Department of Signal Processing and Communications, Universidad Carlos III de Madrid, Madrid, Spain.
Magn Reson Med. 2010 Mar;63(3):592-600. doi: 10.1002/mrm.22275.
Spatial suppression of peripheral regions (outer volume suppression) is used in MR spectroscopic imaging to reduce contamination from strong lipid and water signals. The manual placement of outer volume suppression slices requires significant operator interaction, which is time consuming and introduces variability in volume coverage. Placing a large number of outer volume saturation bands for volumetric MR spectroscopic imaging studies is particularly challenging and time consuming and becomes unmanageable as the number of suppression bands increases. In this study, a method is presented that automatically segments a high-resolution MR image in order to identify the peripheral lipid-containing regions. This method computes an optimized placement of suppression bands in three dimensions and is based on the maximization of a criterion function. This criterion function maximizes coverage of peripheral lipid-containing areas and minimizes suppression of cortical brain regions and regions outside of the head. Computer simulation demonstrates automatic placement of 16 suppression slices to form a convex hull that covers peripheral lipid-containing regions above the base of the brain. In vivo metabolite mapping obtained with short echo time proton-echo-planar spectroscopic imaging shows that the automatic method yields a placement of suppression slices that is very similar to that of a skilled human operator in terms of lipid suppression and usable brain voxels.
空间抑制外周区域（外体积抑制）用于磁共振波谱成像，以减少来自强脂质和水信号的污染。手动放置外体积抑制片需要大量的操作人员交互，这既耗时又会导致体积覆盖的可变性。为容积磁共振波谱成像研究放置大量的外体积饱和带特别具有挑战性且耗时，并且随着抑制带数量的增加变得难以管理。在这项研究中，提出了一种自动分割高分辨率磁共振图像的方法，以识别含脂的外周区域。该方法在三维空间中计算抑制带的最佳放置位置，并且基于准则函数的最大化。该准则函数最大化了外周含脂区域的覆盖范围，并最小化了皮质脑区和头部外区域的抑制。计算机模拟证明了自动放置 16 个抑制片以形成凸壳，该凸壳覆盖大脑底部上方的含脂外周区域。利用短回波时间质子回波平面波谱成像获得的代谢物图表明，自动方法在抑制脂质和可用于大脑体素方面的抑制片放置与熟练的操作人员非常相似。
