METHODS FOR QUANTITATIVE-ANALYSIS OF TRABECULAR BONE-STRUCTURE

Bone mineral density accounts for 70% to 80% of the mechanical resista nce of bone but is unrelated to bone tissue structure. The vertebral f racture risk increases with advancing age irrespective of whether or n ot bone mineral density decreases, suggesting that changes in bone mic roarchitecture contribute significantly to the development of osteopor osis. In contrast to bone mass, bone architecture is difficult to eval uate. Among the various methods developed to investigate bone structur e, biomechanical studies are of limited value since they are done on c adaver bones. Measurement of microarchitectural parameters (e.g., mean trabecular thickness, density and separation) in bone specimens obtai ned by needle biopsy is the gold-standard technique. Parameters reflec ting trabecular interconnections (e.g., total number of nodes and free ends) can also be measured on needle biopsy specimens. New techniques of as yet unproven validity include star volume and trabecular bone p attern factor measurement. Noninvasive techniques capable of supplying qualitative information about bone tissue are also under study. Ultra sonography can theoretically provide data on bone microarchitecture bu t has not yet been proven useful in clinical practice. Statistical, st ructural, or fractal analysis techniques can be used to evaluate bone texture on digitized roentgenograms, computed tomography sections, or magnetic resonance imaging displays; although this approach holds grea t promise, it is still under evaluation and has not yet been compared with histomorphometry. Lastly, the apparent relaxation time of bone ma rrow determined using magnetic resonance imaging may also provide info rmation on bone structure.