Comparison between radial bone mineral density measured by single photon absorptiometry and histomorphometric bone mass parameters measured on iliac crest biopsies

Summary Bone mineral density (BMD) measured by single photon absorptiometry (SPA) with a Moolsgard 1100^® device on the distal and proximal part of the radius was compared with histomorphometric parameters measured on iliac crest biopsies in 37 patients suffering from various bone disorders. In the whole population, a good correlation was observed between the cancellous bone volume (Cn-BV/TV) measured on iliac crest biopsies and BMD from both the proximal part of the radius (r=0.76, p < 0.001) and the distal part of the radius (r=0.73, p < 0.001). Significant, although weaker correlations, were also found between the cortical width and the BMD from the distal part (r=0.37, p < 0.001) and the proximal part (r=0.44, p < 0.001) of the radius. In the 14 untreated osteoporotic patients, only a significant Spearman correlation was observed between the iliac Cn-BV/TV and the proximal radial BMD (r=0.69, p < 0.05). It is thus not clear, whether radial proximal BMD correctly indicates cortical bone density in osteoporotic patients or not. The large internal variability of each of the two investigated methods and the small group of osteoporotic patients might explain the lack of correlation between the two methods in this group.