腰椎定量CT骨密度测量椎体内差异研究

目的研究受检者椎体内不同感兴趣区(ROI)腰椎定量CT(QCT)骨密度测量结果的差异,以提高其测量的准确性和可重复性。资料与方法对206例受检者进行腰椎检查(99例经GE64排螺旋CT扫描,107例经东芝16排螺旋CT扫描),获取扫描数据,通过Mindways QCT PRO工作站进行分析处理,使用软件的3D测量模式进行测量,ROI分别放在每个椎体的上、中、下1/3部位,分别测量L1～L3椎体上、中、下3个部位松质骨骨密度(BMD)。结果 L1～L3椎体上、中、下平均BMD分别为(116.75±47.73)mg/cm3、(126.37±47.63)mg/cm3和(123.77±52.67)mg/cm3,椎体内BMD差异有统计学意义(P<0.01),椎体内各部分骨密度相差<8%。结论腰椎椎体内BMD存在区域性差异,QCT BMD测量时应选择相同的感兴趣区以减少误差,但在实际临床应用中影响较小。     

胸椎定量CT和腰椎双能X线吸收检测仪对绝经后女性骨质疏松症的诊断差异

【摘要】目的：研究胸椎定量CT(QCT)和双能X线吸收检测仪(DXA)对绝经后女性骨质疏松症的诊断差异,以及胸椎QCT在绝经后女性骨质疏松筛查中的价值。方法：选取 2020年8月～2021年8月同时行胸部CT与腰椎及髋关节DXA检测的绝经后女性192例,获取胸7-9椎体QCT及腰1-4椎体和左髋关节DXA的BMD和T值,结合文献以胸7-9椎体QCT的平均BMD 90mg/cm3和136mg/cm3作为判定骨质疏松和骨量减少的阈值,比较胸椎QCT和双能DXA对绝经后女性骨质疏松症的检出率的差异并评估BMI对腰椎DXA的BMD及T值和胸椎QCT的BMD的影响。结果：192例绝经期女性的平均年龄为64.79岁,胸椎QCT对绝经后女性骨量减少以及骨质疏松症的检出率同腰椎DXA对其检出率有统计学差异（P＜0.05）,QCT和DXA完全符合者100例（52.08%）,不符合者92例（47.92%）,其中80例（41.67%）在DXA被低估;不同BMI对腰椎DXA的BMD及T值有统计学差异（P＜0.05）,而对胸椎QCT的BMD无统计学差异（P＞0.05）。结论：胸椎QCT对绝经后女性骨质疏松的检出率优于双能DXA,胸部 CT 检查联合胸椎QCT获得胸椎BMD可指导绝经后女性进行骨质疏松的筛查,在绝经后女性人群中对骨质疏松症的诊断具有重要价值。     

