去势法联合皮质激素快速诱导兔骨质疏松模型

目的探讨去势法联合皮质激素快速诱导骨质疏松(OP)模型兔的可行性。材料与方法 40只8月龄雌性大白兔随机分为假手术组(A组,n=20)及去势+肌注甲强龙组(B组,n=20)。术后第2、4、8、10周行血清骨代谢标志物检测及离体L5椎体显微CT(Micro-CT)扫描。结果两组骨密度(BMD)在OVX术后第8周开始差异有统计学意义,而骨体积分数(BV/TV)、骨小梁连接密度(Conn.D)、骨小梁数目(Tb.N)、结构模型指数(SMI)、骨小梁间隙(Tb.Sp)及骨小梁厚度(Tb.Th)分别在术后4、8周开始差异有统计学意义。结论去势联合肌注甲强龙可在8周内快速建立OP兔模型,骨微结构参数变化早于BMD降低。     

不同强度运动与雌激素联合作用对去卵巢大鼠股骨上端超微结构影响的扫描电镜观察

目的 :探讨不同强度运动与雌激素联合作用对去卵巢大鼠股骨上端超微结构的影响。方法 :成年雌性SD大鼠分为正常对照组 (SHAM )、骨质疏松对照组 (OVX)、雌激素对照组 (OVX +ES)、中等强度运动组 (OVX +EX1)、大强度运动组 (OVX +EX2 )、中等强度运动加雌激素组 (OVX +ES +EX1)和大强度运动加雌激素组 (OVX +ES +EX2 )。用扫描电镜观察 8周不同强度运动及运动和雌激素结合对股骨上端松质骨的影响。结果 :与骨质疏松对照组比 ,中等强度运动组股骨上端骨量增多、保持更好的微结构 ,而大强度运动组骨量及空间结构无变化。两个运动加雌激素组股骨上端骨小梁数量较两个单纯运动组、雌激素对照组及骨质疏松对照组增多 ,骨小梁表面吸收面减少 ,胶原排列规律、整齐。结论 :中等强度运动对去卵巢大鼠股骨上端骨量和骨微结构产生良好影响 ,而大强度运动的影响依赖于是否补充雌激素 :当去卵巢大鼠补充雌激素时大强度运动对骨量及骨结构产生积极作用 ,当去卵巢大鼠缺乏雌激素时大强度运动产生副作用。     

低强度超声理疗防治犬下颌骨放射性骨坏死

目的 探讨低强度超声对犬下颌骨骨组织放射线损伤的修复作用,为临床防治颌骨放射性坏死提供新思路. 方法 建立下颌骨放射线损伤的动物模型,并用低强度超声对其进行治疗,通过微血管密度检测、Micro - CT、丽春红三色染色等观察低强度超声治疗组(实验Ⅱ组)与未用低强度超声治疗组(实验Ⅰ组),并与对照组进行比较. 结果 成功建立放射线损伤的动物模型.实验Ⅱ组微血管密度大于实验Ⅰ组.实验Ⅱ组骨小梁的骨体积分数、骨小梁厚度、骨表面积和骨体积的比值和骨小梁数量大于实验Ⅰ组(P＜0.05).丽春红三色染色可见实验Ⅰ组骨细胞大部分消失,松质骨小梁萎缩;实验Ⅱ组见大量骨质形成,形成越来越多的骨小梁,骨小梁边沿可见大量成骨细胞. 结论 低强度超声对放射线照射后的骨组织具有较好的修复作用.     

骨形态结构的影像学研究方法

骨密度并不能完全反映骨的强度,骨的几何形态、微结构、骨质量等也是骨强度的决定因素,骨的形态结构变化对反映骨强度和预测骨折危险也有重要作用。主要介绍骨的形态结构及小梁微结构的影像学研究和分析方法以及各种方法对骨强度和骨折风险的预测作用。     

骨形态结构的影像学研究方法

骨密度并不能完全反映骨的强度,骨的几何形态、微结构、骨质量等也是骨强度的决定因素,骨的形态结构变化对反映骨强度和预测骨折危险也有重要作用.主要介绍骨的形态结构及小梁微结构的影像学研究和分析方法以及各种方法对骨强度和骨折风险的预测作用.     

原发性骨质疏松症研究进展

骨质疏松症(osteoporosis,简称OP)是以单位体积内骨量减少、骨的微结构退化、骨皮质变薄、骨小梁数目减少、骨髓腔增宽、骨强度减低、易于骨折等为特征的系统性骨病.它是机体自然衰退、老化过程的组成部分,是老年患者致残和致死的一种常见原因,严重影响着老年人群的生存质量.本文讨论了骨质疏松的致病因素、分类、诊断、预防及治疗等方面的研究进展,供临床参考.     

