磁共振成像序列及应用-杨正汉ppt课件.ppt

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1、回波回波1回波回波2回波回波5回波回波4K频率K相位回波回波390回波1回波2回波5回波4回波3180 180 180180 18090ESETL5有效TETR90回波1回波2回波5回波4回波3180 180 180180 18090ESETL5有效TETR100%时间（时间（ms）TE1TE2TE3TE4TE5回波1强度回波2强度回波3强度回波4强度回波5强度 ：90回波1回波2回波5回波4回波3180 180 180180 18090ESETL5有效TETR100%时间（时间（ms）TE1TE2TE3TE4TE5回波1强度回波2强度回波3强度回波4强度回波5强度90回波1回波2回波5回波4

2、回波3180 180 180180 1809090回波1回波2回波5回波4回波3145 160 170175 18090SS-TSE MRCPNXHASTE-T2WI，单层扫描时间单层扫描时间0.8秒秒HASTE-T2WI，单层扫描时间单层扫描时间0.8秒秒NXIR-HASTE T1WITI = 800msTE = 20 msTA= 600 ms激发角度越大，纵向弛豫所需时间越长激发角度越大，T1成分越大，T1对比越大90度脉冲能产生最大的横向磁化矢量180度脉冲产生反向的纵向磁化矢量纵向磁化矢量纵向磁化矢量纵向磁化矢量纵向磁化矢量40km/h50km/h翻转恢复序列结构图FID纵向磁化矢量纵

3、向磁化矢量注意注意：100%100%50%100%50%70%100%50%70%35%100%50%70%35%65%100%50%70%35%65%32.5%60度脉冲度脉冲60度脉冲度脉冲60度脉冲度脉冲离相位梯度聚相位梯度右右左左100%50%37%20%时间（时间（ms）MxyT2*T2T2*(GRE)GRE回波SE回波l扰相梯度回波（扰相梯度回波（Spoiled GRE）l真实稳态进动快速成像（真实稳态进动快速成像（True FISP）l磁化准备梯度回波序列（磁化准备梯度回波序列（MP GRE）：l临床应用：l造影剂造影剂Gd-DTPA0.2ML/KG3ML/SECOND高压注射器

4、或手推高压注射器或手推l扫描时刻扫描时刻动脉期动脉期15-17秒秒门脉期门脉期50-70秒秒平衡期平衡期3-5分钟分钟延时扫描（具体）延时扫描（具体）l填充填充K空间中央空间中央区域的相位编码区域的相位编码线决定图像的对线决定图像的对比比l填充填充K空间周边空间周边区域的相位编码区域的相位编码线决定图像的解线决定图像的解剖细节剖细节5182251520T2WI+FSSPGR T1WIFS动脉期动脉期CT动脉期动脉期lFLASH-T1WI序列用于显示关节软骨可采用序列Fast Imaging Employing Steady State Acquisition临床应用：FIESTA-CINE v

5、s. FASTCINE. FASTCINEFIESTA-CINElong axis viewsshort axis viewImages courtesy of Franz Volhard Klinik, Berlin, GermanyEXITHOMEPREVIOUS INNOVATIONS inCardiovascular MRDr. Daisy ChienSiemens Medical SolutionsErlangen, GermanyDr. Debiao Li, Northwestern University, Chicago3D Volumetric Coverage in 20 s

6、ec3D True-FISP in a Breath-holdNon-enhancementResolution: 1.0 0.7 2.0 mm3 V. Deshpande, D. Li, NWU, ChicagoLMAnomalous RCA originVisualization of Anomalous Coronary ArteryLeft coronary arteries Right coronary arteryRCALADLADRCACourtesy of Northwestern University Hospital, ChicagoRichard McCarthy, MD

7、, Debiao Li, PhD, NWU MRA conventional angiographyComparison: MRA vs. Conventional AngioStenosis in a branch vesselof the circumflex coronary arteryMyocardial Viabilityfast and robustdetection of infarctsNorthwestern University, ChicagoViability StudyMR can predict which patient will benefit from re

8、vascularizationClinical Predictive Value in Patient ManagementTransmural Extent of HyperenhancementWall Motion ImprovementNew England Journal of Medicine, Feb 19 issueCourtesy of ERESA Imaging Center, Valencia, Spain-5005010015020025030015913172125293337414549535761时间（秒）净增信号强度（A U ）系列1系列2系列3-5005010

9、01502002503001357911131517192123252729313335373941434547495153555759时间( 秒)净增信号强度( A U )系列1系列2系列3MS-EPIEXITHOMENEXTPREVIOUSImages courtesy of ICT, Woodbury, NY, USA MR perfusion imaging during stress and at rest using FastCard-ET acquisition Total exam time 20min Ischemic region observed in the inferioseptal wall Results confirmed by Nuclear and Cath examinationsMR Stress Perfusion Study Ischemic Region Caused by RCA DiseaseEXITHOMENEXTPREVIOUS（2）EPI-T2*WI（）T2WIDTIHealthy VolunteerDr. Ma, PLA301, Beijing