问题 多项选择题

下列脑内血肿的MRI表现,正确的为

A.呈圆形或不规则形,其影像特征及信号演变与自发性脑内血肿一致

B.超急性期血肿T1WI呈略低信号,T2WI和PDWI呈高信号

C.急性期血肿T1WI呈等信号,T2WI呈低信号

D.亚急性期血肿T1WI呈等信号,T2WI呈高信号

E.慢性期血肿T1WI和T2WI上核心层和核外层均为高信号

答案

参考答案:A,C

解析: 脑内血肿呈圆形或不规则形,其影像特征及信号演变与自发性脑内血肿一致。超急性期血肿T1WI呈等或稍低信号,T2WI和PDWI呈高信号;急性期血肿T1WI呈等信号,T2WI呈低信号;亚急性期血肿T1WI呈高信号,T2WI呈低信号;慢性期血肿呈长T1、长T2信号。

选择题
阅读理解

Trees are useful to man in three important ways: they give him wood and other useful things, they give him cool places, and they help to stop drought and flood.

Unluckily, in many parts of the world, man has not found that the third of these points is the most important. Man wants to make money from trees, so he has cut them down in large numbers, only to find that without them he has lost the best friends he had. And also, he is usually too careless to plant and look after new trees. So the forests slowly disappear.

This does not only mean that man will have fewer trees. The results are even worse: for where there are trees, their roots break up soil-make the rain in-and also bind the soil, thus stopping it from being washed away easily; but where there are no trees, the rain falls on hard ground and flows away, causing floods and carrying away the rich top-soil. When all the top-soil is gone, nothing is left but useless desert.

1.The most important points of trees to man is ________.

A. they help him to make money               B. they give him cool

C. they give him wood and other things       D. they help him to stop drought and floods

2.In many places forests slowly disappear because ________ .

A. many trees have been cut down by man

B. new trees are not well looked after

C. man has not paid enough attention to planting trees

D. all the above

3.Land becomes desert after all trees are cut down because ________ .

A. roots of trees break up the soil   

B. there are too many rainfalls

C. strong winds bring a lot of sand

D. there are no longer trees to keep the rain and protect the top-soil.

4.Which title best fits the passage?

A. Trees and Man                                      B. The Function of Tree Wood

C. How do People do with Trees?                  D. The Usage of Tree Roots