Ultrasound line-by-line scanning method of spatial–temporal active cavitation mapping for high-intensity focused ultrasound

• Published in: Ultrasonics Vol. 54; no. 1; pp. 147 - 155
• Main Authors: Ding, Ting, Zhang, Siyuan, Fu, Quanyou, Xu, Zhian, Wan, Mingxi
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2014
• Subjects: Algorithms; Cavitation field; Contrast Media - therapeutic use; High-intensity focused ultrasound; High-Intensity Focused Ultrasound Ablation - methods; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Reproducibility of Results; Sensitivity and Specificity; Spatial–temporal distribution; Surgery, Computer-Assisted - methods; Ultrasonography - methods; Cavitation field; Spatial–temporal distribution; High-intensity focused ultrasound
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2013.04.011

•An ultrasound line-by-line scanning method for cavitation mapping was proposed.•We verified the method in tap-water and a tap-water filled cavity in the phantom.•The images obtained had both high temporal resolution and spatial resolution.•The method may be a useful tool in spatial–temporal cavitation mapping for HIFU. This paper presented an ultrasound line-by-line scanning method of spatial–temporal active cavitation mapping applicable in a liquid or liquid filled tissue cavities exposed by high-intensity focused ultrasound (HIFU). Scattered signals from cavitation bubbles were obtained in a scan line immediately after one HIFU exposure, and then there was a waiting time of 2s long enough to make the liquid back to the original state. As this pattern extended, an image was built up by sequentially measuring a series of such lines. The acquisition of the beamformed radiofrequency (RF) signals for a scan line was synchronized with HIFU exposure. The duration of HIFU exposure, as well as the delay of the interrogating pulse relative to the moment while HIFU was turned off, could vary from microseconds to seconds. The feasibility of this method was demonstrated in tap-water and a tap-water filled cavity in the tissue-mimicking gelatin–agar phantom as capable of observing temporal evolutions of cavitation bubble cloud with temporal resolution of several microseconds, lateral and axial resolution of 0.50mm and 0.29mm respectively. The dissolution process of cavitation bubble cloud and spatial distribution affected by cavitation previously generated were also investigated. Although the application is limited by the requirement for a gassy fluid (e.g. tap water, etc.) that allows replenishment of nuclei between HIFU exposures, the technique may be a useful tool in spatial–temporal cavitation mapping for HIFU with high precision and resolution, providing a reference for clinical therapy.