一、前言虽然标准X射线血管成象法在一次显示中可以复盖大面积的血管,并给出高分辨率的图象,但它仍具有一些缺点,因而促使人们研究其它的成象方法。其主要缺点大概是不舒服和注射放射性不透明染料的危险,它经常需要进行常规麻醉。加之想使患者尽量少接受电离辐射,有时导致勉强进行血管造影,虽然这种研究的结果对临床是有用的。因为需要寻找一种无损的血管成象方法,以致许多人员进行着这项研究,以期在 I. INTRODUCTION Although standard X-ray angiography can cover large areas of blood vessels in a single display and give high-resolution images, it still has some drawbacks, prompting one to study other imaging modalities. The main drawback is probably the uncomfortableness and danger of injecting radioactive opaque dyes, which often require routine anesthesia. Coupled with the desire to make patients receive as little ionizing radiation as possible, it sometimes leads to barely angiographic findings, although the results of such studies are clinically useful. Because of the need to find a nondestructive method of angiography, many people conducted the study with a view to