JOURNAL OF BONE AND MINERAL zyxwvuts RESEARCH Volume zyxwvutsrqpo 5, Number 3,1990 Mary Ann Liebert, Inc., Publishers zyxwvutsrqp A New Method for Automatic Recognition of the Radiographic Trabecular Pattern WIL G.M. GERAETS, PAUL F. VAN DER STELT, COEN J. NETELENBOS, and PETRA J.M. ELDERS ABSTRACT This study reports a method to describe and analyze the structure of the trabecular pattern seen on radio- graphs of the distal radius. The structure is measured and related to the bone mineral density (BMD) of the lumbar spine measured by dual-photon absorptiometry. Radiographs of hand and wrist combined with additional information of the bone mineral density of the vertebrae serve as testing material. With a computer-aided imaging system, a part of the depicted radius is scanned. The image is filtered and segmented into a bilevel picture consisting of a light network with dark meshes. Seven features of the bilevel picture are measured and analyzed. It is shown that six features correlate significantly with the bone mineral density measured at the lumbar spine, although the correlations between the trabecular pattern and the BMD are too weak to allow precise predictions of BMD values for individuals. Nevertheless, the correlations confirm the existence of a relation- ship between the radiographic trabecular pattern and the bone mineral density of the lumbar spine. The method is worth being further developed for use on individual patients. It provides a noninvasive tool to make an objective and quantitative assessment of the trabecular pattern. INTRODUCTION OME DISORDERS cause thinning and disappearance of the S bone trabeculae. Postmenopausal osteoporosis shows accelerated loss of trabecular bone. Accelerated lumbar vertebral bone loss related to menopause is an important determinant of postmenopausal osteoporosis. In this type of osteoporosis, fractures of vertebrae and distal ra- dius are mainly found. In men and women 75 years of age and older, another type of osteoporosis, senile osteoporo- sis, can be present with both trabecular and cortical bone loss and fractures of vertebrae and hips.(l) Bone fractures become a real threat to older women, who lose bone mass rapidly in the fiist 8-10 years after menopause. Men, who are endowed with greater bone mass than women, become vulnerable in their seventies and eighties. Bone has a complicated structure. It contains trabeculae that vary widely in shape, size, and thickness. On a radio- graph, bony trabeculae appear to cross one another and to enclose spaces. The trabeculae and the radiolucent areas between them appear ill defined.(31 Although the trabecu- lar pattern on a radiograph resembles the histologic ap- pearance, a clear distinction must be made. It is known that the trabecular pattern on radiographs of the radius originates from the bone structure in the transitional re- gion of cortical and cancellous bone. Trabeculae in the cancellous part of the radius hardly contribute to the ra- diographic image.") In this study we divide the trabecular pattern on a radiograph in two parts. One part resembles a network and appears light. The second part consists of the remaining darker areas of the image, the meshes of the network. Department of Oral Radiology, Academic Center for Dentistry Amsterdam (ACTA), Vrije Universiteit, Amsterdam, The Nether- lands. zyxwvutsrqpo 221