比较双能X线吸收测量仪与显微CT显示不同时期去卵巢大鼠胫骨骨量和微结构的特点

目的 应用和比较双能X线吸收测量仪(DXA)与显微CT(μCT)观察不同时期去卵巢(OVX)大鼠胫骨骨量及骨微结构的改变特点.方法 40只7个月龄SD大鼠以简单随机抽样方法分为OVX组和假手术(SHAM)组,每组20只,于手术后3周及15周分别处死10只.处死后剥离左侧胫骨行DXA扫描,从胫骨近端开始将胫骨按其长度等分为7个感兴趣区(ROI1～7),计算获得各区域及总体骨密度值.然后将胫骨以4%多聚甲醛固定24 h,10%蔗糖溶液洗涤后行μCT扫描,选取距生长板远端2.5 mm、层厚0.4 mm骨组织为皮质骨感兴趣区域,选取距生长板远端0.7 mm、层厚1.2 mm骨组织为松质骨感兴趣区域行三维重组.获取二维最大密度投射图像及三维结构图像,并对感兴趣区的皮质骨和松质骨进行定量分析.所得结果以独立样本t检验进行比较.结果 3周时,OVX组大鼠胫骨ROI1区骨密度为(0.2346±0.0280)g/cm2,显著低于SHAM组(0.2660±0.0199)g/cm2,(P＜0.05);15周时,OVX组大鼠胫骨ROI1区及ROI2区骨密度分别为(0.2527±0.0161)及(0.1862±0.0052)g/cm2,较SHAM组(0.2793±0.0229)及(0.1986±0.0102)g/cm2有明显下降(P值均＜0.01).3周时,OVX组大鼠骨皮质骨面积、骨髓腔面积、截面总面积、截面惯性矩分别为(0.4306±0.1308)、(10.31±1.98)、(10.74±2.05)mm2和(4.101±0.726)mm4,均明显高于SHAM组(0.3138±0.0621)、(8.44±1.25)、(8.75±1.26)mm2和(3.485±0.373)mm4(P值均＜0.05).至15周时,除皮质骨平均厚度OVX组大鼠为(0.0235±0.0024)mm,低于SHAM组(0.0285±0.0052)mm外(P＜0.05),其余各参数差异均无统计学意义.15周OVX组大鼠左侧胫骨骨丢失敏感区域内皮质骨平均厚度和皮质骨面积为(0.0235±0.0024)mm及(0.2528±0.0367)mm2,较3周OVX组大鼠(0.0377±0.0098)mm及(0.4306±0.1308)mm2有明显下降(P值均＜0.05).SHAM组,15周大鼠骨内径周长、骨外径周长和截面惯性矩分别为(13.38±0.54)、(13.59±0.56)mm和(4.096±0.364)mm4,与3周大鼠(12.41±0.74)、(12.63±0.75)mm和(3.485±0.373)mm4相比差异有统计学意义(P值均＜0.05).3周时,OVX组大鼠体积骨密度、组织骨密度、骨体积分数和骨小梁数量分别为(288.2±48.2)、(604.5±45.3)mg/mm3和(25.1±5.1)%、(6.04±2.94)mm-1,显著低于SHAM组(408.4±51.6)、(686.7±40.0)mg/mm3和(33.6±4.1)%、(9.85±2.83)mm-1(P值均＜0.05),结构模型指数、骨小梁间隔则分别为3.09±0.27及(0.186±0.129)mm,明显高于SHAM组2.63±0.21及(0.078±0.038)mm(P值分别＜0.01和＜0.05).至15周时,OVX组体积骨密度、骨体积分数、骨小梁数量、结构模型指数和骨小梁间隔分别为(271.2±50.9)mg/mm3、(21.6±5.2)%、(3.21±1.92)mm-1、3.11±0.36、(0.370±0.215)mm与SHAM组(389.8±77.0)mg/mm3、(30.9±6.0)%、(7.44±3.53)mm-1、2.58±0.36、(0.141±0.104)mm的差异均有统计学意义(P值均＜0.01),但组织骨密度差别消失.15周OVX组大鼠组织骨密度、骨小梁厚度、骨小梁数量、骨小梁间隔分别为(691.0±36.7)mg/mm3、(0.040±0.009)mm、(3.21±1.92)mm-1、(0.370±0.215)mm较3周OVX大鼠(604.5±45.3)mg/mm3、(0.030±0.002)mm、(6.04±2.94)mm-1、(0.186±0.129)mm差异有统计学意义(P值均＜0.05).结论 DXA是一种应用广泛的骨密度测量方法,但可能无法及时准确地反映出大鼠去卵巢后骨量的变化.μCT是研究骨密度和骨微结构细微改变的较合适的方法.     

绝经后妇女腰椎骨密度容积性定量CT测量研究

目的 应用容积性定量CT(vQCT)技术和双能X线吸收测量(DXA)仪测量绝经后妇女腰椎容积性骨密度(BMD),评价2种检查方法区分骨质疏松伴椎体骨折与骨质疏松不伴骨折的差异.方法 选取绝经后妇女118名[平均年龄(62.1±7.0)岁],按照所行胸腰椎X线平片检查结果及腰椎DXA测量的参数[前后位BMD(AP-SPINE)]值分组,>均值-1个标准差(x-1s)为正常组、x-1s～x-2s为骨量减少组、0.05).在骨质疏松组和骨质疏松伴骨折组AP-SPINE仅与3D-CORT间有相关性(R2=0.189,P<0.01);App60 BV/TV%、App80 BV/TV%、App100 BV/TV%、App120 BV/TV%与3D-TRAB或2D-TRAB之有相关性(3D法:R2值分别为0.955、0.951、0.941、0.912;2D法:R2值分别为0.912、0.910、0.878、0.821;P值均<0.01).容积性BMD的测量精确度为0.70%～2.25%.结论 vQCT技术可区分骨质疏松及伴骨质疏松性骨折绝经后妇女骨量,能力高于DXA,其中整体骨BMD诊断严重骨质疏松的效果最好;App BV/TV%可反映骨质疏松者骨小梁丢失程度,预测骨折风险.     