去负荷对大鼠骨计量学和骨质的影响

目的 观察去负荷对骨质显微结构的影响，并对骨小梁的结构进行定量化评定，探讨去负荷骨局部因子、骨强度及骨量的变化。方法 将SD雄性大鼠分为2组，对照组(FAC)和悬吊组(SC)，每组9只，实验期为21d。观察大鼠骨小梁的显微结构，骨中局部因子，骨力学性能及骨量的变化。结果 悬吊组骨小梁结构紊乱，骨小梁面积比(％ Tb．Ar)、骨小梁厚度(Tb．Th)、成骨表面(Ob．S)均显著下降，骨小梁间隙(Tb．Sp)显著增加，破骨细胞数(Oc．N)无显著变化；骨中碱性磷酸酶(ALP)活性含量显著下降，一氧化氮(NO)含量显著增加，骨强度、骨密度、骨矿盐含量(BMC)和骨胶原含量减少。结论 去负荷导致骨显微结构退化，骨局部因子含量改变，骨强度和骨量减少。     

男性骨质疏松患者股骨头松质骨微结构区域差异的研究

目的 探讨中国男性骨质疏松股骨颈骨折患者股骨头松质骨微结构的区域差异,明确微结构差异对股骨颈骨折的影响.方法 18例中国男性股骨颈骨折患者股骨头标本,根据脆性骨折分为骨质疏松骨折(11例)和外伤骨折(7例)2组.定位标记后取6 mm×6 mm×7mm的松质骨骨块9块,其中1块为主应力区标本,其他8块为非主应力区标本.行显微CT扫描,测量各骨块三维骨微结构参数.用t检验分析两组主应力区、非主应力区和所有标本平均值松质骨的微结构参数.结果 骨质疏松骨折组,非主应力区与主应力区相比,体积骨密度[非主应力区为(182.15 ±66.00)mg/mm3,主应力区为(223.97±70.92)mg/mm3,t=3.041]、组织骨密度[非主应力区为(538.76±64.72)mg/mm3,主应力区为(580.01±63.86)mg/mm3,t=3.160]、骨体积分数[非主应力区为(0.22±0.06)%,主应力区为(0.26±0.07)%,t=2.821]、骨小梁厚度[非主应力区为(161.07±42.75)μm,主应力区为(205.47±74.44)μm,t=3.233]显著下降,骨表面体积比[非主应力区为(13.75 ±2.55)mm-1,主应力区为(12.28±2.70)mm-1,t=-2.777]显著增加,差异均有统计学意义(P值均<0.05).在非主应力区,骨质疏松骨折组与外伤骨折组比较,体积骨密度[外伤骨折组为(248.05±105.48)mg/mm3,t=-3.598]、组织骨密度[外伤骨折组为(570.54 ±100.32)mg/mm3,t=-2.108]、骨体积分数[外伤骨折组为(0.28±0.12)%,t=-3.466]、骨小梁厚度[外伤骨折组为(200.31±96.63)μm,t=-2.866]、骨小梁数量[骨质疏松骨折组为(1.46±0.23)个/mm3,外伤骨折组为(1.57±0.29)个/mm3,t=-2.396]显著下降,骨小梁间隔[骨质疏松骨折组为(780.82±144.85)μm,外伤骨折组为(653.09±119.64)μm,t=5.470]、各向异性度(骨质疏松骨折组为1.57±0.20,外伤骨折组为1.47±0.18,t=2.930)显著增加,差异有统计学意义(P值均<0.05).所有18个标本主应力区骨小梁厚度[(199.37±68.22)μm]与非主应力区[(176.33±71.21)μm]比较显著增加,差异有统计学意义(t=2.060,P<0.05).结论 骨质疏松患者股骨头松质骨骨量的丢失和微结构的改变存在区域差异,非主应力区的退变更加明显.股骨头部位骨小梁厚度的改变可能是与股骨颈骨折关系最密切的微结构指标.     

