问题 单项选择题

关于单层螺旋CT扫描的叙述,错误的是()

A.可减少对比剂用量

B.可产生阶梯状伪影

C.可以进行CT血管成像

D.采集到的是一个非平面数据

E.容积扫描优于非螺旋CT

答案

参考答案:C

解析:单层螺旋CT扫描主要有以下优点:①整个器官或一个部位可在一次屏住呼吸下完成。②由于没有层与层之间的停顿,一次扫描检查时间缩短。③屏息情况下容积扫描,不会产生病灶的遗漏。④患者运动伪影因扫描速度快而减少。⑤可任意地、回顾性重建,无层间隔大小的约束和重建次数的限制。⑥单位时间内扫描速度提高,使对比剂的利用率提高。⑦容积扫描,提高了多平面和三维成像图像的质量。

阅读理解

阅读理解。

     When I was 13, my bedroom walls were covered with posters of the Monkees and Beatles. I wrote fan

letters and daydreamed about meeting the objects of my affections. I begged my parents to attend every rock

concert and watch every TV show featuring my favorite celebrities (名人) ; my friends and I discussed for

hours all the things we would say and do when we met our favorite movie stars and pop singers. I drove my

mother crazy! But after a few years, my obsession (迷恋) stars faded as I matured and gained the confidence

to socialize with "real" boys.

     In the 35 years since I was a teenager, celebrity worship (崇拜) has increased among teens due to the

explosion of television celebrity gossip shows, and instant access to celebrity news on the Internet. It's no

wonder that many teens are obsessed with stars when news programs often are filled with entertainment

stories and the lives of celebrities.

     Celebrity worship syndrome (综合征) is now considered a personality disorder. While it is normal for

teenagers to follow the lives of their favorite stars, parents should try to monitor everything their child finds

interesting. Parents should take action if they suspect a teen is too obsessed with celebrities and showing little

interest in school or withdrawing from the family.

     When teens talk a lot about celebrities and view them as just means of entertainment, this is considered

normal celebrity worship. However, when a teenager is obsessed with a star and often expresses a desire to

have a close personal relationship with a celebrity or feels they have a special connection to a star, this may

be the time for concern. Recent studies have shown that teens who develop an unhealthy obsession with

celebrities often suffer from low self confidence and depression. Teens who are overly obsessed with stars

often have damaged relationships with their parents.

1. The first paragraph is intended to tell us ____.

A. it's normal for a teen to have celebrity worship

B. celebrity worship can cause serious problems

C. parents needn't worry about celebrity worship

D. celebrity worship only exists among teens

2. We learn from the second paragraph that ____.

A. teens today are not so obsessed with celebrities

B. the author is surprised at celebrity worship

C. the media greatly contributes to celebrity worship today

D. celebrities expose their lives too much

3. Parents should become concerned when their children ____.

A. talk a lot about celebrities with others

B. put up celebrity posters in their bedrooms

C. ask to go to their favorite star's concert

D. desire a close personal relationship with their favorite star

4. The last paragraph implies that ____.

A. parents should not care too much about a child's celebrity worship

B. celebrity worship syndrome can be a serious problem if left overlooked

C. children can normally get out of celebrity worship when they are older

D. children with celebrity worship usually have high opinion of themselves

5. What is most likely to be talked about in the paragraph following the passage?

A. The harm of celebrity worship syndrome.

B. More signs of celebrity worship syndrome.

C. What to do with children's celebrity worship syndrome.

D. Who will suffer most from celebrity worship syndrome.

问答题 简答题