Real-time implementation of a dual-mode ultrasound array system: In vivo results

Background, Motivation and Objective: We have previously presented a method of ultrasound image guidance known as a dual-mode ultrasound array (DMUA). A DMUA uses the same elements for imaging and therapy creating an inherent registration between the two modalities and allowing for precise HIFU targeting. Previous results have demonstrated the abilities of DMUAs on phantoms and in vitro tissues with offline data processing, here we present in vivo results from a fully functional, real-time implementation of a DMUA. Statement of Contribution/Methods: This system utilizes high-performance FPGAs and GPUs to implement a novel ultrasound-guided focused ultrasound (USgFUS) platform. This platform uses 33 frames per second synthetic aperture (SA) imaging to provide guidance for the selection of therapeutic targets. Single transmit focus (STF) imaging is interleaved with therapy at 1000 frame per second to provide real-time feedback on the treatment progress. The array contains a central opening to allow the coaxial alignment of a diagnostic transducer for image fusion between the diagnostic and DMUA imaging modalities. Results: A 3.5 MHz, 32 element DMUA was used for HIFU treatments in swine and rat animal models. The SA imaging allowed for the recognition of tissue structure and the tracking of natural tissue motion. STF imaging during therapy allowed for the detection of HIFU induced echogenic changes. The DMUA images allowed for the targeted placement of HIFU shots with sub-millimeter and millisecond spatial and temporal resolutions, respectively. Histological examinations have confirmed thermal lesion formation within the wall of the vessel. Discussion and Conclusions: Advances in computing power and array technology have enabled the development of a DMUA as a real-time USgFUS platform. These results represent the first in vivo demonstration of a DMUAs imaging and therapeutic capability. The system demonstrates the ability to image anatomical structures and deliver HIFU therapy safely and efficaciously.