Kuriyama Nagato, Yamada Kei, Sakai Koji, Tokuda Takahiko, Akazawa Kentaro, Tomii Yasuhiro, Tamura Aiko, Kondo Masaki, Watanabe Isao, Ozaki Etsuko, Matsui Daisuke, Nakagawa Masanori, Mizuno Toshiki, Watanabe Yoshiyuki
Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine.
Magn Reson Med Sci. 2015;14(4):305-12. doi: 10.2463/mrms.2014-0076. Epub 2015 Jun 23.
The brain produces intense heat as a result of cerebral metabolism and cerebral blood flow, and the generated heat is removed mainly through circulation of the intracranial blood vessels and cerebrospinal fluid (CSF). Because magnetic resonance (MR) images are constructed from analysis of the spin of various molecules, the diffusion coefficient can be used as a parameter that reflects the temperature of water molecules. We used diffusion-weighted imaging (DWI)-based MR imaging to measure the temperature of the CSF around the lateral ventricles in patients with idiopathic normal pressure hydrocephalus (iNPH).
Our study included 33 cases of iNPH (Group N, mean age, 75.1 years) and 40 age-matched controls (Group C, mean age, 74.5 years). We calculated CSF temperature in the ventricular domain using the conversion formula to evaluate the feasibility of iNPH study.
The mean temperatures were significantly higher in Group N (37.6°C ± 0.4°C) than Group C (36.7°C ± 0.5°C; P < 0.01). The cut-off value of 37.2°C (more than the mean + 2 standard deviations [SD] of the values in Group C) showed sensitivity of 72.4% and specificity of 77.5% for distinguishing the 2 groups. We confirmed improved CSF temperature in the lateral ventricles in all patients examined both before and after shunting.
Elevated ventricular temperatures in patients with iNPH (Group N) may represent a disturbance in heat balance. Our results showed that thermometry using DWI-based MR imaging can help in the noninvasive and consistent evaluation of CSF temperature and may thus provide a useful supplementary brain biomarker for iNPH.
大脑因脑代谢和脑血流产生大量热量，所产生的热量主要通过颅内血管和脑脊液（CSF）循环排出。由于磁共振（MR）图像是通过分析各种分子的自旋构建而成，扩散系数可作为反映水分子温度的参数。我们采用基于扩散加权成像（DWI）的磁共振成像来测量特发性正常压力脑积水（iNPH）患者侧脑室周围脑脊液的温度。
我们的研究纳入了33例iNPH患者（N组，平均年龄75.1岁）和40例年龄匹配的对照组（C组，平均年龄74.5岁）。我们使用转换公式计算脑室区域的脑脊液温度，以评估iNPH研究的可行性。
N组的平均温度（37.6°C±0.4°C）显著高于C组（36.7°C±0.5°C；P<0.01）。37.2°C（超过C组平均值+2个标准差[SD]）的临界值在区分两组时的灵敏度为72.4%，特异性为77.5%。我们证实，在所有接受分流术前和术后检查的患者中，侧脑室的脑脊液温度均有所改善。
iNPH患者（N组）脑室温度升高可能代表热平衡紊乱。我们的结果表明，基于DWI的磁共振成像测温有助于无创且一致地评估脑脊液温度，因此可能为iNPH提供一种有用的补充性脑生物标志物。