骨质疏松老年妇女股骨近端16层螺旋CT的定量研究

目的:通过16层螺旋CT中vQCT技术对骨质疏松性椎体骨折及无骨折老年妇女股骨近端进行多个容积性BMD指标的测量,比较两组妇女股骨近端小梁骨、皮质骨和整体骨容积性BMD的差异,评价骨质疏松性椎体骨折对股骨近端骨密度的影响程度。方法:将26例骨质疏松性椎体骨折病人归为第一组,年龄与第一组匹配的无脊椎骨折的30例骨质疏松老年妇女归为第二组。应用GE公司LightSpeed16型螺旋CT对56例病人股骨近端行容积扫描,行薄层重建图像,层厚1·25mm,在3D-VR影像中沿左股骨颈长轴方向确定数个与之相垂直的平面作为固定的解剖学标记,选取左侧股骨近端整体骨、股骨颈及粗隆间测量兴趣体积(VOI),经SunADW4·0计算机工作站直方图(histogram)功能测量左侧股骨颈3D小梁骨BMD(N-TRAB)、3D整体骨BMD(N-INTGL),左侧粗隆间3D小梁骨BMD(T-TRAB)、3D整体骨BMD(T-INTGL),左侧股骨近端3D小梁骨BMD(FEM-TRAB)、3D皮质骨BMD(FEM-CORT)和3D整体骨BMD(FEM-INTGL)值。所有病人双能X线吸收仪(GE-Lunar公司DPX型)测量指标为左侧股骨颈(NECK)及粗隆间BMD(TROCH)。比较两组老年妇女间9项BMD指标差异采用协方差分析。结果:两组老年妇女间股骨近端容积性BMD数值除FEM-CORT一项指标外其差异存在统计学意义,在调节年龄和体型因素后仍然在差异,第一组老年妇女比第二组容积性BMD值下降程度为14%~18%,且vQCT技术中股骨近端容积性BMD的测量精度较高;两组间DXA指标中BMD值的差异在调节年龄和体型因素后无统计学意义:在TTRAB指标中第一组老年妇女比第二组的BMD值下降幅度达17·7%,高于N-TRAB中BMD值的下降度14·3%。结论:首次应用16层螺旋CT进行股骨近端vQCT测量,证实此项技术比DXA更全面地反应骨质疏松性椎体骨折比无骨折老年妇女股骨近端骨密度的下降状况,且不受体型大小和骨形态变化因素的影响。     

定量CT与双能X线吸收测定仪测量腰椎各椎体间骨密度差异性研究

目的探讨L2～L4椎体的骨密度变化趋势,并比较定量CT(QCT)与双能X线骨密度仪(DXA)测量结果的差异。资料与方法从多中心合作数据库中选择11443名志愿者数据进行L2～L4椎体骨密度(BMD)分析,其中11081名志愿者选用DXA检测椎体BMD值,男性2158名,女性8923名;362名志愿者选用QCT检测椎体中间松质骨BMD值,男性170名,女性192名,比较二者测量各腰椎BMD的差异。结果 DXA测量椎体间BMD值差异有统计学意义(男性:F=74.450,P<0.05;女性:F=605.388,P<0.05),从L2～L4呈增加趋势;QCT测量椎体间BMD值差异无统计学意义(男性:F=1.291,P>0.05;女性:F=1.653,P>0.05)。结论 QCT是真正意义上的体积骨密度测量技术,能更准确地测量骨密度。     

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.     

双能X线骨密度仪(DXA)与定量CT(QCT)测量骨密度的比较研究

目的比较定量CT（QCT）和双能X线骨密度仪（DXA）所得测定值与灰重密度的相关性以及两种方法所得体积骨密度的偏离度,探讨QCT测量BMD的临床应用价值。材料与方法取15节猪腰椎椎体,去除周围软组织及附件,分别用QCT及DXA两种方法测量骨密度,再将去附件椎体灰化,将各自测得的总骨矿含量及骨密度与灰化后得到的椎体的灰重以及灰重密度比较。计算出DXA测量的体积骨密度,QCT测得的皮质骨密度、松质骨密度以及DXA测量得到的体积骨密度分别相对灰重密度的偏离度。结果QCT与DXA测量结果与灰重、灰重密度均有显著相关性（P〈0.005）,其中以DXA测得总骨矿含量与灰重的相关性最显著（r=0.9995）。且相对灰重密度,QCT测得松质骨密度的偏离度（平均值0.1489）低于DXA测量得到的体积骨密度的偏离度（平均值0.2708）（P〈0.05）。结论QCT和DXA都是判断骨矿含量和诊断骨质疏松症较好的方法;QCT测量松质骨密度更接近于作为标准值的灰重密度;QCT测量松质骨密度比DXA测量骨密度能更好、更准确地反映骨质疏松的骨代谢变化。     

