Relationship Among MRTA, DXA, and QUS Revisited

Inexpensive, commercially produced devices that directly measure bone strength in vivo are not currently available. Mechanical response tissue analysis (MRTA), a unique prototype device, is an in vivo vibrational test that measures transverse bending stiffness (a measure of whole bone strength expressed as the product of estimated Young's modulus of elasticity and cross-sectional moment of inertia, EI, Nm2) at ulna midshaft. We compared speed of sound (SOS; [m/s]) in ulna cortical bone using a commercially available axial transmission quantitative ultrasound (QUS) device with EI using MRTA. Dual-energy X-ray absorptiometry (DXA) was used to provide an estimate of ulna size (cm2), bone mineral content (BMC; [g/cm]) and areal bone mineral density (BMD; [g/cm2]). The objective of the study was to determine if ulna SOS--alone or in combination with BMD from DXA--was correlated with ulna EI, thus becoming a surrogate measure of transverse bending stiffness, and thus whole bone strength. Data were collected from 138 female volunteers (18-86 yr). EI and SOS were significantly correlated, r = +0.218, p = 0.01, but r2 was very low, 4.8%. SOS and total ulna BMD were combined to estimate elastic modulus, which correlated with EI, r = +0.377, p < 0.0001; however, the correlation was not significantly better than with SOS alone. We conclude that axial transmission QUS is not a strong surrogate in vivo technique for estimating transverse bending stiffness.     

绝经后中国女性跟骨定量超声和双能X线检查骨质疏松症的对比研究

目的观察绝经后中国女性跟骨定量超声和双能X线检查骨质疏松症的效果比较。方法评估234名绝经后未接受过治疗的40～80岁女性的腰椎、双侧股骨颈和全髋关节部位的骨密度(bone mineral density,BMD)的DXA参数和左右跟骨的QUS参数。计算BMD和QUS参数的相关系数。生成接收器操作特性曲线,并评估曲线下面积(area under curve,AUC)来定义QUS的截止值。结果跟骨QUS能够识别右侧髋关节(AUC,0. 887)和左股骨颈(AUC,0. 824)的T值为-2. 5或更低的绝经后妇女。为了筛选目的,定义了右侧(1. 455)和左侧(1. 480)跟骨的QUS T值的截止值。结论与DXA这种标准的诊断方法相比,可以推荐QUS作为预筛选工具来减少DXA筛查的数量。     

QCT和DXA对腰椎骨质疏松症检出率的Meta分析

目的 通过对定量CT（quantitative computed tomography,QCT）和双能X线吸收测量仪(dual-energy X-ray absorptiometry,DXA）腰椎骨质疏松症(osteoporosis ,OP)检出率研究数据进行Meta分析,了解QCT和DXA对腰椎OP的诊断价值。方法 检索 PubMed、Web of Science、Cochrane Library、万方、维普及中国知网中自建库以来至2022年1月1日的相关文献,提取目标数据。采用Stata 11.0软件进行数据分析,根据异质性检验结果选择固定效应模型或随机效应模型对数据进行汇总分析。结果 共纳入24篇研究,总样本量为4 008例,其中男性2 265例,女性1743例。24项研究间异质性显著,按随机效应模型分别汇总QCT和DXA对腰椎OP检出率为0.44(95 %CI：0.37~0.52)和0.17(95 %CI：0.14~0.21)。QCT对男、女性腰椎OP检出率分别为0.32(95 %CI：0.22~0.43)和0.45(95 %CI：0.33~0.58),DXA则分别为0.14(95 %CI：0.08~0.20)和0.24(95 %CI：0.17~0.30)。QCT在45~、60~岁和75岁及以上的人群中腰椎OP检出率分别为0.41(95 %CI：0.21~0.61)、0.43(95 %CI：0.33~0.54)和0.48(95 %CI：0.41~0.54),DXA则分别为0.30(95 %CI：0.12~0.49)、0.16(95 %CI：0.11~0.20)和0.15(95 %CI：0.10~0.21)。QCT和DXA对国内人群腰椎OP检出率分别为0.40(95 %CI：0.33~0.47)和0.15(95 %CI：0.12~0.19),对国外人群分别为0.68(95 %CI：0.43~0.93)和0.28(95 %CI：0.18~0.39)。QCT与DXA对腰椎OP检出率的差值(率差)定量合并结果为0.25(95 %CI：0.20~0.31),在男性为0.26(95 %CI：0.18~0.34),在女性为0.28(95 %CI：0.17~0.39),在45~、60~岁和75岁及以上人群中分别为0.10(95 %CI：0.06~0.14)、0.26(95 %CI：0.19~0.33)和0.30(95 %CI：0.18~0.41),及在国内外人群分别为0.23(95 %CI：0.17~0.29)和0.38(95 %CI：0.13~0.64)。结论 QCT比DXA对腰椎OP的检出率高,且QCT对男、女性和各年龄段及不同地区间人群的腰椎OP检出率均高于DXA,率差值随年龄的增加而增大,提示QCT对高年龄组腰椎OP的早期发现可能具有更高的价值。     

“Black Hole Artifacts”—A New Potential Pitfall for DXA Accuracy?

