McLean Imaging Center, McLean Hospital, Belmont, Massachusetts.
Harvard Medical School, Boston, Massachusetts.
Magn Reson Med. 2019 May;81(5):2896-2904. doi: 10.1002/mrm.27635. Epub 2019 Jan 16.
To evaluate brain temperature effects of early simian immunodeficiency virus (SIV) infection in rhesus macaques using proton magnetic resonance spectroscopy (MRS) thermometry (MRSt) and to determine whether temperature correlates with brain choline or myo-inositol levels.
Brain temperature was retrospectively determined in serial MRS scans that had been acquired at baseline and at 2 and 4 weeks post-SIV infection (wpi) in 16 monkeys by calculating the chemical shift difference between N-acetylaspartate (NAA) and water peaks in sequentially acquired water-suppressed and unsuppressed point-resolved spectroscopy (PRESS) spectra. Frontal and parietal cortex, basal ganglia, and white matter spectra were analyzed.
At 2 wpi, brain and rectal temperatures increased relative to baseline and normalized at 4 wpi. Brain temperatures correlated with choline levels in several brain areas, but not with myo-inositol levels.
These data indicate that SIV transiently increases brain temperature soon after infection and that temperature is correlated with transient changes in choline levels. Given that choline levels are associated with brain inflammation in SIV-infected monkeys, our findings suggest that the SIV-induced temperature increase reflects brain inflammation. We conclude that MRSt may be informative in human immunodeficiency virus models and may be useful for assessing effects of treatments that reduce inflammation. This study also illustrates that existing MRS data sets containing unsuppressed water spectra can be used to measure tissue temperature, an important physiological parameter.
使用质子磁共振波谱（MRS）测温法（MRSt）评估恒河猴早期感染猴免疫缺陷病毒（SIV）时的大脑温度效应，并确定温度是否与脑内胆碱或肌醇水平相关。
通过计算依次采集的水抑制和未抑制点分辨波谱（PRESS）谱中 N-乙酰天冬氨酸（NAA）和水峰之间的化学位移差， retrospectively 确定了 16 只猴子在基线和感染 SIV 后 2 周和 4 周（wpi）进行的一系列 MRS 扫描中的大脑温度。分析了额叶和顶叶皮层、基底节和白质的光谱。
在 2 wpi 时，大脑和直肠温度相对于基线升高，并在 4 wpi 时恢复正常。大脑温度与几个大脑区域的胆碱水平相关，但与肌醇水平不相关。
这些数据表明，SIV 感染后不久会短暂增加大脑温度，并且温度与胆碱水平的短暂变化相关。鉴于胆碱水平与 SIV 感染猴子的大脑炎症有关，我们的发现表明 SIV 引起的温度升高反映了大脑炎症。我们得出结论，MRSt 可能对人类免疫缺陷病毒模型具有信息性，并且可能有助于评估降低炎症的治疗方法的效果。本研究还表明，包含未抑制水谱的现有 MRS 数据集可用于测量组织温度，这是一个重要的生理参数。
