IEEE Trans Ultrason Ferroelectr Freq Control. 2020 Sep;67(9):1811-1819. doi: 10.1109/TUFFC.2020.2988159. Epub 2020 Apr 15.
We report the time kinetics of fluorescently labeled microbubbles (MBs) in capillary-level microvasculature as measured via confocal microscopy and compare these results to ultrasound localization microscopy (ULM). The observed 19.4 ± 4.2 MBs per confocal field-of-view ( [Formula: see text]) are in excellent agreement with the expected count of 19.1 MBs per frame. The estimated time to fully perfuse this capillary network was 193 s, which corroborates the values reported in the literature. We then modeled the capillary network as an empirically determined discrete-time Markov chain with adjustable MB transition probabilities though individual capillaries. The Monte Carlo random walk simulations found perfusion times ranging from 24.5 s for unbiased Markov chains up to 182 s for heterogeneous flow distributions. This pilot study confirms a probability-derived explanation for the long acquisition times required for super-resolution ULM.
我们通过共聚焦显微镜报告了荧光标记微泡（MB）在毛细血管水平微血管中的时间动力学，并将这些结果与超声定位显微镜（ULM）进行了比较。观察到的每个共聚焦视场中的 19.4 ± 4.2 个 MBs（[公式]）与每个帧中预期的 19.1 个 MBs 计数非常吻合。完全灌注这个毛细血管网络的估计时间为 193 秒，这与文献报道的值相符。然后，我们将毛细血管网络建模为一个经验确定的离散时间马尔可夫链，通过单个毛细血管具有可调节的 MB 转移概率。蒙特卡罗随机游走模拟发现，对于无偏马尔可夫链，灌注时间从 24.5 秒到不均匀的流动分布的 182 秒不等。这项初步研究证实了超分辨率 ULM 需要长采集时间的概率解释。
