Department of Neurological Surgery, Weill Cornell Medical College, New York, New York, USA.
Department of Radiology, Weill Cornell Medical College, New York, New York, USA.
World Neurosurg. 2021 Jan;145:567-573. doi: 10.1016/j.wneu.2020.08.051.
The ability of ultrasonography to safely penetrate deeply into the brain has made it an attractive technology for neurological applications for almost 1 century. Having recognized that converging ultrasound waves could deliver high levels of energy to a target and spare the overlying and surrounding brain, early applications used craniotomies to allow transducers to contact the brain or dural surface. The development of transducer arrays that could permit the transit of sufficient numbers of ultrasound waves to deliver high energies to a target, even with the loss of energy from the skull, has now resulted in clinical systems that can permit noninvasive focused ultrasound procedures that leave the skull intact. Another major milestone in the field was the marriage of focused ultrasonography with magnetic resonance thermometry. This provides real-time feedback regarding the level and location of brain tissue heating, allowing for precise elevation of temperatures within a desired target to lead to focal therapeutic lesions. The major clinical use of this technology, at present, has been limited to treatment of refractory essential tremor and parkinsonian tremor, although the first study of this approach had targeted sensory thalamus for refractory pain, and new targets and disease indications are under study. Finally, focused ultrasonography can also be used at a lower frequency and energy level when combined with intravenous microbubbles to create cavitations, which will open the blood-brain barrier rather than ablate tissue. In the present review, we have discussed the historical and scientific foundations and current clinical applications of magnetic resonance-guided focused ultrasonography and the genesis and background that led to the use of this technique for focal blood-brain barrier disruption.
超声能够安全地深入穿透大脑，这使得它成为近一个世纪以来神经科学应用中极具吸引力的技术。人们已经认识到汇聚的超声波能够向目标传递高强度的能量，同时避免对大脑的上层和周围组织造成损伤。早期的应用采用开颅术来允许换能器接触大脑或硬脑膜表面。现在，已经开发出了能够允许足够数量的超声波穿透并向目标传递高强度能量的换能器阵列，即使能量从颅骨中损失，也可以实现非侵入性的聚焦超声程序，而颅骨保持完整。该领域的另一个重要里程碑是将聚焦超声与磁共振测温技术相结合。这提供了关于脑组织加热水平和位置的实时反馈，允许在期望的目标内精确升高温度，从而导致焦点治疗性损伤。目前，这项技术的主要临床应用仅限于治疗难治性原发性震颤和帕金森震颤，尽管这种方法的第一项研究针对的是难治性疼痛的感觉丘脑，并且正在研究新的靶点和疾病适应症。最后，当与静脉内微泡结合使用时，聚焦超声也可以在较低的频率和能量水平下使用，以产生空化作用，从而打开血脑屏障而不是消融组织。在本综述中，我们讨论了磁共振引导聚焦超声的历史和科学基础以及当前的临床应用，以及导致该技术用于焦点血脑屏障破坏的起源和背景。
