Herndon R C, Lancaster J L, Giedd J N, Fox P T
Department of Radiology and Research Imaging Center, The University of Texas Health Science Center at San Antonio, USA.
J Magn Reson Imaging. 1998 Sep-Oct;8(5):1097-105. doi: 10.1002/jmri.1880080515.
We accurately measured white matter (WM) and gray matter (GM) from three-dimensional (3D) volume studies, using a fuzzy classification technique. The new segmentation method is a modification of a recently published method developed for T1 parametric images. 3D MR images were transformed into pseudo forms of T1 parametric images and segmented into WM and GM voxel fraction images with a set of standardized fuzzy classifiers. This segmentation method was validated with synthesized 3D MR images as phantoms. These phantoms were developed from cryosectioned human brain images located in the superior, middle, and inferior regions of the cerebrum. Phantom volume measurements revealed that, generally, the difference between measured and actual volumes was less than 3% for 1.5-mm simulated brain slices. The average cerebral GM/WM ratio calculated from 3D MR studies in four subjects was 1.77, which compared favorably with the estimate of 1.67 derived from anatomical data. Results indicate that this is an accurate and rapid method for quantifying WM and GM from Tl-weighted 3D volume studies.
我们使用模糊分类技术，从三维（3D）体积研究中准确测量了白质（WM）和灰质（GM）。新的分割方法是对最近发表的针对T1参数图像开发的方法的改进。3D磁共振成像（MR）被转换为T1参数图像的伪形式，并通过一组标准化的模糊分类器分割为WM和GM体素分数图像。这种分割方法用合成的3D MR图像作为模型进行了验证。这些模型是根据位于大脑上、中、下区域的冷冻切片人脑图像开发的。模型体积测量显示，一般来说，对于1.5毫米模拟脑切片，测量体积与实际体积之间的差异小于3%。从四名受试者的3D MR研究中计算出的平均脑GM/WM比率为1.77，与从解剖数据得出的1.67的估计值相比具有优势。结果表明，这是一种从T1加权3D体积研究中量化WM和GM的准确且快速的方法。
