问题 问答题 简答题

夹层动脉瘤的MRI表现有哪些?

答案

参考答案:

由于主动脉腔呈流空信号,MRI可清晰显示主动脉内撕裂的内膜瓣片,后者呈中等信号,在横断面将动脉腔分为两半,在矢状面或冠状面呈自上而下的线状间隔,将主动脉分为真、假两腔,真腔内为流空黑影,假腔内血流信号较高或因血栓形成而呈高信号。部分病例可见主动脉影增宽、主动脉壁渗漏征象,后者表现为主动脉管壁明显增宽、纵隔或胸腔积液等。夹层动脉瘤MRI表现典型,但一定要在同一解剖位置、两个不同方位的影像上均见到撕裂内膜片方可诊断。 

阅读理解

阅读理解。

     Welcome to Phillip Island Nature Park and the penguin Parade (企鹅列队). You will see the world's

smallest penguins- the little penguins appearing from the ocean and crossing the beach to their home in line.

It's a natural experience. Remember the Little penguins are wild. You are a visitor to their home.

     Making the most of your visit Here are some helpful hints (提示):

●The Penguins Parade last 50 minutes from the time penguins first cross the beach.

●Dress in warm clothes, for the Parade is in the open air on the beach.

●It is best to get down to the beach at least 15 minutest before the parade begins.

Protecting the Penguins

      We do have some simple rules-designed to protect the penguins and make your visit more enjoyable.

●Photography-including video cameral is not allowed. Photography during the Parades. Make sure that your

cameral is placed inside your bag, or in a bag provided, before walking down to the beach, Photographs can

be bought at proper price in the gift shop.

●Smoking is not allowed anywhere.

●And remember, the penguins are wild birds so please don't try to touch them.

1. During the Penguin Parade, people ________.

A. are allowed to smoke

B had better wear warm clothes.

C. have to hand in their bags

D. Can take photos of the penguins

2. Which of the following statements is WRONG?

A. The Little Penguins go back home in line.

B. The whole Penguin Parade lasts 50 minutes.

C. People have a chance to touch the penguins.

D. The Penguin Parade takes place on the beach.

3. The passage is written mainly to ________.

A. help make people's visit more pleasant

B. introduce the life of the Little Penguins

C. welcome people to Phillip bland Nature Park

D. encourage people to protect the Little Penguins

不定项选择