.References
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