Photoacoustic contrast agent based active ultrasound imaging

摘要

Electromagnetic energy is applied to thereby oscillate a bubble that is then insonified to produce an echo (260) for reception and analysis to afford imaging of the region of the bubble. To create the bubble, the energy may be applied to a nano particle (232) of a contrast agent whose consequent internal nano- or micro-bubbles offer, with novel pulsing techniques, greater sensitivity, and which can permeate outside vasculature (216) prior to being energized thereby affording quantification of vascular permeability and delivery of targeting molecules. The particle can include an absorbing and an evaporating parts, the irradiation (204), as by near-infrared laser, causing the phase change that gives rise to the bubble. The echo may occur in response to ultrasound interrogation (220) of the activated contrast agent, which could entail pulse inversion, power modulation or contrast pulse sequence imaging, with persistence processing. The contrast agent might be mixed with microbubble based ultrasound contrast agent to facilitate the timing of bubble activation.

主权项

1. A contrast agent based active ultrasound imaging method, comprising:
injecting a contrast agent mixture (i) a nanoparticle-based contrast medium that comprises nanoparticles and (ii) an additional contrast agent into a subject with respect to a vasculature of a target region; detecting an inflow of the additional contrast agent of the contrast a ent mixture in the vasculature of said target region; applying pulsed electromagnetic energy to the nanoparticle-based contrast medium located in said target region (i) to cause a phase change in an evaporation part of the nanoparticles that produces bubbles and (ii) to further produce oscillating bubbles (ii)(a) from the bubbles produced by the phase change in the evaporation part of the nanoparticles (ii)(b) in response to an ongoing on and off energy absorption of an absorbing part of the nanoparticles in response to applying the pulsed electromagnetic energy, wherein the oscillating bubbles resonate at a frequency that is detectable by an interrogating ultrasound of an active ultrasound imaging of the vasculature of said target region; and insonifying the oscillating bubbles to produce echoes for reception and analysis by the active ultrasound imaging of the vasculature of said target region, wherein the active ultrasound imaging comprises low mechanical index imaging at low power so that a destruction of the oscillating bubbles is avoided, and wherein (i) said applying of pulsed electromagnetic energy is commenced, and (ii) said low mechanical index imaging is performed, (iii) at a concurrent time in response to (iii)(a) an inflow of the nanoparticle-based contrast medium injected into the subject with respect to the vasculature of said target region being detected via detecting the inflow of the additional contrast agent of the contrast agent mixture in the vasculature of said target region and (iii)(b) for which a portion of the inflow of the nanoparticle-based contrast medium detected in the vasculature of said target region has permeated outside the vasculature of said target region.