Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Philosophenweg 3, 07743 Jena, Germany.
Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Philosophenweg 3, 07743 Jena, Germany.
Z Med Phys. 2014 May;24(2):164-73. doi: 10.1016/j.zemedi.2013.12.003. Epub 2014 Jan 16.
We report the application of PROPELLER-EPI for high resolution T2()-weighted imaging with sub-millimeter in-plane resolution on a clinical 3 Tesla scanner. Periodically rotated blades of a long-axis PROPELLER-EPI sequence were acquired with fast gradient echo readout and acquisition matrix of 320 × 50 per blade. Images were reconstructed by using 2D-gridding, phase and geometric distortion correction and compensation of resonance frequency drifts that occurred during extended measurements. To characterize these resonance frequency offsets, short FID calibration measurements were added to the PROPELLER-EPI sequence. Functional PROPELLER-EPI was performed with volunteers using a simple block design of right handed finger tapping. Results indicate that PROPELLER-EPI can be employed for fast, high resolution T2()-weighted imaging provided geometric distortions and possible resonance frequency drifts are properly corrected. Even small resonance frequency drifts below 10 Hz as well as non-corrected geometric distortions degraded image quality substantially. In the initial fMRI experiment image quality and signal-to-noise ratio was sufficient for obtaining high resolution functional activation maps.
我们报告了在临床 3T 扫描仪上应用 PROPELLER-EPI 进行高分辨率 T2()-加权成像的情况，其在平面内的分辨率达到亚毫米级。使用快速梯度回波读出和每个叶片 320×50 的采集矩阵来采集长轴 PROPELLER-EPI 序列的周期性旋转叶片。通过使用 2D 网格、相位和几何失真校正以及对在扩展测量过程中发生的共振频率漂移进行补偿，来重建图像。为了描述这些共振频率偏移，在 PROPELLER-EPI 序列中添加了短 FID 校准测量。使用右手手指敲击的简单块设计，对志愿者进行了功能 PROPELLER-EPI 实验。结果表明，只要正确校正几何失真和可能的共振频率漂移，PROPELLER-EPI 就可用于快速、高分辨率 T2()-加权成像。即使低于 10Hz 的小共振频率漂移以及未经校正的几何失真也会严重降低图像质量。在最初的 fMRI 实验中，图像质量和信噪比足以获得高分辨率的功能激活图。
