Realtime Two-Dimensional Temperature Imaging Using Ultrasound. IEEE transactions on bio-medical engineering [IEEE Trans Biomed Eng] Journal article

We have previously introduced methods for noninvasive estimation of temperature change using diagnostic ultrasound. The basic principle was validated both in vitro and in vivo by several groups worldwide. Some limitations remain, however, that have prevented these methods from being adopted in monitoring and guidance of minimally invasive thermal therapies, e.g. RF ablation and high intensity focused ultrasound (HIFU). In this letter, we present first results from a realtime system for 2D imaging of temperature change using pulse-echo ultrasound. The frontend of the system is a commercially available scanner equipped with a research interface, which allows the control of imaging sequence and access to the RF data in realtime. A high frame-rate 2D RF acquisition mode, M2D, is used to capture the transients of tissue motion/deformations in response to pulsed HIFU. The M2D RF data is streamlined to the backend of the system, where a 2D temperature imaging algorithm based on speckle tracking is implemented on a graphics processing unit (GPU). The realtime images of temperature change are computed on the same spatial and temporal grid of the M2D RF data, i.e. no decimation. Verification of the algorithm was performed by monitoring localized HIFU-induced heating of a tissue-mimicking elastography phantom. These results clearly demonstrate the repeatability and sensitivity of the algorithm. Furthermore, we present in vitro results demonstrating the possible use of this algorithm for imaging changes in tissue parameters due to HIFUinduced lesions. These results clearly demonstrate the value of the realtime data streaming and processing in monitoring and guidance of minimally-invasive thermotherapy.

IEEE transactions on bio-medical engineering [IEEE Trans Biomed Eng]