A NEW PROPELLER EPI DESIGN USING SHORT AXIS READOUTS

使用短轴读数的新型螺旋桨 EPI 设计

• 批准号: 7358810
• 负责人: STEFAN SKARE
• 金额: $ 1.25万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7358810
• 关键词: NEW; PROPELLER; EPI; DESIGN; USING

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Introduction EPI suffers from various artifacts such as geometric distortions, Nyquist ghosting, T2* blurring, Maxwell effects and eddy currents (especially for DW-EPI). The magnitude of these artifacts is inversely scaled by the speed of k-space traversal along the phase encoding direction (a.k.a. pseudo bandwidth), which is determined by two factors: a) the time between two consecutive echoes in the EPI readout train and b) the phase field-of-view (FOV Materials and methods A 1.5T GE Excite system equipped with 50 mT/m gradients was used for the experiments. Our proposed SAP-EPI was compared with LAP-EPI w.r.t. blurring due to Nyquist ghosting and susceptibility. To compare the ghosting levels for the individual blades between LAP-EPI and SAP-EPI, a small cylindrical phantom measuring 10 cm in diameter was used with a FOV of 24¿24 cm. The acquired resolutions were 256¿32 (LAP-EPI) and 32¿256 (SAP-EPI) using 25 blades swept from 0 to 180¿. Images were also acquired on a volunteer using conventional ssEPI, LAP-EPI and SAP-EPI, with the same parameters and target resolution of 256¿256. References 1. Pipe JG. Motion correction with PROPELLER MRI: application to head motion and free-breathing cardiac imaging. Magn Reson Med 1999;42(5):963-969. 2. Wang FN, Huang TY, Lin FH, Chuang TC, Chen NK, Chung HW, Chen CY, Kwong KK. PROPELLER EPI: An MRI technique suitable for diffusion tensor imaging at high field strength with reduced geometric distortions. Magn Reson Med 2005;54(5):1232-1240. 3. Chuang TC, Huang TY, Lin FH, Wang FN, Chung HW, Chen CY, Kwong K. Propeller EPI with SENSE parallel imaging using a circularly symmetric phase array RF coil. 2004; Kyoto. p 535. 4. Forbes KP, Pipe JG, Bird CR, Heiserman JE. PROPELLER MRI: clinical testing of a novel technique for quantification and compensation of head motion. J Magn Reson Imaging 2001;14(3):215-222. 5. Grieve SM, Blamire AM, Styles P. Elimination of Nyquist ghosting caused by read-out to phase-encode gradient cross-terms in EPI. Magn Reson Med 2002;47(2):337-343. Acknowledgements This work was supported in part by the NIH (1R01EB002771), the Center of Advanced MR Technology at Stanford (P41RR09784), Lucas Foundation, and Oak Foundation.

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。EPI受到各种伪影的影响，如几何失真、奈奎斯特重影、T2* 模糊、麦克斯韦效应和涡流（特别是对于DW-EPI）。这些伪影的幅度由沿着相位编码方向（也称为沿沿着）的k空间遍历的速度反比例缩放。伪带宽），其由两个因素确定：a）EPI读出序列中两个连续回波之间的时间和B）相位视场（FOV）。材料和方法将配备有50 mT/m梯度的1.5 T GE Excite系统用于实验。将我们提出的SAP-EPI与LAP-EPI进行了比较。模糊由于奈奎斯特重影和磁化率。为了比较LAP-EPI和SAP-EPI之间单个刀片的重影水平，使用直径为10 cm的小型圆柱体模，FOV为24 - 24 cm。使用从0到180 <$$>扫描的25个叶片，获得的分辨率为256 <$32（LAP-EPI）和32 <$256（SAP-EPI）。还使用常规ssEPI、LAP-EPI和SAP-EPI在志愿者上获取图像，具有相同的参数和256 <$256的目标分辨率。 参考文献1.管道JG。PROPELLER MRI运动校正：应用于头部运动和自由呼吸心脏成像。Magn Reson Med 1999;42（5）：963-969。2.王芳芳，黄天义，林丰芳，庄忠昌，陈国康，钟浩华，陈春艳，邝国康。PROPELLER EPI：一种适用于在高场强下进行扩散张量成像的MRI技术，具有减少的几何失真。Magn Reson Med 2005;54（5）：1232-1240。3.庄忠祥，黄天义，林丰芳，王丰芳，钟浩华，陈春英，邝光光。螺旋桨EPI与SENSE并行成像，使用圆形对称相控阵RF线圈。2004年;京都。第535页。4.福布斯KP，Pipe JG，Bird CR，Heiserman JE。PROPELLER MRI：用于头部运动量化和补偿的新技术的临床测试。J Magn Reson Imaging 2001;14（3）：215-222。5. Grieve SM，Blamire AM，Styles P. EPI中相位编码梯度交叉项读出引起的奈奎斯特重影消除。Magn Reson Med 2002;47（2）：337-343。 致谢这项工作得到了NIH（1 R 01 EB 002771）、斯坦福大学先进MR技术中心（P41 RR 09784）、卢卡斯基金会和橡树基金会的部分支持。