2001/09/01 by Kullervo Hynynen, Nathan McDannold, Natalia Vykhodtseva +1 · 13 citations
Engineering · Medicine · Neuroscience · #Cerebrospinal fluid and hydrocephalus #Ultrasound Imaging and Elastography #Ultrasound and Hyperthermia Applications
paper · doi:10.1148/radiol.2202001804
openalex publication_date 2001/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
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.