Does the trabecular bone structure depicted by high-resolution MRI of the calcaneus reflect the true bone structure?

RATIONALE AND OBJECTIVES. The purpose of this study was to compare trabecul ar bone structure parameters assessed with high-resolution magnetic resonan ce imaging (HR-MRI) with those determined in specimen sections, METHODS. High-resolution MR images were obtained for 30 calcaneus specimens with a three-dimensional, T1-weighted spin-echo sequence (spatial in-plane resolution 0.195 mm, slice thicknesses of 0.3 and 0.9 mm), Thirty-eight se ctions were obtained from the specimens, and contact radiography was perfor med, In the corresponding sections, structural parameters analogous to bone histomorphometry were determined. RESULTS. Significant correlations between MRI-derived structural parameters and those derived from macro pathological sections were found: r values of up to 0.75 were obtained (P < 0.01). The highest correlations were found f or apparent bone volume/total volume and trabecular thickness, Image thresh olding techniques showed a significant impact on these correlations (P < 0. 01). The thinner MR sections were less susceptible to the different thresho lding algorithms. CONCLUSIONS. Trabecular bone structure depicted by HR-MR images is signific antly correlated with that shown in macro sections (P < 0.01); however, a n umber of limitations have to be considered, including the substantial impac t of thresholding techniques and slice thickness.