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高手翻译~能译多少译多少,好的追加100以上悬赏!
CT is much more sensitive to iodine than projection radiography. CT clearly visualizes iodine concentrations of lmg/ml in a volume of less than 0.1 ml (see figure 2b). Projection imaging requiresat least 20 mg i/mlif an objectof lcm thickness is visualized, Angiography may serve as an example to illustrate the difference between CT and projection radiography. In spite of high contrast medium doses and very fast injection, intravenous DSA does not reliably yield clinically useful image quality because its sensitivity to iodine is too low. The contrast medium concentration in blood achieved with identical doses is fully sufficient for CT. Conversely, CTA is limited by its spatial and temporal resolution.
A very important feature is speed. The first CT scanners in the seventies took several minutes to acquire the data for a single slice. Short-lasting contrast enhancement was missed.
Equally important is spatial resolution. If contrast enhancement is restricted to small lesions, it may be missed if low spatial resolution results in the display of average density values over larger volumes. High spatial resolution of moving structures can only be achieved if data acquisition is fast enough to avoid movement artefacts. Movement is critical in organs within or close to the thorax or the heart or in any other organ, tissue or structure in patients who are unable to follow the instructions of radiographers or physicians during image acquisition. The previous chapter points out the dramatic progress in spatial and temporal resolution of modern CT scanners.CT discovers the mutti-talent of non-ionic low osmolar contrast media Non-invasive angiography and the visualization of perfusion, permeability and interstitial space.
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CT检查更为敏感,碘比投影X线摄影.可视化的CT明确碘浓度的轻机枪/毫升的体积小于0.1毫升(见图2b干扰素) .投影显像requiresat至少20毫克的I / mlif一个objectof显示模块厚度,血管造影可以作为一个例子来说明之间的差异CT和X线投影.尽管高对比度中等剂量和速度非常快注射,静脉注射造影不可靠产量临床有用的图像质量,因为它的灵敏度碘太低.对比剂的血液中的浓度达到相同剂量是完全足够了CT检查.相反的,是有限的造影其空间和时间分辨率.
一个非常重要的特点是速度.首次CT扫描仪在七十年了几分钟获得的数据为单层.短期持久对比增强被错过.
同样重要的是,空间分辨率.如果对比增强仅限于小病灶,可能错过如果低空间分辨率的结果显示平均密度值较大的卷.高空间分辨率的移动结构才能实现,如果数据采集的速度足以避免运动文物.运动是至关重要的机构内或接近胸部或心脏或其他任何机关,组织或结构,患者谁无法按照指示的放射技师或医师在图像采集.上一章指出了巨大进步空间和时间分辨率的现代CT扫描仪.CT discovers the mutti-talent of non-ionic low osmolar contrast media Non-invasive angiography and the visualization of perfusion,permeability and interstitial space.