Certain types of metallic objects apparently have high attenuation (a white image) on dual-energy X-ray absorptiometry (DXA) scan images, but instead show up as black (black hole artifacts). When small, these artifacts may easily be missed on visual inspection. We hypothesized that such “black hole” artifacts could have a significant effect on bone mineral density (BMD) results. Human use approval (Institutional Review Board [IRB]) was obtained to publish patient scans and an IRB waiver was obtained for nonhuman research. We placed individual surgical clips and cassettes of clips of tantalum, stainless steel and titanium, and a bullet over the third lumbar vertebra (L3) of a Hologic spine phantom. In addition, 4 or 8 individual tantalum or stainless steel clips and tantalum squares were placed over L3 of cadaveric spines (high-density spine L1–L4 BMD = 1.049 g/cm²) and low-density spine BMD (L1–L4 BMD = 0.669 g/cm²) with attached soft tissues. Stainless steel and titanium clips scanned as white objects with DXA. A bullet and tantalum clips scanned black (black holes). All clip types were visible on single-energy scans as white objects. Eight tantalum clips significantly lowered L3 BMD compared to 4 or 0 clips in the high-density spine. There were no significant differences in BMD L1–L4 between 0, 4, and 8 tantalum clips in the high-density spine. In the low-density spine, 8 tantalum clips over L3 had significantly lower BMD compared to 4 tantalum clips overlying L3 and 4 clips lateral to L3 and 4 clips over L3. All of these scenarios had lower L3 BMD than no tantalum clips overlying L3. The BMD of L1–L4 was lowest with 8 clips at L3, but was not significantly different than no clips overlying L3. Eight tantalum clips lateral to L3 was significantly higher than no clips over L3. Black hole artifacts can occur in DXA scans containing certain metals like tantalum surgical clips. Although these surgical clips could decrease BMD at a localized area, they do not significantly decrease the L1–L4 spine BMD in a high-density spine specimen. In a low-density spine specimen, tantalum clips do have the potential to alter BMD of a single vertebral body and L1–L4. Attention should be paid to the possibility of black hole artifacts on DXA scans and the effect they may have on spine results. Viewing scans in the single-energy mode can be used to verify the presence of tantalum clips.     

Bone mineral density in haemodialysis patients: A comparative study of dual-energy X-ray absorptiometry and quantitative ultrasound.

BACKGROUND: Quantitative ultrasound (QUS) of bone is a relatively new technique that appears to assess 'bone quality' in addition to bone mineral density. The purpose of this study was to evaluate the diagnostic potential of QUS of calcaneum and to correlate it with dual energy X-ray absorptiometry (DEXA) in chronic haemodialysis patients. METHODS: Broad-band ultrasound attenuation (BUA; dB/MHz) and speed of sound (SOS; m/s) of calcaneum and DEXA (g/cm(2)) measurements of the lumbar spine and hip were made in 39 patients. The indices obtained by either method were compared with age-and sex-matched controls. Calcaneal measurements were correlated to DEXA and relevant clinical and biochemical data of patients. RESULTS: BUA and SOS values were markedly reduced in dialysis patients compared to controls (59.1+/-13.8 vs 73.0+/-16.2 dB/MHz, P:<0.001 and 1533+/-28 vs 1560+/-29 m/s, P:=0.014 respectively). There was a moderate, but significant association between calcaneal parameters and DEXA (r=0.32-0.53, P:<0.05). Both BUA and SOS scores were inversely correlated with age (r=-0.69, P:<0.001) and duration of menopause (r=-0.74, P:<0.01). Additionally, BUA values showed a moderate negative association with serum intact parathyroid values (r=-0.38, P:=0.018). CONCLUSION: Chronic haemodialysis patients have reduced calcaneal BUA and SOS scores. QUS of the calcaneum is an easy-to-apply and radiation-free technique. It could be a useful substitute for assessment of bone density in such patients. However, further studies in large patient groups and comparisons with plasma markers of bone turnover and bone biopsy findings are needed to assess its potential place in the management of renal osteodystrophy.     

