同步辐射成像技术对肢体微血管相位衬度成像的实验研究

Experimental study of Synchrotron radiation imaging of extremity microvascular phase contrast imaging

目的应用同步辐射光源类同轴相位成像技术检测大鼠后肢肌肉的微血管。方法取SD大鼠8只分别用生理盐水和硫酸钡对后肢动脉进行灌注，对不同厚度的标本进行普通x线和同步辐射相位衬度成像。另取1只大鼠，在不灌注对比剂的情况下检测肝脏、肺叶和肢体的血管。结果未灌注对比剂的肝脏和灌注生理盐水或硫酸钡的后肢可见血管显影。和普通x线成像比较，灌注硫酸钡的后肢标本可显示更清晰的血管树，可显示的最小血管直径为9μm。结论同步辐射成像技术有助于检测肢体微血管或新生血管。

Objective To visualize deep-level microvascular structure in rat hind limb by microangiographic technique, and compare images with those by conventional method. Methods Eight Sprague Dawley rats were used for ex vivo study. Either normal saline or barium sulfate solution was infused through the iliac artery catheter into the left hind limb. The specimens of different thickness were then imaged by synchrotron radiation source, and images were compared with those by conventional method. In synchrotron radiation imaging, in-line phase-contrast imaging technique was used, and phase contrast images were compared at different energy levels of monochromatic synchrotron radiation and object-image distances. One rat was used for synchrotron radiation imaging of the liver, lung, and limb without using any contrast. Results Using synchrotron radiation, blood vessel could be detected in the liver without using any contrast, and the hind limb infused with normal saline or barium sulfate solution. In addition, vessels in the hind limb infused with barium sulfate solution could be clearly depicted with more detail by synchrotron radiation imaging compared with conventional method, with the minimum visualized blood vessel about 9μm in diameter. Conclusion Synchrotron radiation-based microangiography provided a practical and effective mean to observe the microvasculature of limbs, which might be useful in assessment of angiogenesis in lower limbs.