用SE脉冲序列测量T1值的描述，正确的是（）
A.固定TE，变化TR的多个SE序列
B.选用短TR、短TE的图像，可测量T1值
C.在T1加权图像中，图像的亮度代表T1值
D.利用常规SE脉冲序列可以测量T1值
E.SE序列是测量T1值的最佳脉冲序列
参考答案：A
解析：
TE实际上是90°射频脉冲激发后到自旋回波产生的等待时间。但不是T1权重越重越好，临床中根据需要选择，一般如果要最大限度地区分两种组织的T1弛豫差别，SE序列的TR选择在两种组织T1值的平均值附近最好，T1对比最好。T1WI上T1值越短，其信号强度越高。
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| In most schools and universities teachers give their l marks (分数) for their work. All students hate a " 2 " and are happy if their teacher gives them an "A". Now, at one American university the students and the teachers must work hard 3 they want good marks. During classes the students give their teachers 4 Each desk has a "boredom button(厌倦按钮) " on it. If a student thinks that the lecture is 5 he can press the special button. When he does this, he turns on a 6 _ at the back of the classroom.' There's one light there for every student. The teacher can 7 _ the lights and he can see if his students think the class is interesting or boring. The teacher cannot 8 which student is pressing the button. So the students can be completely " 9 ". If too many lights come on at the back of his class, a teacher knows that he must do something quickly and make the _ 10 more interesting. What do you think the teachers think about the "boredom button"? Do you think it's a good idea for schools? | |||
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