Yebin Jiang MD, PhD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: This study was designed to evaluate the precision of micro CT quantitation of three-dimensional (3D) microarchitecture of the trabecular (Tb) and cortical bone in iliac crest bone biopsies. Capturing true longitudinal transmenopausal changes in 3D bone micro architecture may improve our ability to understand the pathophysiology of osteoporosis and other bone disorders, and to estimate the bone biomechanical properties in terms of fracture resistance as the mechanical competence of Tb bone is a function of its apparent density and 3D distribution. During aging and diseases such as osteoporosis, Tb plates are perforated and connecting rods are dissolved, with a continuous shift from one structural type to the other. Such changes can not be evaluated by 2D histological sections. Methods and Materials: We examined 52 paired bone biopsies (102 specimens) from the iliac crest, from osteoporotic postmenopausal women with vertebral osteoporotic fracture treated with placebo or Teriparatide injection (rDNA origin) [rhPTH(1-34)]. The specimens were scanned using a Scanco micro CT with isotropic resolution of 17 µ. 3D structural parameters were directly measured without stereological model assumptions as in 2D histomorphometry. Values of 0 and 3 for the structure model index (SMI) represent a perfect plate structure and an ideal cylindrical rod structure, respectively, while values ranging from 0 to 3 indicate a structure with both plates and rods of equal thickness, depending on the volume ratio of rods and plates. Over 1 year later, 10 paired bone biopsies (20 specimens) from different groups were re-scanned and re-analyzed. The root mean square coefficient of variation (RMSCV) of the Tb and cortical bone 3D microstructural parameters was calculated as a measure of reproducibility. Results: The RMSCV was 2.6% for Tb bone volume fraction (BV/TV), 3.6% for Tb number, 5.9% for Tb thickness, 4.0% for Tb separation, 3.3% for Tb degree of anisotropy, 2.1% for SMI, 3.9% for Tb connectivity density (CD), 2.7% for cortical porosity (Ct.Po), and 2.9% for cortical thickness (Ct.Th). The annualized median percent change in placebo group was -3.3% for BV/TV, 4.6% SMI, -9.2% CD, and -14% Ct.Po, and in Teriparatide treated group 4.7% for BV/TV, -8% SMI, 13% CD, 0.5% for Ct.Po, and 14% Ct.Th. Conclusion: Micro CT can reproducibly quantify 3D microarchitecture of the Tb and cortical bone in the iliac crest biopsy, which may find application in studying pathophysiology of osteoporosis and other bone disorders and evaluating their therapeutic efficacy. (Y.J. received a grant from Lilly Research Laboratories.)

Jiang MD, PhD, Y, Reproducibility of Micro CT Quantification of Three-Dimensional Microarchitecture of the Trabecular and Cortical Bone in the Iliac Crest of Postmenopausal Osteoporotic Women and Their Treatment with Teriparatide [rhPTH(1-34)].  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3105409.html