Feasibility of Neuronavigation System Guiding Transcranial Focused Ultrasound Induced Blood-Brain Barrier Disruption in Large Animal

• Main Authors: Jia Sing Wu, 吳家興
• Other Authors: H. L. Liu
• Format: Others
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/67211968565729130845

碩士 === 長庚大學 === 電機工程學系 === 99 === Focused ultrasound has been shown to be able to locally and reversibly increase the permeability of the blood–brain barrier (BBB). However, the accurate focal-beam targeting is essential when steering the focal energy into the deep brain. Nowadays, the current solution is to utilize MRI to provide anatomical information for pre-procedure targeting, MR-thermometry during the treatment, and post-procedure monitoring and evaluation (also known as magnetic-resonance guided focused ultrasound, or MRgFUS), and the technique is mature and has been widely used for brain tumor thermal ablation. However, since MR thermometry cannot be applied for BBB-opening process, the other tools such as neuronavigation may also play a substitute of the MR to guide the procedure. Our system combines a 400-kHz focused ultrasound transducer with a neurosurgical navigation system to adjust the accuracy between target location and focal point of the transducer. The BBB was disrupted transcranially in a 4-week newborn swine brains by delivering burst-tone ultrasonic energy under the presence of microbubbles. The pre- and post-experimental process was monitored in vivo by MRI. Evans Blue dye was serves as an indicator to verify the BBB disruption in gross animal sectioning, HE and TUNEL staining was conducted for brain tissue damage and cell apoptosis analysis. This study shows that neuronavigation can successfully guide the focal beam with comparable precision to neurosurgical stereotactic procedures (discrepancy about 2.3±0.9 mm). Acoustic pressure that can successfully open BBB was increased to 0.43 MPa due to the increased thickness of the large animals (3-5 mm). This study provides evidence that the transcranial focused ultrasound can successfully induce BBB opening in a large animal, and also verifies the feasibility of using neuronavigation to guide the procedure.