卵巢肿瘤中最常见的是 ()
A. 浆液性囊腺瘤
B. 黏液性囊腺瘤
C. 内胚窦瘤
D. 无性细胞瘤
E. 颗粒细胞瘤
When the writer first came to the capital____.
A. he had been very reluctant to leave his mother
B. his mother had not wanted him to leave home
C. he had made no preparations for his journey south
D. he had sent his possessions on ahead in a trunk
李某，52岁。1周来进行性双下肢瘫痪，大便障碍，体温正常。胸4水平以下深、浅感觉丧失和截瘫。脑脊液检查压力正常，白细胞90×106／L(80个／mm3。)，淋巴细胞占80％，蛋白轻度增高。最可能的诊断为 ()
A. 脊髓出血
B. 急性脊髓炎
C. 脊髓肿瘤
D. 多发性硬化
E. 急性硬膜外脓肿
下列对2D-TOF与3D-TOFMRA的比较，叙述错误的是
A. 2D-TOF流入饱和效应小，对慢流、血流方向一致的血管显示好;流动-静止对比好
B. 3D-TOF流人饱和效应明显，成像块厚受血管流速制约;信噪比好
C. 2D-TOF层面厚，空间分辨力差;相位弥散强，弯曲血管信号有丢失
D. 3D-TOF层厚较薄，空间分辨力高;对复杂弯曲血管的信号丢失少
E. 相同容积2D-TOF较3D-TOF成像时间长
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