Radiolucent Casting Tape Allows for Accurate Measurement of Forearm Bone Mineral Density Using Dual-Energy X-ray Absorptiometry

The ability to perform dual-energy X-ray absorptiometry (DXA) while a patient is in a cast would give investigators the opportunity to follow early changes in bone mineral density (BMD, g/cm2) during fracture healing or to evaluate bone changes related to immobilization. The objective of this study was to determine if accurate and precise DXA scans could be obtained through polyester-based radiolucent casting tape (Delta-Cast Elite [DCE], Johnson & Johnson, Inc., Raynham, MA) and standard fiberglass casting tape (Delta Lite [DL], Johnson & Johnson, Inc.). DXA scans were performed using a Lunar DPXL densitometer. Standard forearm regions of interest were analyzed. Ten normal volunteers had three consecutive scans of their dominant arm with no cast, with a radiolucent (DCE) cast, and with a fiberglass (DL) cast. Precision was calculated using data from three volunteers (three scans each; no cast, DCE, DL). Results of DCE and DL were compared with results with no cast. In a second series, a spine phantom was placed inside rice-filled forearm casts and repetitively scanned; results with DCE and DL were compared with the mean BMD values for the phantom alone. Analyses of the scans through the DL casts were difficult because the radiodensity of the fiberglass interfered with edge detection. This problem was exacerbated by low BMD (i.e., scans for women). Edge detection was not a problem with the DCE scans. Although the group mean BMD values with in vivo no cast, DCE, or DL scans were similar for all regions of interest, the data obtained for ultradistal regions of interest with DL scans were less precise. BMD values for the fiberglass-encased phantom were significantly lower compared with no cast or DCE scans (p = 0.0002). This study demonstrates that it is possible to perform accurate and precise forearm DXA scans through polyester-based radiolucent DCE casting tape.     

Measurement of bone mineral density of lumbar spine and whole body in low-birth-weight infants: comparison of two methods

In the present study, we compared lumbar spinal and whole-body bone mineral density (BMD) measurements to determine which is more suitable for evaluating the bone mineral status of low-birth-weight (LBW) infants. Lumbar spinal and whole-body BMD were assessed simultaneously in a prospective series including 152 Japanese LBW infants (birth weight 453–2400 g, gestational age 24–38 weeks) from the age of 40 weeks post-conception to 2 years of age. Lumbar spinal BMD at 40 weeks post-conception was significantly correlated with birth weight (r = 0.74; P < 0.0001), but whole-body BMD was not correlated with birth weight. No correlation was found between lumbar spinal and whole-body BMD at 40 weeks post-conception. However, after 40 weeks post-conception, a significant correlation was found between lumbar spinal and whole-body BMD (r = 0.65; P < 0.0001). For infants with a body weight of 4 kg or less at the time of measurement, no correlation was found between lumbar spinal and whole-body BMD. However, for infants with a body weight above 4 kg, a significant correlation was found between lumbar spinal and whole-body BMD (r = 0.65; P < 0.0001). Thus, lumbar spinal BMD is more suitable than whole-body BMD for evaluation of the bone mineral status of LBW in early infancy. Therefore, lumbar spinal BMD should be used for serial evaluation of changes in the bone mineral status of LBW infants. Received: April 6, 2000 / Accepted: June 16, 2000     

Reproducibility of Fan-Beam DXA Measurements in Adults and Phantoms

As part of a multicenter study, we examined the intersite reproducibility of bone mineral content (BMC) and areal density (BMD) among three fan-beam dual-energy X-ray absorptiometry (DXA) instruments from one manufacturer, all using the same software version. Spine, femur, and body-composition phantoms were each scanned nine times at each center. Over a 3-wk period, the same 10 adults were scanned once at each of the three centers. For the spine and femur phantoms, the precision errors were 0.3-0.7%. For the body-composition phantom, the precision errors were 0.8-2.8%. The intersite coefficients of variation for the human measurements varied from 1.1 to 6.8%, depending on the bone site. We conclude that even when using the same fan-beam DXA model and software, an intersite cross-comparison using only phantoms may be inadequate. Comparisons based solely on the use of a spine phantom are insufficient to ensure compatibility of human bone mineral data at other bone sites or for the whole body.     

