The Research On Assessment Of The Osteoporosis And Its Response To The Therapy Using HRMRI

Several studies have indicated that besides bone mineral density (BMD) trabecular architecture may be an equally important factor in assessing bone strength. Magnetic resonance imaging recently has been introduced to the study of trabecular bone architecture . Studies have demonstrated the potential of highresolution MRI to depict the trabecular bone structure and the biomechanical strength of bone Structure measures based on high-resolution MRI were also used in the distal radius to assess changes in trabecular bone architecture in a small number of post-menopausal patients with and without osteoporotic spine fractures and significant differences were shown. High-resolution MRI of the distal radius are suited to predict osteoporotic spine fractures, and the previous results have also to be validated in larger patient populations. The purpose of the present study was as following. Part I. The Experimental Study on Assessing the Trabecular Bone Structure of the Distal Radius with HRMRI Objective: To compare trabecular bone structure parameters obtained from high-resolution magnetic resonance (HRMR) and multislice computed tomography (MSCT) images with those determined in contact radiographs from corresponding specimen sections and exploer the feasibility on assessing the trabecular bone structure of the distal radius with MRI. Methods: High-resolution MR and MSCT images were obtained in 22 distal radius specimens. For HRMR the in-plane spatial resolution was 0.156×0.156 mm~2 with a slice thickness of 0.5mm and 1.0 mm using a 3D T1-weighted spin-echo sequence. For MSCT the resolution was 0.247×0.247 mm~2 with a collimation of 1 mm. Using a diamond saw, 1-mm-thick sections were obtained from these specimens and contact radiographs were acquired. Results: Significant correlations between HRMR-and MSCT-derived structure parameters and those derived from the contact radiographs were found (p<0.01); r values of up to 0.84 were obtained for HRMR imaging and up to 0.73 for MSCT. On the average, structure parameters showed higher correlations for the MR-than for the CT-derived data. Conclusions: Trabecular bone structure parameters assessed in distal radius HRMR images are better then MSCT images,and high-resolution MR-derived structure parameters performed better in the prediction of trabecular bone structure. Part II. The Value on Diagnosing Osteoporosis Using HRMRI Objective: To determine the diagnostic performance of measures of trabecular bone architecture obtained from highresolution MR images of the distal radius in differentiating post-menopausal females with osteoporotic vertebral fractures and normal controls. Methods: HRMR images of the radius were obtained in 11 post-menopausal women with spine fractures and 10 age-matched controls. In every object 15 Images was performed at 1.5 T using a T1-weighted spin-echo sequence (slice thickness 1 mm, in-plane spatial resolution 195×195 μm2). Structure analysis was performed using the special software explored by Soochow University. Bone mineral density of the spine was obtained using quantitative CT Results: Significant differences between both patient groups were obtained with BMD and all structure parameters (p<0.05). Conclusions. The trebecular bone structure measures of the distal radius derived from high-resolution MR images could be used to differentiate post-menopausal patients with spine fractures and healthy age-matched women. The diagnostic performance in differentiating these patients was similar to BMD measures, with the best results obtained for QCT and one of the radius structure measures.This technology can be used gradually in clinic. Part III. The Assessment on the Response to the Osteoporosis Therapy Using HRMRI. Objective: To explore the feasibility of assessing the clinic effect on treating osteoporosis by investigating the bone micro-structure using HRMRI.Methods: There were 11 postmenopausal female patients whose age raged from 55 to 71 years(mean 62.6). All of them had received percutaneous vertebroplasty or kyphoplasty for vertebral compression fracture of T11-L2, and began to walk at the second day postoperation, and took the anti-osteoporotic treatment, and received the check-up of MRI and CT at the third day and 1 year postoperation respectively. Weather patients re-broke their bone had also be recorded. All MRI should be performed in the non-advantaged-side distal radius. We had chosen 4 areas in the distal radius and measured BV/TV, Tb.N, Tb.Sp and Tb.Th in every area respectively with MRI. At the same time, the central vertebral BMD of the L2, L3 and L4 were also measured with QCT. Results: All patients did not recurrent fracture during the 12 mouths follow-up. The BV/TV, Tb.N, Tb.Sp and Tb.Th in MRI of the region of interest (ROI) of the distal radius had changes pre and post-treatment, and the major part had significant difference .The measuring result of the central lumbar vertebral BMD with CT indicated the BMD had increased by 2%, 6%and 5% in L2, L3 and L4 respectively. And there were significant difference in L3 and L4 .The measuring results showed positive correlations between the bone micro-structure of distal radius and lumbar BMD. Conclusions: By measuring trabecular bone structure of in vivo radius with HRMRI the bone quality of lumbar vertebral can be assessed. And the results of HRMRI can provide a complement for evaluating the clinic effect of osteoporosis treatment.