椎体成形术的实验研究

目的　通过对骨质疏松的山羊椎体成形探讨椎体成形术的安全性和临床应用依据。材料与方法　将 5只复制成功的骨质疏松的山羊每只取 3个椎体 (L1～L5)共 15个椎体作为手术组 ,2个椎体 (L1～L5)共 10个椎体作对照组。手术解剖出椎弓根直视下椎体穿刺 ,注入聚甲基丙烯酸甲酯 (PMMA ,骨水泥 )。测量椎体中心、椎体前缘和椎体后缘的温度变化。CT检查椎体骨水泥充填情况。 3天后处死动物每只取 1个注射椎体共 5个椎体行病理检查。将另 10个注射椎体和 10个未手术对照组椎体游离成单个椎体 ,去掉椎间盘和椎体附件 ,双盲法测量其纵向最大负载、极限强度、弹性模量。结果　注射后椎体的最大负载、极限强度、弹性模量比对照组明显提高 (P <0 .0 5 )。注射骨水泥后椎体内中心温度为 5 1.12℃ ,椎体前缘 37.31℃ ,后缘 37.6 1℃。大体病理和显微病理显示骨水泥弥散在椎体内骨小梁间呈不均匀分布 ,同CT检查结果一致。结论　掌握适宜的粉液比例和注射时机是椎体成形术的关键因素 ,椎体内注入骨水泥可显著增强其纵向最大负载、极限强度、弹性模量     

腰椎侧凸患者椎体骨小梁结构稀少与骨质疏松的相关性

目的观察成人腰椎侧凸患者椎体骨小梁的改变及其与骨质疏松的相关性。资料与方法收集经腰椎CT检查确诊的腰椎侧凸患者(病例组)及无腰椎侧凸的腰腿痛患者(对照组)各100例,分别测量两组受试者椎体CT值及椎体骨小梁容积百分比(BV/TV);同时重建骨小梁的三维图像,观察骨小梁的结构改变。结果病例组椎体CT值及BV/TV值均较对照组明显降低(P<0.05)。容积再现三维图像显示,病例组患者骨小梁连续性中断,数目减少;对照组患者骨小梁相对致密。所有受试者BV/TV值与年龄呈负相关(r=―0.513,P<0.01)。结论随着年龄增加,BV/TV值降低,骨松质发生改变,腰椎侧凸发生率提高。骨小梁结构稀疏、数目减少及骨松质发生改变是成人发生腰椎侧凸的主要因素。     

Investigation of MR decay rates in microphantom models of trabecular bone

MR measurements of transverse relaxation time, T2*, in trabecular bone may provide both structural and density-related information for assessment of bone mineral status in osteoporosis. Using submillimeter scale glass phantoms as simplified models of trabecular bone, we have made a quantitative investigation of the dependence of T2* decay on modeled trabecular microstructure and MR image resolution. The experimental MR data are in excellent agreement with predictions from a computer simulation. Decreasing the modeled trabecular bone volume fraction, ζ, decreases the decay rate, as expected. However, if trabecular width and spacing are both increased without changing ζ, the decay rate is unchanged. The measured decay curves closely follow the predicted dependence on trabecular orientation. The decay rates are independent of image resolution, provided that the pixel dimensions are larger than the intertrabecular spacing. For smaller pixel sizes, the decay rate decreases with decreasing pixel size.     

Autocalibrating parallel imaging of in vivo trabecular bone microarchitecture at 3 Tesla.

In this work the generalized autocalibrating partially parallel acquisition (GRAPPA) technique was implemented with modified reconstruction and applied to in vivo high-resolution (HR) magnetic resonance imaging (MRI) of the trabecular bone microarchitecture at 3 Tesla (T) with a multiple-acquisition balanced steady-state free precession (b-SSFP) sequence. Trabecular bone is made up of a network of microstructures (80-140 microm), and its structural deterioration is associated with the skeletal metabolic disorder osteoporosis. HR-MRI is a promising noninvasive tool for assessing the trabecular microarchitecture in vivo, but it involves long acquisition times. Using partially parallel imaging (PPI) to accelerate the acquisition may help mitigate this shortcoming and allow more flexibility in protocol design. In this study the effects of GRAPPA-based reconstruction on image characteristics and the measurement of trabecular bone structural parameters were evaluated. Initial studies showed that image quality and depiction of microstructure were preserved in the GRAPPA-based reconstruction, indicating the feasibility of PPI in HR-MRI of trabecular bone. The results also demonstrated the potential of PPI for increasing the signal-to-noise ratio (SNR) efficiency of multiple-acquisition b-SSFP imaging protocols.     

精脒对老龄小鼠股骨微结构的影响

目的 探讨精脒(Spermidine)对老龄小鼠股骨微结构的影响.方法 选取20只21月龄C57老龄小鼠随机分为对照组(Vehicle,n=10)和实验组(Spermidine,n=10),Spermidine组在饮水中按3 mmol/L的浓度加入Spermidine,干预时间为12周.每周测量各组小鼠的体重;实验结束...     