Celiac Disease and Metabolic Bone Disease

Celiac disease is a common autoimmune gastrointestinal disorder affecting multiple organs, precipitated in genetically vulnerable persons by the ingestion of gluten. Gluten is poorly digested and is presented to the intestinal mucosa as a large polypeptide. Binding to human leukocyte antigen-DQ2 and human leukocyte antigen-DQ8 molecules on antigen-presenting cells stimulates cellular and humeral immune reactions. Although common serological tests are available to diagnose celiac disease, the diagnosis of celiac disease is often delayed or missed because of lack of recognition as the disease presentation in adults is highly variable and may be asymptomatic. Celiac disease is a common secondary cause of metabolic bone disease and delayed treatment with gluten-free diet affects bone mineral density and fracture risk, so it is crucial to diagnose and treat celiac disease promptly. In this article, we will review recent studies of celiac disease in adults and provide practical, easily accessible information for busy clinicians.     

Bone mineral density and turnover in patients with acromegaly in relation to sex, disease activity, and gonadal function

Acromegaly is a rare disease caused by growth hormone (GH) hypersecretion. GH and insulin-like growth factor-I (IGF-I) exert anabolic activity in bones. Nevertheless, bone mineral density (BMD) loss is not uncommon in patients with acromegaly. It is assumed to be due to hypogonadism associated with the acromegaly. The aim of the study was to examine BMD at various skeletal sites and bone turnover and to assess the influence of impaired gonadal function and disease activity on BMD and turnover changes in acromegaly. A total of 62 patients were studied (40 women, 22 men). Among the women, 22 had active disease and 18 were cured; 16 women had normal gonadal function, and 24 were hypogonadal. Altogether, 12 men presented with active acromegaly, and 10 were cured; normal gonadal function was found in 10 men, and hypogonadism was diagnosed in 12 men. Controls were 30 healthy subjects. Densitometry using dual-energy X-ray absorptiometry of the lumbar spine, proximal femur, forearm, and total body was carried out. Bone turnover was studied based on serum osteocalcin, C-terminal collagen type 1 crosslinks, and bone alkaline phosphatase concentration. A disadvantageous effect of acromegaly on bone density was associated with hypogonadism in the distal radius (in women), the proximal femur (in men), and the total body (both sexes). An anabolic effect of GH during active acromegaly was present in the proximal femur only in men. We confirmed increased bone turnover in the presence of acromegaly, and these changes were similar regarding the activity of the disease and the gonadal status.     

Regional Variation in the Denial of Reimbursement for Bone Mineral Density Testing Among US Medicare Beneficiaries

Although the Bone Mass Measurement Act outlines the indications for central dual-energy X-ray absorptiometry (DXA) testing for US Medicare beneficiaries, the specifics regarding the appropriate ICD-9 codes to use for covered indications have not been specified by Medicare and are sometimes ambiguous. We describe the extent to which DXA reimbursement was denied by gender and age of beneficiary, ICD-9 code submitted, time since previous DXA, whether the scan was performed in the physician's office and local Medicare carrier. Using Medicare administrative claims data from 1999 to 2005, we studied a 5% national sample of beneficiaries age ≥65 yr with part A + B coverage who were not health maintenance organization enrollees. We identified central DXA claims and evaluated the relationship between the factors listed above and reimbursement for central DXA (CPT code 76075). Multivariable logistic regression was used to evaluate the independent relationship between DXA reimbursement, ICD-9 diagnosis code, and Medicare carrier. For persons who had no DXA in 1999 or 2000 and who had 1 in 2001 or 2002, the proportion of DXA claims denied was 5.3% for women and 9.1% for men. For repeat DXAs performed within 23 mo, the proportion denied was approximately 19% and did not differ by sex. Reimbursement varied by more than 6-fold according to the ICD-9 diagnosis code submitted. For repeat DXAs performed at <23 mo, the proportion of claims denied ranged from 2% to 43%, depending on Medicare carrier. Denial of Medicare reimbursement for DXA varies significantly by sex, time since previous DXA, ICD-9 diagnosis code submitted, place of service (office vs facility), and local Medicare carrier. Greater guidance and transparency in coding policies are needed to ensure that DXA as a covered service is reimbursed for Medicare beneficiaries with the appropriate indications.     

