CAJ | 학술논문

目的研究层面选择方向扩散加权成像(DWIs)在中脑大脑脚问产生高信号的机制.方法健康志愿者10名,以邻近中脑大脑脚问为中心进行MR扫描:(1)采用心电门控(ECG),测量收缩期与舒张期扩散敏感因子(b值)为0和1000 mm2/s的单独DWIs,比较两期测量中脑亮点区MR信号强度及表观扩散系数(ADC)值.(2)变换选层方向,分别采集平行于颅底、平行于系统Y轴,Y-Z坐标30°夹角的单独DWIs,观察中脑亮点形状的变化.(3)采集全脑6个方向DWI,利用扩散张量成像(DTI)白质纤维束追踪成像技术显示以亮点区为种子的神经纤维束走行起止,测量亮点区及其相连邻近纤维走行区的ADC值与各向异性分数(FA)值.将测量得到的亮点区ADC及FA值与相连邻近纤维走行区的ADC及FA值分别进行配对t检验,比较两者之间的差异.结果心脏收缩期采集的DWIs信号强度分别为296.28±38.19、153.81±37.91,舒张期分别为295.36.±38.84、154.03±37.52,两者间差异无统计学意义(t值分别为1.34、0.62,P值均＞0.05);心脏收缩与舒张期测量的ADC值分别为(6.07±2.20)×10-4、(6.69±1.44)×10-4 mm2/s,两者间差异无统计学意义(t=0.94,P＞0.05).纤维束追踪显示中脑高信号亮点位于小脑上脚神经纤维束的中脑交叉区.常规扫描层面上,DWIs高信号亮点表现为狭长心形和狭长条形,其形状随扩散敏感梯度施加方向的变化而改变.多方向DWI测量亮点区与结合臂区的ADC值分别为(10.61±3.42)×10-4与(9.24±2.21)×10-4 mm2/s,两者间差异无统计学意义(t=0.61,P＞0.05).亮点区FA值为O.43±0.13,结合臂FA值为0.61±0.08,两者间差异有统计学意义(t=8.32,P＜0.05).结论中脑水平DWIs亮点征象由小脑上脚在中脑层面神经纤维及交叉区的各向异性造成,因此,其亮点信号的形状与DWIs的选层层面方向有关,与心动周期相关的脑搏动对亮点征象无影响.
목적 연구층면선택방향확산가권성상(DWIs)재중뇌대뇌각문산생고신호적궤제.방법 건강지원자10명,이린근중뇌대뇌각문위중심진행MR소묘:(1)채용심전문공(ECG),측량수축기여서장기확산민감인자(b치)위0화1000 mm2/s적단독DWIs,비교량기측량중뇌량점구MR신호강도급표관확산계수(ADC)치.(2)변환선층방향,분별채집평행우로저、평행우계통Y축,Y-Z좌표30°협각적단독DWIs,관찰중뇌량점형상적변화.(3)채집전뇌6개방향DWI,이용확산장량성상(DTI)백질섬유속추종성상기술현시이량점구위충자적신경섬유속주행기지,측량량점구급기상련린근섬유주행구적ADC치여각향이성분수(FA)치.장측량득도적량점구ADC급FA치여상련린근섬유주행구적ADC급FA치분별진행배대t검험,비교량자지간적차이.결과 심장수축기채집적DWIs신호강도분별위296.28±38.19、153.81±37.91,서장기분별위295.36.±38.84、154.03±37.52,량자간차이무통계학의의(t치분별위1.34、0.62,P치균＞0.05);심장수축여서장기측량적ADC치분별위(6.07±2.20)×10-4、(6.69±1.44)×10-4 mm2/s,량자간차이무통계학의의(t=0.94,P＞0.05).섬유속추종현시중뇌고신호량점위우소뇌상각신경섬유속적중뇌교차구.상규소묘층면상,DWIs고신호량점표현위협장심형화협장조형,기형상수확산민감제도시가방향적변화이개변.다방향DWI측량량점구여결합비구적ADC치분별위(10.61±3.42)×10-4여(9.24±2.21)×10-4 mm2/s,량자간차이무통계학의의(t=0.61,P＞0.05).량점구FA치위O.43±0.13,결합비FA치위0.61±0.08,량자간차이유통계학의의(t=8.32,P＜0.05).결론 중뇌수평DWIs량점정상유소뇌상각재중뇌층면신경섬유급교차구적각향이성조성,인차,기량점신호적형상여DWIs적선층층면방향유관,여심동주기상관적뇌박동대량점정상무영향.
Objective To study the mechanism of hyperintensed signal at interpeduncle region in meseneephalon on DWI with diffusion sensitive gradient(Gd)applied perpendicular to the slice direetion (DWIs).Methods MRI scanning was centered at interpeduncle region.and the protocols were as follows:(1)With electrocardiograph(ECG)triggering,DWIs was acquired during systole or diastole periods respectively.(2)To observe the shape of hyperintense signal,DWIs with various slice directions was applied,which was set parallel to skull base,along Y axis,or along the oblique line between Y and Z axis with 30°to Z axis.(3)Fiber tracking was performed with the hyperintense signal as"seed"region,fractional anisotropy(FA)and ADC were derived from(multiple directions diffusion weighted imaging,MDDW).FA and ADC of hyperintease region were compared with those of the nearby fiber by using pair t-tesL Results Signal intensitv of hyperintense region on DWIs were 2296.28±38.19 and 153.81±37.91 for b=0 and b=1000 at systole period.while they were 295.36±38.84 and 154.03±37.52 at diastole period.No staffstical difference wag demonstrated between them(t=1.34,0.62,P＞0.05).The ADC valus on DWIs acquired during systole and diastole periods were(6.07±2.20)×10-4and(6.69±1.44)×10-4 mm2/s respectively.There was rio statistical difference between them(t=0.94,P＞0.05).DTI fiber tracking verified that the hyperintense region located at the decussation of superior eerebelum peduncle(SCP)in mesencephalon.It was in long and narrow heart shape or rectangular shape on DWIs.The shape depended on the direction of Gd The ADC value derived from MDDW at hyperintense region and the fiber below were(10.61±3.42)×10-4 and(9.24±2.21)×10-4 mm2/s respectively.No statistical difference was demonstrated between them(t=0.61.P＞0.05).While,the FA at hyperintensed region 0.43±0.13 was less than that of the fiber below 0.61±0.08(t=8.32.P＜0.05).Conclusions The shape of the hyperintense region on DWIs depends on the direction of Gd.The cardiac period has no effects on the hyperintense signal at peduncles,which may be attributed to the anisotropy of SCP decussation in mesencephalon.