New evaluation for osteoporosis using calcaneal computed radiographs

Quantitative analysis of bone mass is a method mainly used for the diagnosis of osteoporosis. However, there are cases of osteoporosis that cannot be diagnosed by this method alone. This study was performed to develop a new quantitative method for the evaluation of osteoporosis using texture analysis and geometric feature analysis of trabecular bone on lateral calcaneal computed radiographs. Thirty-seven cases including 11 normal and 26 abnormal lateral calcaneal radiographs were examined. The patients' ages ranged from 24 to 89 years (average age, 58.3 years). The root mean square (RMS) variation and first moment of power spectrum of trabecular bone patterns were determined as quantitative measures for texture analysis. In addition, the total area and total length of trabecular bone were obtained from geometric feature analysis. The RMS variations in pixel values, total area, and total length of trabecular bone were decreased as bone atrophy progressed. These three quantitative measures corresponded well to radiologists' subjective evaluations of bone atrophy. Moreover, our results indicated that these three quantitative measures had strong correlations with bone mineral density of the femoral neck. Therefore, we consider the computerized method with texture analysis and geometric feature analysis of lateral calcaneal radiographs to be very useful for radiologists in evaluating osteoporosis.     

Three-dimensional microstructural analysis of human lumbar vertebrae using microcomputed tomography in bone metastasis from prostate cancer

Prostate cancer frequently metastasizes to bone, inducing osteosclerotic lesions. However, the morphological details of bone metastasis of prostate cancer have not been clarified. The trabecular bone structure of bone metastasis from prostate cancer was investigated in three dimensions using microcomputed tomography (micro-CT). A total of 17 cubes of the lumbar spine of a 77-year-old man with prostate cancer were excised post mortem: four of them from non-metastatic and the rest from metastatic sites. The samples were measured using micro-CT with a resolution of 23.2 microns and the standard structural indices and degree of anisotropy were computed. After micro-CT measurement, the samples were tested in a destructive manner for the assessment of mechanical properties. Samples from the metastatic sites showed significantly higher values than those from non-metastatic sites for bone volume (BV), bone surface (BS), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N) (p < 0.005). Bone surface density (BS/BV) and trabecular separation (Tb.Sp) were significantly higher in the samples from non-metastatic sites (p < 0.001). Samples from metastatic sites showed a more isotropic arrangement of trabecular bone than those from non-metastatic sites. Three-dimensionally reconstructed images depicted several different patterns of sclerotic bone metastasis, and osteolytic appearance was observed in all of them. Structural parameters such as BV/TV were well correlated with the mechanical properties (r = 0.899). The present study clarified the trabecular microstructure of bone metastasis from prostate cancer and suggests that both osteolysis and osteogenesis progress while interacting with each other in all phases of bone metastasis.     

Structural and functional assessment of trabecular and cortical bone by micro magnetic resonance imaging

Osteoporosis is a multifactorial disorder of bone mineral homeostasis affecting the elderly. It is a major public health issue with significant socioeconomic consequences. Recent findings suggest that bone loss-the key manifestation of the disease-is accompanied by architectural deterioration, both affecting the bone's mechanical competence and susceptibility to fracture. This article reviews the potential of quantitative micro MRI (mu-MRI), including a discussion of the technical requirements for image acquisition, processing, and analysis for assessing the architectural implications of osteoporosis and as a means to monitor the response to treatment. With current technology, the resolution achievable in clinically acceptable scan times and necessary signal-to-noise ratio (SNR) is comparable to trabecular thickness. This limited spatial resolution regime demands processing and analysis algorithms designed to operate under such limiting conditions. It is shown that three different classes of structural parameters can be distinguished, characterizing scale, topology, and orientation. There is considerable evidence that osteoporotic bone loss affects all three classes but that topological changes, resulting from conversion of trabecular plates to rods, with the latter's eventual disconnection, are particularly prominent. Clinical applications discussed can be divided into those dealing with assessment of osteoporotic fracture risk as opposed to the study of the effect of disease progression and regression in response to treatment. Current data suggest that noninvasive assessment of cortical and trabecular bone (TB) architecture by mu-MRI may provide new surrogate endpoints to assess the efficacy of intervention in osteoporosis treatment and prevention.     

