MRI monitoring of heating produced by ultrasound absorption in the skull: In vivo study in pigs
MRI monitoring of heating produced by ultrasound absorption in the skull: In vivo study in pigs
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DOI：
10.1002/mrm.20043
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发表时间：
2004-05-01
影响因子：
3.3
通讯作者：
Hynynen, K
中科院分区：
文献类型：
--
作者：
McDannold, N;King, RL;Hynynen, K
本研究的目的是测试 MR 测温法在监测超声波照射期间颅骨加热引起的大脑表面和头皮温度升高方面的实用性。对三头猪的 11 个部位进行非聚焦超声照射（频率 = 690 kHz；声功率 = 8.2-16.5 W；持续时间 = 20 秒）。 MR 测温（一种化学位移技术）显示，在 10 W 的声功率水平下，大脑表面和头皮的体内平均温升分别为 2.8°C +/- 0.6°C 和 4.4°C +/- 1.4°C。头皮上的温升与插入头骨附近的热电偶探头测量的结果一致（平均温升 = 4.6 摄氏度 +/- 1.0 摄氏度）。换能器的特性表明，声功率为 10 W 时，平均声强度为 1.3 W/cm(2)。如此处所示，利用基于 MRI 的测温法监测头骨附近温升的能力将允许在经颅聚焦超声临床试验期间进行安全监测。 (C) 2004 Wiley-Liss, Inc.
The purpose of this study was to test the utility of MR thermometry for monitoring the temperature rise on the brain surface and in the scalp induced by skull heating during ultrasound exposures. Eleven locations in three pigs were targeted with unfocused ultrasound exposures (frequency = 690 kHz; acoustic power = 8.2-16.5 W; duration = 20 s). MR thermometry (a chemical shift technique) showed an average temperature rise in vivo of 2.8degreesC +/- 0.6degreesC and 4.4degreesC +/- 1.4degreesC on the brain surface and scalp, respectively, at an acoustic power level of 10 W. The temperature rise on the scalp agreed with that measured with a thermocouple probe inserted adjacent to the skull (average temperature rise = 4.6degreesC +/- 1.0degreesC). Characterization of the transducer showed that the average acoustic intensity was 1.3 W/cm(2) at an acoustic power of 10 W. The ability to monitor the temperature rise next to the skull with MRI-based thermometry, as shown here, will allow for safety monitoring during clinical trials of transcranial focused ultrasound. (C) 2004 Wiley-Liss, Inc.