Noninvasive MR imaging-guided focal opening of the blood-brain barrier in rabbits
Noninvasive MR imaging-guided focal opening of the blood-brain barrier in rabbits
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DOI：
10.1148/radiol.2202001804
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发表时间：
2001-09-01
期刊：
影响因子：
19.7
通讯作者：
Jolesz, FA
中科院分区：
文献类型：
--
作者：
Hynynen, K;McDannold, N;Jolesz, FA
目的：确定聚焦超声束能否在不损伤周围脑组织的情况下局部打开血脑屏障，以及是否可以使用磁共振成像来监测这一过程。材料和方法：对18只兔的大脑进行4~6个位置的超声(脉冲超声)，时间峰值声功率为0.2~11.5W。每次超声前，将超声造影剂注入兔耳静脉。在超声检查过程中，获得了一系列快速或受损的梯度回波磁共振图像，以监测温度升高和潜在的组织变化。声学检查后数分钟、1~48小时后复查的对比剂增强磁共振图像用于显示血脑屏障开放情况。结果：磁共振成像对比剂的检测证实了血脑屏障的开放。使用的最低功率水平产生了血脑屏障的开放，而不会损害周围的神经元。对比度增强与快速破坏梯度回波MR图像中焦点信号强度的变化相关。结论：在超声造影剂存在的情况下，聚焦超声照射可持续打开血脑屏障。磁共振成像信号强度的变化可能有助于检测超声治疗过程中血脑屏障的开放程度。
PURPOSE: To determine if focused ultrasound beams can be used to locally open the blood-brain barrier without damage to surrounding brain tissue and if magnetic resonance (MR) imaging can be used to monitor this procedure.MATERIALS AND METHODS: The brains of 18 rabbits were sonicated (pulsed sonication) in four to six locations, with temporal peak acoustic power ranging from 0.2 to 11.5 W. Prior to each sonication, a bolus of ultrasonographic (US) contrast agent was injected into the ear vein of the rabbit. A series of fast or spoiled gradient-echo MR images were obtained during the sonications to monitor the temperature elevation and potential tissue changes. Contrast material-enhanced MR images obtained minutes after sonications and repeated 1-48 hours later were used to depict blood-brain barrier opening. Whole brain histologic evaluation was performed.RESULTS: Opening of the blood-brain barrier was confirmed with detection of MR imaging contrast agent at the targeted locations. The lowest power levels used produced blood-brain barrier opening without damage to the surrounding neurons. Contrast enhancement correlated with the focal signal intensity changes in the magnitude fast spoiled gradient-echo MR images.CONCLUSION: The blood-brain barrier can be consistently opened with focused ultrasound exposures in the presence of a US contrast agent. MR imaging signal intensity changes may be useful in the detection of blood-brain barrier opening during sonication.