Ultrasound for Visualization and Modification of Brain Tissue

Abstract

Absfrocf-Techniques for the detailed, in vivo visualization and modification of internal brain structures via ultrasonic means have been developed and studied in both animals and man. The instrumentation used in these studies includes high-gain large-aperhue ceramic transducers positioned in space by a specially adapted Cincinnati turret drill. Precise transducer positioning, ampliiTer gain, relief presentation, and other techniques are under on-line computer control; the system provides for the use of either simple, compound, or omnidirectional scanning modes. When the brain is viewed through an acoustically transparent window, essentially all soft-tissue fluid-filled space interfaces can be visualized, and in some instances gray-white matter interfaces can be seen clearly. Brain lesions produced by high-intensity focused ultrasound are tissue specific and can be shaped in vivo to conform with the complex geometry of a given brain structure. These ultrasonic lesions, as well as those produced by mechanical or electrolytic methods, can be visualized ultrasonically immediately after their placement.