University of Alberta, Department of Electrical and Computer Engineering, Edmonton, Alberta T6G 2V4, Canada.
J Biomed Opt. 2010 Sep-Oct;15(5):056008. doi: 10.1117/1.3491126.
Both photoacoustic imaging and power Doppler ultrasound are capable of producing images of the vasculature of living subjects, however, the contrast mechanisms of the two modalities are very different. We present a quantitative and objective comparison of the two methods using phantom data, highlighting relative merits and shortcomings. An imaging system for combined photoacoustic and high-frequency power Doppler ultrasound microscopy is presented. This system uses a swept-scan 25-MHz ultrasound transducer with confocal dark-field laser illumination optics. A pulse-sequencer enables ultrasonic and laser pulses to be interlaced so that photoacoustic and power Doppler ultrasound images can be coregistered. Experiments are performed on flow phantoms with various combinations of vessel size, flow velocity, and optical wavelength. For the task of blood volume detection, power Doppler is seen to be advantageous for large vessels and high flow speeds. For small vessels with low flow speeds, photoacoustic imaging is seen to be more effective than power Doppler at the detection of blood as quantified by receiver operating characteristic analysis. A combination of the two modes could provide improved estimates of fractional blood volume in comparison with either mode used alone.
光声成像和功率多普勒超声都能够对活体的脉管系统进行成像，然而，这两种模式的对比机制却有很大的不同。我们使用体模数据对这两种方法进行了定量和客观的比较，突出了它们各自的优缺点。本文提出了一种结合光声和高频功率多普勒超声显微镜的成像系统。该系统使用了一个 25MHz 的扫频超声换能器，以及共焦暗场激光照明光学元件。脉冲序列器使超声和激光脉冲能够交织，从而可以对光声和功率多普勒超声图像进行配准。在具有不同血管大小、流速和光学波长组合的流动体模上进行了实验。对于血流体积检测任务，功率多普勒在大血管和高速流中具有优势。对于低速流动的小血管，光声成像在检测血液方面比功率多普勒更有效，这可以通过接收器工作特性分析来量化。与单独使用任何一种模式相比，两种模式的结合可以提供对分流血流量的更好估计。
