Biomedical subjects
Publications and source records attributed to B Roos.
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The bone mineral content of 109 lumbar vertebrae from 36 different subjects was determined by dual photon absorptiometry. The mean age of the subjects was 58.5 years (range, 31 to 79 years). The ultimate strength of the vertebral bodies was determined during axial compression. Bone mineral content and ultimate compressive strength were correlated (r = 0.86) and the strength was found to increase linearly with increasing amounts of bone mineral content. No differences in this correlation were found in the four vertebral levels (L-4) included in the study, but a difference in this correlation was found between specimens taken from male and female subjects. The results make it possible to estimate the strength of a vertebral body from the knowledge of its bone mineral content as determined by dual photon absorptiometry and provide a basis of estimations of normal and abnormal amounts of bone mineral content in the vertebrae of the lumbar spine.
The bone mineral content of 109 excised lumbar vertebrae from 21 female subjects (aged 34 to 74 years) and 15 male subjects (aged 31 to 79 years) was determined with dual photon absorptiometry. It was correlated with the age, height, and weight of the subjects and with the body weight above each vertebra. No correlation was found between the bone mineral content and the lumbar spine score of Barnett and Nordin. The bone mineral content determined with dual photon absorptiometry was also correlated with the weight of fresh and ashed bone cubes removed from the interior of 40 of the aforementioned vertebrae selected at random. The bone mineral content decreased with increasing age and at a similar rate within the ages studied in both sexes. The findings indicated that pathologic demineralization in the elderly could be the result of low bone mineral content early in life, and more frequently so in female vertebrae.
The bone mineral content and the ultimate compressive strength were determined in 109 fresh lumbar vertebrae from 36 different subjects, 31 to 79 years of age. The degree of macroscopic disc degeneration and the types of fracture were determined. Three types of fracture-central, wedge and transverse-were found, but only under magnification and at simultaneous movements of the fracture segment. The central type of fracture was found predominantly in specimens with high bone mineral content surrounded by normal discs. The wedge type of fracture was consistent with lower bone mineral content and more severe disc degeneration.
The bone mineral content of 109 lumbar vertebrae was related to the number of trabecular microcalluses in the vertebral bodies. The appearance and location of the calluses were also investigated. Microcalluses were found in 87 of the vertebral bodies. The incidences of calluses varied in the different groups (31-79 years) between 60 and 90%. The number of calluses increased with decreasing bone mineral content. The location of the calluses corresponded to the location of experimental in vitro compression fractures of the vertebral bodies.
A new technique for determination of the bone mineral content in the vertebral body by means of a laterally directed roentgen ray beam is presented. By using a stable high voltage for the roentgen tube and a stable detector with very high energy resolution, the amount of bone mineral in the path of the radiation beam can be determined with correction for both fat and lean soft tissue. The results so far indicate that the technique is useful for objective determination of the bone mineral content in the vertebral body.
The feasibility of determination of bone mineral content using a triple-photon absorptiometric technique is presented. Using three different photon energies it is possible to correct the measured 'bone mineral' value for fat and lean soft tissue. The theoretical basis of the method, as well as the experimental determination of mass attenuation coefficients, is described. It is shown that the results are reproducible within 5 per cent, which means that the method could be of value in the management of metabolic bone diseases.