Morphologically extracted trabecular skeleton superimposed upon digital radiograph structure.

The purpose of this study was to employ a morphological filter to digital X-ray images to extract the morphology of trabecular structures in a clearly understandable visual format. This study compares the trabecular skeleton extracted by a morphological filter to the original digital radiographic image by superimposing the images. A morphological filter (a combination of a single structuring element and a skeleton operation) based on a mathematical morphology theory was used to extract the skeletal pattern of trabecular bone from a digital X-ray image of a human femoral neck. Subset images with different operation numbers (n = 1, n = 2) were obtained, and then each image was superimposed on the original digital radiographic image using the superimpose function of a workstation. The extracted trabecular skeleton pattern was fairly consistent with the trabecular structure seen on the digital image according to the opinion of seven dentomaxillofacial radiologists. In their opinion, the majority of the structural elements were reproduced on the extracted skeleton. However, accurate skeleton elements were not extracted in the region of dense trabecular structure. The morphological filter was able to extract a large portion of the bone trabecular structure as a binary skeletal pattern image from trabecular bone on digital X-ray image, but more work is needed to improve the assessment of dense trabeculae.