排序方式: 共有21条查询结果,搜索用时 15 毫秒
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大脑皮层运动功能区的脑功能成像 总被引:3,自引:0,他引:3
MR扫描中通过某些特定的功能活动刺激 ,能够对大脑功能区进行成像 ,即脑功能成像 (functionalMR ,fMR) [1] 。为此 ,我们应用fMR成像观察了大脑皮层运动中枢的功能成像。一、对象与方法1.对象 :选择 15名正常志愿者接受脑运动功能区的fMR成像 ,年龄 2 5~ 41岁 ,男 10名 ,女 5名。fMR扫描前 ,要求志愿者练习拇指与其余 4指的对指运动 ,并在扫描中静止不动 ,按指令进行对指运动。2 .扫描条件 :使用东芝Visart1.5T超导MR成像系统 ,标准头正交线圈 ,平面回波脉冲序列 ,血氧水平依赖法 (blood oxyg… 相似文献
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颅内巨大动脉瘤的MR影像学分析 总被引:4,自引:0,他引:4
目的 分析颅内巨大动脉瘤的MR影像学表现。方法 搜集 40例经手术病理证实的颅内巨大动脉瘤。结果 颅内巨大动脉瘤的MR信号表现多样 ,主要与动脉瘤内是否出现血栓 ,血栓的大小和形成时间的长短 ,和动脉瘤引起的继发改变等因素有关。瘤腔信号 :绝大部分巨大动脉瘤表现出典型的流空现象或流动信号。瘤腔水平可见的血管流动伪影 ,注药后明显强化。血栓信号 :大部分动脉瘤中出现了血栓 ,血栓信号差异很大 ,多呈层状或涡状的混杂信号 ,增强扫描无强化。无血管流空伪影。DSA和MRA可显示动脉瘤瘤腔 ,不能显示动脉瘤内是否存在血栓或闭塞 ,低估动脉瘤的大小。绝大部分动脉瘤可在MRA中证实。结论 MR可清楚显示颅内巨大动脉瘤的全貌 ,包括瘤腔和血栓形成情况 ,是DSA检查的必要补充。 相似文献
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蝶窦黏液囊肿的临床表现与影像学诊断 总被引:1,自引:0,他引:1
蝶窦黏液囊肿少见,仅占鼻窦黏液囊肿的1%[1].本文总结了自1999年1月~2007年5月本院收治的蝶窦黏液囊肿患者17例,报道如下. 相似文献
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脊髓表皮样囊肿的MR诊断 总被引:13,自引:0,他引:13
目的分析脊髓表皮样囊肿的MR表现,以提高对该病的神经放射学认识。材料与方法搜集18例经手术病理证实的脊髓表皮样囊肿。重点分析了肿瘤的好发年龄、部位、MR信号特点和肿瘤的增强情况。结果在本组病例中,病人年龄最小4岁,最大42岁,平均年龄24.5岁。本组病例全部发生于圆锥附近,边缘清楚。大部分肿瘤长度小于2个椎体长度(16/18),2例肿瘤长度大于3个锥体长度,T1加权像肿瘤呈均匀的等(6/18)、高(2/18)和混杂信号(10/18)。T2加权像呈高信号,边缘可呈等T2信号。在7例行增强扫描的病人中,有4例肿瘤周围可见轻微强化,3例无强化。9例肿瘤内可见脂肪信号。本组中未见其他有关先天性畸形。结论脊髓内表皮样囊肿的MR表现较具特征性。该病多见于青年患者,好发于圆锥附近,多呈长T1、T2信号。增强扫描无或仅有周围轻微强化。 相似文献
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Objective To observe the motor cortex activitie s on fMR imaging. Method The fMR study of motor cortex was performed in 15
normal volunteers using 1. 5T superconducting MR system, EPI pulse sequences, and BOLD fMR imaging. Six axial slices centered approxi-
matdy at the precentral gyrus was obtained wit h or without both hands finger tapping motion under the operator instruction during the scanning.
Pixels with significant signal differences ( P <0.0001) between with and without finger tapping were calculated as functional signal. The
functional signal was superimposed on the corresponding T1 WI and brain water images Results The motor cortex ac tivities stimulated by finger
tapping show as the area of increased signalintensity. The location of actwities is correspondent very well with the location of motor cortex. Most
of activities present at the lateral aspect of precentral gyrus. In our group, the motion activities of left hemisphere is larger than that of right side
in 10 volunteers, almost same sixe in 3 volunteers, smaller than that of right side in 1 volunteer. The fMR scan failed in 1 volunteer. Super-
imposing the functional signals on the brain uner image may help to display the location of the activities. Conlusion fMR can show the
location and size of motor cortex. It is simple, fast, noninvasive, and very convenient to implements with routine MR study. 相似文献
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受病变累及的运动中枢fMR表现 总被引:1,自引:1,他引:0
目的观察正常及受病变累及的运动中枢的脑功能核磁共振成像(fMR)表现.方法通过双手对指运动使运动中枢功能活跃,然后对14例正常志愿者和36例运动中枢受累的病人进行运动功能区血氧水平依赖法(BOLD)fMR成像.结果通过双手对指运动使运动中枢功能活跃,正常志愿者和病人脑内产生了相应的功能信号,表现为功能区信号增高.在正常志愿者中,双侧半球运动功能区的位置基本对称,但大部分志愿者左侧半球功能信号稍强于对侧半球.在累及运动中枢病变的病人中,病变侧功能信号全部位于病变外或病变边缘,病变内未见功能信号.病侧功能区主要表现为功能信号降低、移位.结论BOLD法fMR可以很好的显示正常和病变的运动中枢,是评价运动中枢的有效方法. 相似文献
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By certain functional stimulates, the brain cortex becomes active. The MR scan has been proven to image these cortex activities by comparing the images with and without functional stimulates. The signal differences between the image with and without functional stimulates is related with the hemodynamic and metabolic changes induced by functional activities. This signal difference is very small, but detectable by MR system, and is the functional MR signal. The MR scan displaying the functio… 相似文献