| Summary: | 碩士 === 國立成功大學 === 生物醫學工程學系 === 106 === Recently, zebrafish has been considered as an ideal vertebrate for studying developmental biology, genetics, cancer, and cardiology, particularly for modeling tumorigenesis, angiogenesis, and regeneration in vivo. However, once the zebrafish has fully matured, its body loses transparency, thus conventional optical imaging techniques are difficult for imaging the internal anatomy and vasculature.
Since the acoustic wave has a better penetration ability than optical methods, high frequency (〉30 MHz) ultrasound (HFUS) was an alternative imaging modality for adult zebrafish imaging, particularly for echocardiography. However, the conventional HFUS is still difficult to visualize the vessels of zebrafish. In the present study, high frequency micro-Doppler imaging (HFμDI) based on ultrafast ultrasound imaging was proposed for zebrafish dorsal vascular mapping in vivo. Blood flow signals were extracted by eigen-based clutter filter with different settings. Experiments were performed using 8-months old wild-type AB line adult zebrafish. Blood vessels including intersegmental vessels (Se), dorsal longitudinal anastomotic vessel (DLAV), and dorsal aorta (DA) were observed clearly in both 2D and 3D HFμDI. The maximum imging depth of HFμDI is 4 mm and a minimum vessel diameter of 36 μm can be detected without using microbubbles. The maximum flow velocity ranging around 3-4 mm/s was found on the dorsal vessels of adult zebrafish. In addition, a 14.4% vasoconstriction was detected by HFμDI due to temperature changes of zebrafish living environment. Compared to conventional ultrasound Doppler imaging, indeed, HFμDI exhibits a good ability for small vessel imaging.
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