ON THE FRACTAL NATURE OF TRABECULAR STRUCTURE
ON THE FRACTAL NATURE OF TRABECULAR STRUCTURE
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DOI：
10.1118/1.597263
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发表时间：
1994-10-01
期刊：
影响因子：
3.8
通讯作者：
WEHRLI, FW
中科院分区：
文献类型：
--
作者：
CHUNG, HW;CHU, CC;WEHRLI, FW
最近有人提出分形分析[Med.Phys.20，1611-1619（1993）]作为一种通过使用盒计数算法测量分形维数来表征松质骨结构的手段。这项工作重新审视可能的分形性质的松质骨的核磁共振（NMR）图像上的结构，通过估计在各种实验条件下的箱尺寸的函数的小梁边界长度。在高分辨率图像（像素大小的顺序为50 μ m）和信噪比为30，小梁边界原来是一个光滑的表面相对于可实现的分辨率，因此是非分形。小梁结构的分形维数是不确定的，并且可以作为图像信噪比的函数而显著变化。本工作进一步表明，“表观”分形维数得到的盒计数是一个反映骨髓孔隙大小。总之，结果表明，在目前可实现的分辨率，盒计数算法是不适合的松质骨的图像分形分析和先前报道的小梁网络的分形外观是人为的。
Fractal analysis has recently been suggested [Med. Phys. 20, 1611-1619 (1993)] as a means to characterize the structure of cancellous bone by measuring the fractal dimension using a box counting algorithm. This work re-examines the possible fractal nature of such structures on nuclear magnetic resonance (NMR) images of cancellous bone by estimating the trabecular boundary length as a function of box size under various experimental conditions. On high-resolution images (pixel sizes on the order of 50 mu m) and signal-to-noise ratios of 30, the trabecular boundary turns out to be a smooth surface relative to the achievable resolution and is thus nonfractal. The fractal dimension of the trabecular structure is undefined and can vary significantly as a function of image signal-to-noise ratio. The present work further indicates the ''apparent'' fractal dimension obtained by box counting to be a reflection of marrow pore size. In conclusion, the results indicate that, at the currently achievable resolution, the box counting algorithm is not suitable for fractal analysis on images of cancellous bone and that the fractal appearance of the trabecular network reported previously is artifactual.