模拟失重大鼠骨折风险及性别差异性研究

目的探讨模拟失重下雌、雄性大鼠影像学参数预测骨折风险相关性及性别差异的原因。方法 3月龄雌、雄性SD大鼠40只,按性别及是否失重随机分为4组,4周后,双能X线检测L4椎体、股骨BMD,Micro-CT分析骨小梁结构,生物力学测试力学强度。结果失重4周后,雌性组子宫重量降低47.3%,雄性组精囊重量降低39.5%。失重试验组BMD显著下降,骨体积分数(BV/TV)、骨小梁厚度(Tb.Th)、骨小梁数目(Tb.N)显著降低(P0.05),骨小梁间隙(Tb.Sp)显著增加;悬吊组椎体的最大压缩载荷(N)、压缩压力(MPa)、抗弯曲载荷(N)较对照组显著下降。BMD、BV/TV、Tb.Th、Tb.N、Tb.Sp与最大力学强度Fmax相关性系数r,雄性组为0.985、0.995、0.948、0.957、-0.990,雌性组为0.908、0.899、0.873、0.852、-0.76。结论失重4周后,不同性别大鼠BMD明显降低,激素水平的影响可能是模拟失重雌性大鼠骨丢失更严重原因之一。骨密度与失重后生物力学的相关性可综合有效地预测失重后的骨折风险。     

An update on the assessment of osteoporosis using radiologic techniques

In this article, the currently available radiologic techniques for assessing osteoporosis are reviewed. Density measurements of the skeleton using dual X-ray absorptiometry (DXA) are clinically indicated for the assessment of osteoporosis and for the evaluation of therapies. DXA is the most widely used technique for identifying patients with osteoporosis. Quantitative computed tomography (QCT) is the only method, which provides a volumetric density. Unlike DXA, QCT allows for selective trabecular measurement and is less sensitive to degenerative diseases of the spine. The analysis of bone structure in conjunction with bone density is an exciting new field in the assessment of osteoporosis. High-resolution multi-slice CT and micro-CT are useful tools for the assessment of bone microarchitecture. A growing literature indicates that quantitative ultrasound (QUS) techniques are capable of assessing fracture risk. Although the ease of use and the absence of ionizing radiation make QUS attractive, the specific role of QUS techniques in clinical practice needs further determination. Considerable progress has been made in the development of MR techniques for assessing osteoporosis during the last few years. In addition to relaxometry techniques, high-resolution MR imaging, diffusion MR imaging and in-vivo MR spectroscopy may be used to quantify trabecular bone architecture and mineral composition.     

Differential effects of menopause and metabolic disease on trabecular and cortical bone assessed by peripheral quantitative computed tomography (pQCT)

The usefulness of peripheral quantitative computed tomography (pQCT) was investigated in the diagnosis of metabolic bone diseases, including osteoporosis, and especially in the different diagnostic values in trabecular and cortical components. The subjects were 460 Japanese women aged 20-86 years, including 318 healthy volunteers, 58 osteoporotics with fracture and 84 patients with diseases including amenorrhoea, steroid-induced osteoporosis, renal osteodystrophy (ROD) and primary hyperparathyroidism. Bone mineral density (BMD) was measured for more than 4 years in 74 of the healthy volunteers. BMD was measured by spinal QCT, dual X-ray absorptiometry (DXA) of the spine, radius, and heel, and pQCT of the radius and tibia. High resolution images were obtained for geometry of the radius. Radial pQCT showed a higher correlation with radial DXA than with spinal QCT, and spinal QCT showed a higher correlation with spinal DXA than with radial pQCT. The annual bone loss rates at predominantly trabecular bone sites were accelerated in both the axial and appendicular skeleton. In the fracture study, radial pQCT showed a higher odds ratio (OR = 4.4) than radial DXA, and cortical area ratio seemed to be a good predictor of fracture risk (OR = 5.2). Amenorrhoea and steroid-induced osteoporosis predominantly affected trabecular bone, ROD predominantly affected cortical bone and hyperparathyroidism affected both components, especially the cortical component. pQCT is useful for assessing both trabecular and cortical bone, to provide information on individual bone changes in metabolic bone disease and to estimate the risk of fracture.     

Appearance of trabecular bone in the femoral neck (Singh index). Relation to vertebral bone mass post mortem.

In 89 consecutive cases trabecular bone mass of the second or third lumbar vertabra was subjectively estimated in post mortem specimens, using frontal section 1 cm in thickness. The trabecular appearance of the femoral neck (Singh index) at radiography and the thickness of the femoral cortical bone were also determined. Agreement between vertebral bone mass and either of the two radiologic indices was present in only two thirds of the cases, and most often these indices underestimated the presence of vertebral osteoporosis. The results indicate that neither of these radiologic indices can be used for clinical guidance of the diagnosis of vertebral osteoporosis in the individual case.