Evaluation of cancellous structure in the distal radius using spectral analysis.

A preliminary study was conducted to analyze trabecular patterns in digitized wrist radiographic images from 68 patients (31 males and 37 females), aged from 7 to 93 years. The fast Fourier transform was used to perform the spectral analysis of the distal radius. Three indices were defined to permit quantification of the cancellous structure in terms of the spacing and orientation of bone trabeculae (periodicity): a spectral trabecular index, a longitudinal trabecular index, and a transverse trabecular index. The spectral trabecular index reflects the periodicity of the trabeculae (spacing and orientation), while the other 2 selectively reflect the periodicity of longitudinally and transversely oriented ones. The ratio of the longitudinal and transverse trabecular indices was also studied. The shape of the high magnitude frequencies in the spectrum was crosslike for all patients, implying a preferentially orthogonal 2-dimensional structure for the cancellous bone in the distal end of the radius. The variation of the defined trabecular bone indices with age corresponded with the formation of bone through infancy and adolescence, reaching a peak in adulthood and gradual loss thereafter. This quantification detects structural changes that occur with aging and may therefore be useful in the study of osteoporosis.