中国组织工程研究与临床康复
中國組織工程研究與臨床康複
중국조직공정연구여림상강복
JOURNAL OF CLINICAL REHABILITATIVE TISSUE ENGINEERING RESEARCH
2010年
4期
649-652
,共4页
拉链伪影%自旋回波序列%180°脉冲%自由感应衰减信号
拉鏈偽影%自鏇迴波序列%180°脈遲%自由感應衰減信號
랍련위영%자선회파서렬%180°맥충%자유감응쇠감신호
背景:磁共振成像会产生各种类型的伪影,经常出现的有运动伪影、卷褶伪影、金属伪影、部分容积效应伪影、化学位移伪影、相位伪影和拉链伪影等,但由自旋回波序列成像过程中形成拉链伪影的控制和校正方法还未见报道.目的:通过分析自旋回波序列成像过程中拉链伪影的产生机制,探索出一种新的消除拉链伪影的脉冲序列.方法:编写标准SE序列得到标准图,编写伪影序列得到直线干扰图像和拉链伪影图,编写改进序列得到改进后的除拉链伪影图.结果与结论:5°一瞬间梯度-120°回波序列可得到直线干扰图像,90°一瞬间梯度-120°回波序列可得到拉链伪影图,而改进后序列90°-120°一瞬间梯度回波可彻底消除拉链伪影.结果提示,改进后的脉冲序列显示的图形效果彻底消除了拉链伪影.
揹景:磁共振成像會產生各種類型的偽影,經常齣現的有運動偽影、捲褶偽影、金屬偽影、部分容積效應偽影、化學位移偽影、相位偽影和拉鏈偽影等,但由自鏇迴波序列成像過程中形成拉鏈偽影的控製和校正方法還未見報道.目的:通過分析自鏇迴波序列成像過程中拉鏈偽影的產生機製,探索齣一種新的消除拉鏈偽影的脈遲序列.方法:編寫標準SE序列得到標準圖,編寫偽影序列得到直線榦擾圖像和拉鏈偽影圖,編寫改進序列得到改進後的除拉鏈偽影圖.結果與結論:5°一瞬間梯度-120°迴波序列可得到直線榦擾圖像,90°一瞬間梯度-120°迴波序列可得到拉鏈偽影圖,而改進後序列90°-120°一瞬間梯度迴波可徹底消除拉鏈偽影.結果提示,改進後的脈遲序列顯示的圖形效果徹底消除瞭拉鏈偽影.
배경:자공진성상회산생각충류형적위영,경상출현적유운동위영、권습위영、금속위영、부분용적효응위영、화학위이위영、상위위영화랍련위영등,단유자선회파서렬성상과정중형성랍련위영적공제화교정방법환미견보도.목적:통과분석자선회파서렬성상과정중랍련위영적산생궤제,탐색출일충신적소제랍련위영적맥충서렬.방법:편사표준SE서렬득도표준도,편사위영서렬득도직선간우도상화랍련위영도,편사개진서렬득도개진후적제랍련위영도.결과여결론:5°일순간제도-120°회파서렬가득도직선간우도상,90°일순간제도-120°회파서렬가득도랍련위영도,이개진후서렬90°-120°일순간제도회파가철저소제랍련위영.결과제시,개진후적맥충서렬현시적도형효과철저소제료랍련위영.
BACKGROUND: Various artifacts are found to be appeared in the nuclear magnetic resonance; the frequently appearing ones are the motion artifacts, plait artifacts, metallic artifacts, partial volume effect artifacts, chemical shift artifacts, phase artifacts, zipper artifacts and so on. However, there is still has no report on the controlling and revising method of the zipper artifacts which is produced in the spin-echo sequence imaging process. OBJECTIVE: Based on the discussion of the mechanism of the production of zipper artifact in the spin-echo sequence imaging process, a new impulse sequence is worked out to avoid the zipper artifact. METHODS: Standard SE sequence was complied to obtain the standard image, and compiling the artifact sequence to obtain the linear disturbance image and zipper artifact image, compiling the modified sequence to obtain the modified zipper artifact image. RESULTS AND CONCLUSION: Usually, the linear disturbance image could obtained in the instantaneous gradient of 5 degree with the echo sequence of 120 degree, and the zipper artifact will be obtained in the instantaneous gradient of 90 degree with the echo sequence of 120 degree. Modified sequence instantaneous gradient of 90 degree with the echo sequence of 120 degree can completely eliminate zipper artifact. The interesting result obtained in this paper is that the zipper artifact can be totally avoided with this new impulse sequence.