基于磁共振水-脂分离技术的绝经后OP髋部的定量研究

目的利用磁共振水-脂分离成像技术计算骨髓脂肪分数(fat fraction, FF)、通过髋部脂肪含量评估,提示是否骨质疏松(osteoporosis, OP)。方法收集绝经后女性78例,通过双能X线吸收测量法(dual-energy X-ray absorptiometry, DXA)测定骨密度值(bone mineral density, BMD)分为骨量正常组和低骨量组,利用磁共振水-脂分离技术测算FF,比较分析两组的全髋、股骨颈、股骨粗隆、ward三角BMD与FF值。结果通过DXA测量两组全髋、股骨颈、股骨粗隆、ward三角的BMD值,经方差分析,差异具有统计学意义(P0.05),采用MRI水-脂分离技术测量全髋、股骨颈、股骨粗隆、ward三角的FF值,经方差分析,差异具有统计学意义(P0.05),结果提示髋部MRI水-脂分离技术与DXA测量在骨量评估方面有较好的相关性。结论 MRI水-脂分离技术在一定程度上可以作为DXA的辅助,对绝经后OP髋部的评估有较好的临床应用价值。     

大鼠去势后骨量及骨松质骨髓脂肪变化的DXA、QCT和CSI表现及其相关性研究

目的:应用双能X线检测(dual energy X-ray absorptiometry,DXA)、多层螺旋CT骨矿容积含量测定(quantitative computed tomography,QCT)和磁共振化学位移成像(chemical shift imaging,CSI)检查大鼠全身骨及骨松质,结合骨髓脂肪含量病理结果,探讨在生理状态下利用不同影像学方法检测骨松质骨量和骨髓脂水含量变化,为骨松质变化的早期诊断提供影像学依据.方法:SD大鼠(12周龄)雌雄各30只,完全随机化方法进行:假手术(雌雄各10只);去势手术(雌雄各20只).在手术后第12周和第16周各取半数进行影像学检查,得到DXA、QCT和化学位移率(chemical shift ratio,CSR),结合光镜下骨松质HE染色切片得到的骨髓脂肪含量(fat fraction,%FF),进行对比分析.结果:在50只具有有效研究数据的大鼠中,骨髓高脂肪组大鼠的DXA(0.310±0.014mg/cm2)、QCT(427.88±39.25mg/cm3)和CSR(0.673±0.167)均比骨髓低脂肪组的(DXA为0.320±0.014mg/cm2、QCT为503.86±79.02mg/cm3、CSR为0.828±0.245)要低(P<0.05).经Pearson检验,DXA与QCT间相关性(P=0.021)及CSR与QCT间相关性(P=0.016)都有统计学意义;DXA与CSR间的相关性(P=0.254)没有统计学意义.结论:骨松质骨髓脂肪含量增加,DXA和QCT就减少,相应的骨髓化学位移率降低.化学位移成像可以无创伤、无辐射的检测骨髓脂肪含量的变化,间接推测骨松质骨矿含量的变化.     

Influence of anthropometric parameters and bone size on bone mineral density using volumetric quantitative computed tomography and dual X-ray absorptiometry at the hip

PURPOSE: To evaluate the influence of anthropometric parameters (age, height, and weight) and bone size on bone mineral density (BMD) using volumetric quantitative computed tomography (QCT) and dual X-ray absorptiometry (DXA) in a group of elderly women. MATERIAL AND METHODS: BMD values were obtained with DXA and QCT at the spine and hip in a cohort of 84 elderly women (mean age 73 +/- 6 years). QCT measures included trabecular, integral, and cortical BMD assessed at the hip and spine as well as cross-sectional areas of the mid-vertebrae and proximal femora. Spinal integral and femoral neck BMD measures were well matched to the regions of bone quantified on anteroposterior (AP) spine DXA and the femoral neck region of hip DXA. RESULTS: When QCT parameters were linearly regressed against body height and weight, only the relationships with weight were found to be statistically significant. Except for cortical BMD at the femoral neck, all BMD and geometric parameters measured from both DXA and QCT showed statistically significant associations with body weight (r2 = 0.4, 0.0001 < P < 0.02). The strongest associations with weight were found for DXA Neck (DXA_NECK) and DXA lumbar spine (DXA_LSP) (r2 = 0.4, P < 0.0001). CONCLUSION: The relationship of DXA BMD is stronger than QCT BMD with body weight and it encompasses the response of both bone size and density to increasing body mass.     

