问题 多项选择题

MRI应用于心脏大血管成像的优势有哪些().

A.无需任何对比剂即可成像

B.属无创性检查,无放射线辐射损伤,安全性高

C.MRA对冠脉的显示优于CTA和DSA

D.MRI为三维成像,可进行任意平面断层扫描

E.心脏电影可动态显示心脏内结构运动,并可对心功能进行更加全面而准确的评估

答案

参考答案:A, B, D, E

解析:MRI应用于心血管检查的优势在于:①无需任何对比剂即可成像,是由于心肌和血管壁组织与血流的信号存在良好的对比;②属无创性检查,也无放射线辐射损伤,有较高的安全性;③MRI为三维成像,可进行任意平面断层扫描;④MRI心脏电影可动态显示心脏瓣膜运动、血流动力学和心肌收缩率等,并可对心功能进行更加全面而准确的评估。在冠脉显示的图像质量上CTA和DSA优于MRA检查。

阅读理解

     I credit my typing skill to so many hours of chatting online. Unfortunately, as my typing speed

increased on the Internet, all grammatical rules went out of the window. You see instant messages

have their own shorthand language and grammar isn't important, of which even a newbie (新手) is

aware. They can leave out articles, subjects (主语), pronouns, etc. They can misspell or "respell"

almost any word. They often ask "A/S/L" when they first chat. Abbreviations (缩写) and

capitalizations (大写) are particularly important. English-speaking instant messengers also refuse

to burden themselves with punctuation and capitalization.

    After I came back China, I discovered not one but two instant messaging crazes. The first, which

brought back memories of my previous addiction to the computer, was QQ. I can see evidence that

the Chinese have the same kind of separate instant messaging language, even when they chat in

English. My first word in this language, for example, was "ft". This abbreviation for "faint" is used

whenever there is a need to express surprise. I also discovered that Chinese use the same kind of

abbreviation for a laugh. And there is an extraordinary number of smileys (表情符) to the "vomit"

and "army soldier" smileys. There is even a SARA smiley.

     After QQ, there is another, perhaps more widespread messaging trend. You guessed it-cell phone

text messaging. I now understand how useful text messaging is and why it is so common. I admit that

I have been guilty of sending text messages while walking outside or sitting on the subway. Who

hasn't ? No matter where I go, I see people on their cell phones, messaging. In fact, it's rare to see

someone actually talking on their phone!

     So it looks as if there is no escape from the instant messaging crazes, no matter where in the

world I go. And that's plainly not going to change. In the end, though, I can't complain: instant

messaging is quick, it's cheap, it's easy and it's extremely fun too. And after all, everyone's doing it.

1. The underlined phrase "went out of the window" in Paragraph 1 probably means       

A. increased  

B. occurred  

C. disappeared  

D. changed

2. Which of the following is true according to the passage?

A. Grammar and correct spelling are very important while chatting online. 

B. There are enough smileys and icons to express yourselves while chatting on line.

C. The writer is skilled at typing and once was addicted to online games.

D. It is impolite to leave out some unimportant words or letters while chatting online.

3. The writer believes that instant messaging is          .

A. full of fun but time-consuming  

B. widespread but unnecessary

C. quick but difficult to do  

D. common, used and cheap

4. Which might be the main idea of the passage?

A. Who can escape QQ and cell phone text messaging?  

B. Why is instant messaging so popular?

C. Chatting online is good for your typing skill.

D. Chatting on QQ is natural for people.    

判断题