Radiographic Trabecular Quantitation of Human Lumbar Vertebrae in Situ: I. Theory and Method for Study of Osteoporosis

A scanning microdensitometer-analog computer system is described which permits quantitation of radiographically recorded vertically and horizontally oriented trabecular shadows of in situ human lumbar vertebrae. The basis for vertebral trabecular quantitation in the study of osteoporosis is that trabecular bone is metabolically more active than is cortical bone and vertebral trabecular bone appears to be the most active trabecular bone of the human body in terms of mineral turnover rate. The method for determining the widths and number of radiographically visualized trabeculae is based upon the observation that, when viewed from the lateral projection, the vertically and horizontally oriented trabeculae have a fairly uniform spatial orientation. The method of quantitation yields data which shows reasonable replication and which appears to reflect the visually assessed character of the trabecular pattern.