Effect of spinal degenerative changes on volumetric bone mineral density of the central skeleton as measured by quantitative computed tomography

Purpose: To evaluate the impact of degenerative changes due to osteoarthritis (OA) at the spine on volumetric bone mineral density (BMD) as measured by volumetric quantitative computed tomography (vQCT).

Material and Methods: Eighty-four elderly women (mean age 73±6 years), comprising 33 with vertebral fractures assessed by radiographs and 51 without vertebral fractures, were studied. Trabecular, cortical, and integral BMD were examined at the spine and hip using a helical CT scanner and were compared to dual X-ray absorptiometry (DXA) measurements at the same sites. OA changes visible on the radiographs were categorized into two grades according to severity. Differences in BMD measures obtained in the two groups of patients defined by OA grade using the described radiologic methods were compared using analysis of variance. Standardized difference (effect sizes) was also compared between radiologic methods.

Results: Spinal trabecular BMD did not differ significantly between OA grade 0 and OA grade 1. Spinal cortical and integral BMD measures showed statistically significant differences, as did the lumbar spine DXA BMD measurement (13%, P = 0.02). The QCT measurements at the hip were also higher in OA 1 subjects. Femoral trabecular BMD was 13-15% higher in OA grade 1 subjects than in OA grade 0 subjects. The cortical BMD measures in the CT_TOT_FEM and CT_TROCH ROI's were also higher in the OA 1 subjects. The integral QCT BMD measures in the hip showed difference between grades OA 1 and 0. The DXA measurements in the neck and trochanter ROI's showed smaller differences (9 and 11%, respectively). There were no statistically significant differences in bone size.

Conclusion: There is no evidence supporting that trabecular BMD measurements by QCT are influenced by OA. Instead, degenerative changes have an effect on both cortical and integral QCT, and on DXA at the lumbar spine and the hip. For subjects with established OA, assessment of BMD by volumetric QCT may be suggested.     

MR扩散加权成像评估椎体骨量状况的初步研究

目的 探讨椎体MR扩散加权成像(DWI)测量值与双能X线(DXA)、定量GT(QCT)所测骨密度的相关性.方法 152例女性志愿者分别进行以下检查:胸腰椎侧位(T4～L4)X线平片,并采用Genant半定量法对其进行评阅;腰椎(L2～L4)DXA和QCT骨密度测量;腰椎常规行MR矢状面T2 WI、T1 WI和横断面T2 WI扫描;MR常规扫描结束后采用单次激发自旋回波平面回波扩散加权序列(SS-SE-EPI DWI)[扩散敏感因子(b)=500 s/mm2]进行L2～L4椎体横断面DWI扫描,并使用GE-Functool分析软件测量相应椎体表观扩散系数(ADC值).计量资料间的相关性采用Pearson相关分析.结果 随年龄增加,椎体ADC值呈逐步降低趋势.L2～L4椎体平均ADC值(0.241×10-3 mm2/s)与相应椎体平均骨密度DXA(I.038 s/cm2)、QCT(104.2 mg/cm3)具有相关性(r值分别为0.461、0.731,P值均＜0.01).结论 DWI可在常规2腰椎MRI基础上无创性评估椎体骨髓变化状况,进而来评估骨髓的变化对于骨量状况所带来的影响.     

Quantitative computed tomography

Quantitative computed tomography (QCT) was introduced in the mid 1970s. The technique is most commonly applied to 2D slices in the lumbar spine to measure trabecular bone mineral density (BMD; mg/cm³). Although not as widely utilized as dual-energy X-ray absortiometry (DXA) QCT has some advantages when studying the skeleton (separate measures of cortical and trabecular BMD; measurement of volumetric, as opposed to ‘areal’ DXA-BMDa, so not size dependent; geometric and structural parameters obtained which contribute to bone strength). A limitation is that the World Health Organisation (WHO) definition of osteoporosis in terms of bone densitometry (T score ?2.5 or below using DXA) is not applicable. QCT can be performed on conventional body CT scanners, or at peripheral sites (radius, tibia) using smaller, less expensive dedicated peripheral CT scanners (pQCT). Although the ionising radiation dose of spinal QCT is higher than for DXA, the dose compares favorably with those of other radiographic procedures (spinal radiographs) performed in patients suspected of having osteoporosis. The radiation dose from peripheral QCT scanners is negligible. Technical developments in CT (spiral multi-detector CT; improved spatial resolution) allow rapid acquisition of 3D volume images which enable QCT to be applied to the clinically important site of the proximal femur, more sophisticated analysis of cortical and trabecular bone, the imaging of trabecular structure and the application of finite element analysis (FEA). Such research studies contribute importantly to the understanding of bone growth and development, the effect of disease and treatment on the skeleton and the biomechanics of bone strength and fracture.     

