Ruttimann U E, Webber R L, Hazelrig J B
Diagnostic Systems Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, Md.
Oral Surg Oral Med Oral Pathol. 1992 Jul;74(1):98-110. doi: 10.1016/0030-4220(92)90222-c.
The purpose of this study was to investigate whether a radiographic estimate of osseous fractal dimension is useful in the characterization of structural changes in alveolar bone. Ten dry mandibular bone segments were radiographed from three controlled projection angles (-5, 0, +5 degrees), before and after acid-induced partial decalcification. Fractal dimension was estimated by regression analysis of power spectra computed by Fourier transform of selected regions of interest in digitized images of the radiographs. Repeated-measures ANOVA showed that fractal dimension so determined varied over anatomic locations (p less than .01), but increased after acid-induced demineralization (p less than .0005), irrespective of the radiographic projection angles (p greater than .99). In vivo fractal dimension was computed from randomly selected intraoral radiographs of six premenopausal (ages, 32.8 +/- 3.9) and six postmenopausal (ages, 62.5 +/- 4.1) women. A significantly (p less than .01) higher fractal dimension was observed in the older group.
本研究的目的是调查骨分形维数的影像学估计是否有助于表征牙槽骨的结构变化。在酸诱导部分脱钙前后，从三个控制投影角度（-5、0、+5度）对10个干燥下颌骨段进行放射照相。通过对放射照片数字化图像中选定感兴趣区域进行傅里叶变换计算得到的功率谱进行回归分析来估计分形维数。重复测量方差分析表明，如此确定的分形维数在不同解剖位置有所变化（p<0.01），但在酸诱导脱矿后增加（p<0.0005），与放射投影角度无关（p>0.99）。从6名绝经前（年龄，32.8±3.9）和6名绝经后（年龄，62.5±4.1）女性随机选择的口腔内放射照片计算体内分形维数。在老年组中观察到分形维数显著更高（p<0.01）。
