High resolution T2*-weighted Magnetic Resonance Imaging at 3 Tesla using PROPELLER-EPI

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.     

一种提高CT诊断床板承载能力的方法与应用

在CT诊断床板的承载能力试验中,通过对床板中易产生破坏区域及相关测试数据的分析,在床板局部区域采用了简单的机械辅助支撑结构方式,解决了床板承载强度不足的问题并在实际产品使用中取得了显著的成效。     

实时超声-X线透视图像融合技术研究及应用进展

X线透视成像与超声成像优势互补,同时显示两种图像,可精确可视化手术器械及软组织结构,现已广泛用于心脏介入手术;但需要多个屏幕及操作人员高度配合。实时超声-X线透视图像融合技术能有效解决相关问题。本文对实时超声-X线透视图像融合技术研究及应用进展进行综述。