Posse S, Schuknecht B, Smith M E, van Zijl P C, Herschkowitz N, Moonen C T
Diagnostic Radiology Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892.
J Comput Assist Tomogr. 1993 Jan-Feb;17(1):1-14. doi: 10.1097/00004728-199301000-00001.
Proton spectroscopic imaging at short TEs (20-30 ms) in human brain requires volume preselection inside the brain to suppress overwhelming lipid and water signals from surrounding tissue. In this article we discuss limitations of conventional volume preselection using stimulated echoes that lead to spectral contamination from surrounding tissue. Improved volume preselection was obtained by adding a complete outer volume suppression (presaturation). The performance of the method is illustrated on normal volunteers and on clinical cases with brain tumors and multiple sclerosis (MS) plaques. In normal human brain, we detected resonances with short T2 values and complex J-coupling, including rather broad methyl/methylene resonances in the chemical shift range between 0 and 2 ppm. Spectroscopic images obtained on patients with intracranial tumors and on one patient with several MS plaques demonstrate the possibility of detecting regional distributions of increased methyl/methylene resonances between 0 and 2 ppm in brain lesions.
在人脑进行短回波时间（20 - 30毫秒）的质子波谱成像时，需要在脑内进行容积预选择，以抑制来自周围组织的压倒性脂质和水信号。在本文中，我们讨论了使用受激回波进行传统容积预选择的局限性，这种方法会导致来自周围组织的光谱污染。通过添加完整的外容积抑制（预饱和）获得了改进的容积预选择。该方法的性能在正常志愿者以及患有脑肿瘤和多发性硬化症（MS）斑块的临床病例中得到了展示。在正常人类大脑中，我们检测到了具有短T2值和复杂J耦合的共振，包括在0至2 ppm化学位移范围内相当宽的甲基/亚甲基共振。在患有颅内肿瘤的患者和一名患有多个MS斑块的患者身上获得的波谱图像表明，有可能检测到脑病变中0至2 ppm之间甲基/亚甲基共振增加的区域分布。