Bone mineral density reference values in the normal female and male population of Izmir,Turkey

In this study we aimed to establish the dual-energy X-ray absorptiometry (DXA) bone mineral density (BMD) reference values of healthy Turkish women and men residing in Izmir, western Turkey. We examined 347 women and 119 men (age range 20-80 years) who did not have any known risk factor that might affect bone mass. The BMD measurements were performed by Hologic QDR 4500 W Elite DXA instrument from the lumbar spine (L1-L4) and non-dominant hip. In women the mean BMD (g/cm(2))+/-standard deviation (SD) of the normal reference group between 20 and 39 years of age was 0.963+/-0.121 g/cm(2) in the lumbar spine and 0.891+/-0.119 g/cm(2) in total femoral region. The percentages of annual and total BMD losses in women between 30 and 80 years of age were 0.74 and 29% at spinal level and 0.65 and 26% in femoral region, respectively. The average BMD of the normal men's group between 20 and 39 years of age was 0.996+/-0.111 g/cm(2) in the lumbar spine and 1.025+/-0.110 g/cm(2) in femoral region. The percentages of annual and total BMD losses were 0.33 and 13% at spinal level and 0.50 and 20% in femoral region, respectively. In conclusion, like the values reported from mid-Anatolian region of Turkey, the BMD values of Turkish women and men residing in Izmir, western Anatolia, are also lower than in most European countries with regard to US and preinstalled Hologic values.     

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.     

Quantitative computed tomography

Quantitative computed tomography (QCT) is an established technique for measuring bone mineral density (BMD) in the axial spine and peripheral skeleton (forearm, tibia). QCT can determine in three dimensions the true volumetric density (mg/cm 3) of trabecular or cortical bone at any skeletal site. However, because of the high responsiveness of spinal trabecular bone and its importance for vertebral strength, QCT has been principally employed to determine trabecular BMD in the vertebral body. QCT has been used for assessment of vertebral fracture risk, measurement of age-related bone loss, and follow-up of osteoporosis and other metabolic bone diseases. This article reviews the current capabilities of QCT at different skeletal sites and the recent technical developments, including volumetric acquisition.     

Assessment of bone mineral density in the jaws and its relationship to radiomorphometric indices

Objectives

The aim of this study was to evaluate maxillary, mandibular and femoral neck bone mineral density using dual energy X-ray absorptiometry (DXA) and to determine any correlation between the bone mineral density of the jaws and panoramic radiomorphometric indices.

Methods

49 edentulous patients (18 males and 31 females) aged between 41 and 78 years (mean age 60.2 ± 11.04) were examined by panoramic radiography. Bone mineral density (BMD) of the jaws and femoral neck was measured with a DXA; bone mineral density was calculated at the anterior, premolar and molar regions of the maxilla and mandible.

Results

The mean maxillary molar BMD (0.45 g cm⁻²) was significantly greater than the maxillary anterior and premolar BMD (0.31 g cm⁻², P < 0.05). Furthermore, the mean mandibular anterior and premolar BMD (1.39 g cm⁻² and 1.28 g cm⁻², respectively) was significantly greater than the mean mandibular molar BMD (1.09 g cm⁻², P < 0.01). Although BMD in the maxillary anterior and premolar regions were correlated, BMD in all the mandibular regions were highly correlated. Maxillary and mandibular BMD were not correlated with femoral BMD. In addition, mandibular cortical index (MCI) classification, mental index (MI) or panoramic mandibular index (PMI) values were not significantly correlated with the maxillary and mandibular BMDs (P > 0.05).

Conclusions

The BMD in this study was highest in the mandibular anterior region and lowest in the maxillary anterior and premolar regions. The BMD of the jaws was not correlated with either femoral BMD or panoramic radiomorphometric indices.