Gersonde K, Tolxdorff T, Felsberg L
Magn Reson Med. 1985 Aug;2(4):390-401. doi: 10.1002/mrm.1910020407.
T2-selective proton imaging at 10 MHz is based on a Carr-Purcell-Meiboom-Gill pulse sequence with at least 36 echoes and 2 tau greater than or equal to 6 ms employing the projection reconstruction technique. The transverse magnetization decay of the volume elements is multiexponential composed of up to three monoexponential T2 components. The T2 values are arranged in T2 histograms which are slice specific. T2 windows are defined in the T2 histogram and used for imaging and for selecting T2 values which are assigned to proton classes and tissues. Tissue characterization is based on the visualization of differences in T2 behavior. The T2 values are transformed into 256 gray levels or, by use of a red-green-blue lookup table, into a rainbow code. Two display techniques have been developed and implemented in the RWTH Aachen Magnetic Resonance Software System (RAMSES): (i) for nonselective T2 imaging with secondary T2 selection and encoding of molecular classes on the basis of T2 values; (ii) for T2-selective imaging by employing combined primary and secondary T2 selection and encoding particular tissues and variations therein. The tissues can be identified by selecting different classes of molecules, like water, lipids, and proteins, when shifting the primary T2 window on the T2 axis of the T2 histogram.
10兆赫兹的T2选择性质子成像基于Carr-Purcell-Meiboom-Gill脉冲序列，具有至少36个回波且2τ大于或等于6毫秒，并采用投影重建技术。体素的横向磁化衰减是多指数的，由多达三个单指数T2分量组成。T2值排列在特定切片的T2直方图中。在T2直方图中定义T2窗口，并用于成像以及选择分配给质子类别和组织的T2值。组织表征基于T2行为差异的可视化。T2值被转换为256个灰度级，或者通过使用红绿蓝查找表，转换为彩虹编码。已经开发并在亚琛工业大学磁共振软件系统（RAMSES）中实现了两种显示技术：（i）用于基于T2值进行二次T2选择和分子类别编码的非选择性T2成像；（ii）通过采用一次和二次T2选择相结合并对特定组织及其变化进行编码的T2选择性成像。当在T2直方图的T2轴上移动一次T2窗口时，可以通过选择不同类别的分子（如水、脂质和蛋白质）来识别组织。
