Dynamic and Precise Visualization of Contrast Agent in Blood Vessels with Motion Correction

摘要

We have developed a new ultrasound imaging method for the visualization of vascularity with less than 500 μm in width applicable to tissues naturally moving caused by respiration or heart beats. In our method, we utilize the least square method based on tissue-motion measurement method previously reported, which divides an image into extremely small regions so that the loss of correlation caused by tissue motion can be virtually ignored. We averaged images of tissues with contrast agents after correcting for the tissue motion on the basis of measurement results. In vivo results of experiments using rabbit kidneys revealed that the vascularity including peripheral vessels, e.g., those in the renal cortex, could be clearly imaged without any motion artifact by averaging more than 30 frames. Moreover, it was indicated that a pseudo-three-dimensional imaging of small vessels can be achieved by this method utilizing slight tissue motions in the slice direction during obtaining frames to be averaged. In another experiment using tumor-implanted rabbits, it was also found that neovascularity in a tumor tissue could be identified more clearly on a time-averaged image than on a conventional image.