Low-dose and sparse sampling MDCT-based femoral bone strength prediction using finite element analysis
基于低剂量稀疏采样 MDCT 的有限元股骨骨强度预测
- 作者列表："Rayudu, Nithin Manohar","Anitha, D. Praveen","Mei, Kai","Zoffl, Florian","Kopp, Felix K.","Sollmann, Nico","Löffler, Maximilian T.","Kirschke, Jan S.","Noël, Peter B.","Subburaj, Karupppasamy","Baum, Thomas
Summary This study aims to evaluate the impact of dose reduction through tube current and sparse sampling on multi-detector computed tomography (MDCT)-based femoral bone strength prediction using finite element (FE) analysis. FE-predicted femoral failure load obtained from MDCT scan data was not significantly affected by 50% dose reductions through sparse sampling. Further decrease in dose through sparse sampling (25% of original projections) and virtually reduced tube current (50% and 25% of the original dose) showed significant effects on the FE-predicted failure load results. Purpose To investigate the effect of virtually reduced tube current and sparse sampling on multi-detector computed tomography (MDCT)-based femoral bone strength prediction using finite element (FE) analysis. Methods Routine MDCT data covering the proximal femur of 21 subjects (17 males; 4 females; mean age, 71.0 ± 8.8 years) without any bone diseases aside from osteoporosis were included in this study. Fifty percent and 75% dose reductions were achieved by virtually reducing tube current and by applying a sparse sampling strategy from the raw image data. Images were then reconstructed with a statistically iterative reconstruction algorithm. FE analysis was performed on all reconstructed images and the failure load was calculated. The root mean square coefficient of variation (RMSCV) and coefficient of correlation ( R ^2) were calculated to determine the variation in the FE-predicted failure load data for dose reductions, using original-dose MDCT scan as the standard of reference. Results Fifty percent dose reduction through sparse sampling showed lower RMSCV and higher correlations when compared with virtually reduced tube current method (RMSCV = 5.70%, R ^2 = 0.96 vs. RMSCV = 20.78%, R ^2 = 0.79). Seventy-five percent dose reduction achieved through both methods (RMSCV = 22.38%, R ^2 = 0.80 for sparse sampling; RMSCV = 24.58%, R ^2 = 0.73 for reduced tube current) could not predict the failure load accurately. Conclusion Our simulations indicate that up to 50% reduction in radiation dose through sparse sampling can be used for FE-based prediction of femoral failure load. Sparse-sampled MDCT may allow fracture risk prediction and treatment monitoring in osteoporosis with less radiation exposure in the future.
摘要本研究旨在利用有限元 (FE) 分析评估通过管电流和稀疏采样减少剂量对基于多探测器计算机断层扫描 (MDCT) 的股骨骨强度预测的影响。通过稀疏采样，从 MDCT 扫描数据获得的 FE 预测的股骨失效载荷不受 50% 剂量减少的显著影响。通过稀疏采样进一步减少剂量 (原始投影的 25%) 和几乎减少的管电流 (原始剂量的 50% 和 25%) 对 FE 预测的失效载荷结果显示出显著影响。目的探讨几乎减少的管电流和稀疏采样对使用有限元 (FE) 分析的基于多探测器计算机断层扫描 (MDCT) 的股骨骨强度预测的影响。方法 21 例受试者 (男性 17 例; 女性 4 例; 平均年龄 71.0 ± 8.8 岁) 的常规 MDCT 数据覆盖股骨近端除骨质疏松外，无任何骨病者纳入本研究。通过虚拟降低管电流和应用原始图像数据的稀疏采样策略，实现了 75% 和的剂量减少。然后用统计迭代重建算法重建图像。对所有重建图像进行 FE 分析，计算失效载荷。计算均方根变异系数 (RMSCV) 和相关系数 (R ^ 2)，以确定剂量减少的 FE 预测失效载荷数据的变异, 以原始剂量 MDCT 扫描为参考标准。结果与几乎降低的管电流法相比，稀疏采样 5.70% 剂量降低的 RMSCV 较低，相关性较高 (RMSCV = 0.96，R ^ 2 = vs。 rmscv = 20.78%，R ^ 2 = 0.79)。通过两种方法实现的 70-5% 剂量减少 (对于稀疏采样，rmscv = 22.38%，R ^ 2 = 0.80; rmscv = 24.58%, R ^ 2 = 0.73 (管电流减小) 不能准确预测失效载荷。结论我们的模拟表明，通过稀疏采样辐射剂量减少 50% 可用于基于 FE 的股骨失效载荷预测。稀疏采样 MDCT 可能允许在未来辐射暴露较少的骨质疏松症中进行骨折风险预测和治疗监测。
