问题 问答题 简答题

简述脑转移瘤的影像学表现。

答案

参考答案:

(1)脑内多发或者单个结节:CT平扫呈等密度或低密度,MRI一般呈长T1、长T2信号,但黑色素瘤转移呈短T1、短T2信号,瘤内出血则CT呈高密度、MRI呈短T1长T2信号。

(2)增强:呈结节状或环形强化,且能比增强前发现更多小结节灶。

(3)瘤周水肿和占位效应:一般明显,也可缺乏。

单项选择题
单项选择题 案例分析题

From childhood to old age, we all use language as a means of broadening our knowledge of ourselves and the world about us. When humans first 1 , they were like newborn children, unable to use this 2 tool. Yet once language developed, the possibilities for human kind’s future 3 and cultural growth increased.

Many linguists believe that evolution is 4 for our ability to produce and use language. They 5 that our highly evolved brain provides us 6 an innate language ability not found in lower 7 . Proponents of this innateness theory say that our 8 for language is inborn, but that language itself develops gradually, 9 a function of the growth of the brain during childhood. Therefore there are critical 10 times for language development.

Current 11 of innateness theory are mixed, however, evidence supporting the existence of some innate abilities is undeniable. 12 , more and more schools are discovering that foreign languages are best taught in 13 grades. Young children often can learn several languages by being 14 to them, while adults have a much harder time learning another language once the 15 of their first language have become firmly fixed.

16 some aspects of language are undeniably innate, language does not develop automatically in a vacuum. Children who have been 17 from other human beings do not possess language. This demonstrates that 18 with other human beings is necessary for proper language development. Some linguists believe that this is even more basic to human language 19 than any innate capacities. These theorists view language as imitative, learned behavior. 20 , children learn language from their parents by imitating them. Parents gradually shape their child's language skills by positively reinforcing precise imitations and negatively reinforcing imprecise ones.

请在3处填上正确答案()

A.attainments

B.feasibility

C.entertainments

D.evolution