问题
单项选择题
脉冲序列中,使血液呈高信号的是()
A.进入层面效应,偶回波技术
B.流入性增强,飞越时间效应
C.舒张期血流增强,层面与血管平等
D.层面与血管垂直,偶回波技术
E.舒张期增强,飞越时间效应
答案
参考答案:A
解析:表现为高信号的血流:①流入增强效应。②舒张期假门控现象。③偶回波效应。④梯度回波序列(梯度回波序列血流呈现高信号)。
脉冲序列中,使血液呈高信号的是()
A.进入层面效应,偶回波技术
B.流入性增强,飞越时间效应
C.舒张期血流增强,层面与血管平等
D.层面与血管垂直,偶回波技术
E.舒张期增强,飞越时间效应
参考答案:A
解析:表现为高信号的血流:①流入增强效应。②舒张期假门控现象。③偶回波效应。④梯度回波序列(梯度回波序列血流呈现高信号)。
完形填空。 | |||
Traffic rules help to keep order on the road. They also help to keep people 1 . The pedestrian (行人) has as many rules to 2 as the driver of a car. You should wall on the sidewalk (人行道) or at the side of the road. Always look 3 before you wall across the street. If you like riding a bike, don't ride in the middle of the road or run 4 red traffic lights. When you ride a bike with a friend, don't look around or tall. Ifyou drive a car, you should 5 at the traffic lights. You must always 6 a seat belt (安全带). Without belts 7 the driver and the passengers may be badly hurt in a sudden accident. You may not need to take a bus, but 8 if you have to travel in one. Get on or get off a bus only when it comes to a 9 . When it is full, don't try to get inside 10 you may fall off. Traffic rules are also called Road Safety rules. | |||
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