METHODS::Apparent calcium absorption, total bone mineral content and density, and mineral contents of the right femur were studied using a growing rat model. Twenty-four male Wistar rats were fed with diets based on extruded whole grain red (RSD) or white sorghum (WSD), and control diet (CD) up to 60 days. The animals fed with sorghum diets consumed less and gained less weight compared to those fed with CD, but the efficiency of all diets was similar. Calcium intake was lower in animals fed with sorghum diets, related to the lower total intake of these animals. Apparent calcium absorption in animals fed with RSD was lower than in those fed with CD (CD: 72.7%, RSD: 51.0%, WSD: 64.8%). No significant differences in bone mineral density of total body, spin, femur, distal femur, tibia and proximal tibia were observed among the groups. However, Ca and P contents in the right femur of the rats consuming RSD were lower, indicating a certain imbalance in the metabolism of these minerals.
METHODS:OBJECTIVE:Controversy exists about the impact of bone mineral density (BMD) and fracture risk in newly diagnosed patients with breast cancer (BC). It is presumed that there are differences in BMD between women with BC and healthy controls. BMD is therefore considered as a potential marker to predict BC risk. This study was conducted to investigate the association of BMD, trabecular bone score (TBS) and fracture risk in younger postmenopausal women with hormone responsive BC. METHODS:Overall, 343 women were examined. Women with BC were matched to a control group of the general population. Forty-nine women and fifty-nine controls were included in the final analysis. All subjects underwent dual energy x-ray absorptiometry (DXA) of the lumbar spine, femoral neck, and the total hip to evaluate bone mineral density. The 10-year fracture risk for a major osteoporotic fracture was assessed using the FRAX-score and the TBS-adjusted FRAX-Score, respectively. RESULTS:Lumbar and femoral neck BMD were similar in BC patients and controls. No difference was found for TBS of the spine (1.38 ± 0.1 vs.1.36 ± 0.09) in the BC and the control group, respectively (p = 0.19). The 10- year probability for a major osteoporotic fracture (MoF) or femoral neck (FN) fracture was 6.1 (± 2.6%) and 0.9 (± 1.2%) in the BC group vs. 6.7 (± 3.5%) (p = 0.33) and 0.9 (± 1.1%) (p = 0.73) in the control group. CONCLUSION:Postmenopausal women younger than 60 years with breast cancer do not show any differences in baseline BMD, TBS, or TBS adjusted FRAX in comparison to controls.
METHODS::The goals of this study are to evaluate the ability of the multicomponent collagen-elastin-like polypeptide (ELP)-Bioglass scaffolds to support osteogenesis of rat mesenchymal stem cells (rMSCs), demonstrate in vivo biocompatibility by subcutaneous implantation in Sprague-Dawley rats, monitor degradation noninvasively, and finally assess the scaffold's ability in healing critical-sized cranial bone defects. The collagen-ELP-Bioglass scaffold supports the in vitro osteogenic differentiation of rMSCs over a 3 week culture period. The cellular (rMSC-containing) or acellular scaffolds implanted in the subcutaneous pockets of rats do not cause any local or systemic toxic effects or tumors. The real-time monitoring of the fluorescently labeled scaffolds by IVIS reveals that the scaffolds remain at the site of implantation for up to three weeks, during which they degrade gradually. Micro-CT analysis shows that the bilateral cranial critical-sized defects created in rats lead to greater bone regeneration when filled with cellular scaffolds. Bone mineral density and bone microarchitectural parameters are comparable among different scaffold groups, but the histological analysis reveals increased formation of high-quality mature bone in the cellular group, while the acellular group has immature bone and organized connective tissue. These results suggest that the rMSC-seeded collagen-ELP-Bioglass composite scaffolds can aid in better bone healing process.