Effects of skeletal size of the lumbar spine on areal bone density,volumetric bone density,and the diagnosis of osteoporosis in postmenopausal women in China

To understand the effects of skeletal size of the lumbar spine on areal bone mineral density (aBMD), volumetric bone mineral density (vBMD), and the diagnosis of osteoporosis in postmenopausal women, we measured the projected bone area, bone mineral content (BMC), aBMD, and vBMD at the anteroposterior and lateral lumbar spines in a population of 1081 postmenopausal Chinese women, 42 to 86 years of age. The results indicated that, at the anteroposterior and lateral lumbar spine, there were significant positive correlations between bone area and both BMC (r = 0.606; P = 0.000 and r = 0.610; P = 0.000) and aBMD (r = 0.270; P = 0.000 and r = 0.182; P = 0.000), but not vBMD (r = –0.055; P = 0.000 and r = 0.000; P = 0.929). When bone area at the anteroposterior spine changed by ±1 SD, the BMC, aBMD, and vBMD correspondingly changed by 28.2%, 10.1%, and 1.69% on the basis of their respective means. When a variation of ±1 SD was observed in bone area at the lateral spine, BMC and aBMD, correspondingly changed by 25.9% and 6.18% on the basis of their respective means, while vBMD indicated no change. Through comparisons among large-, intermediate-, and small-bone area groups, significant differences were found in the means of subjects heights, weights, BMC, and vBMD at the anteroposterior and lateral lumbar spines, as well as in the detection rates of osteoporosis by aBMD (P = 0.000). Detection rates of osteoporosis by aBMD at the anteroposterior spine and by aBMD at the lateral spine, and by vBMD were 44.1%, 55.5%, and 49.7%, respectively, in the total population; 31.4%, 41.7%, and 53.7%, respectively, in the large-bone area group; 43.3%, 55.9%, and 50.5%, respectively, in the intermediate-bone area group; and 61.7%, 70.0%, and 42.5%, respectively, in the small-bone area group. No significant differences were found in the detection rates of osteoporosis by vBMD among the groups. The results of multiple linear regression revealed that the major factors influencing skeletal size and aBMD of the lumbar spine were height and weight. Therefore, in menopausal women of the same ethnic group and age, the skeletal size of the lumbar spine would have significant influence upon aBMD and the diagnosis of osteoporosis, i.e., the larger the spinal size, the greater the aBMD and the lower the osteoporosis detection rate, while, conversely, the smaller the skeletal size, the smaller the aBMD and the higher the osteoporosis detection rate. When we use aBMD of the lumbar spine to diagnose osteoporosis in a population with different body sizes, we need to take this body size difference into account. When we use vBMD to diagnose osteoporosis, the effect of body size on BMD will diminish.     

Bone loss after kidney transplantation: a longitudinal study in 115 graft recipients

BACKGROUND.: Bone loss is an important problem in renal transplant recipientsimmediately after surgery. No data are available about the boneloss beyond the first post-transplantation year. METHODS.: In a longitudinal, uncontrolled observational study bone mineraldensity (BMD) was measured by dual X-ray absorptiometry in 115renal graft recipients starting at different times after transplantation(0–20 years after transplantation) with a follow-up timeof 12 months. RESULTS.: A total of 56 patients showed a reduction of BMD during theobservation period. Bone loss depended on the time after transplantation.Mean reduction of BMD at lumbar spine was 7±10%, 1±9%during the first and second postoperative year. Beyond the thirdyear bone mineral density did not change or even increased slightly(0±4% during 3–5th year, 1±6% during 6–10thyear and 2±4% during 11–20th year after transplantation).Decrease of BMD correlated with a higher mean daily prednisonedosage (P<0.001), a higher cumulative prednisone dose (P<0.01),a more frequent and more steroid-resistant rejection (P<0.001)and a higher initial parathyroid hormone level (P<0.001).Patients with 25-OH-cholecalciferol therapy (P<0.05) or morephysical activity (P<0.05) had a smaller bone loss. CONCLUSIONS.: Reduction of BMD after transplantation is highest within thefirst post-transplant year. The effects of acute graft rejection,prednisone dosage and initial parathyroid hormone level arepredominant among the multiple factors associated with pronouncedbone loss.     

晋城地区健康人群前臂骨峰值骨量的建立

目的：建立晋城地区健康人群前臂骨密度（ BMD）的峰值骨量和标准差值,为开展周围型双能X线骨密度仪测定及骨质疏松症研究提供基础数据。方法采用韩国产双能X线骨矿测量仪（ EXA－3000）对晋城地区1400例21～55岁的健康体检人群进行左侧前臂骨密度测定,进行非优势侧（左侧）前臂远端尺桡骨的BMD值测定,并分析其年龄分布,建立晋城地区健康人群前臂远端骨密度的峰值骨量和标准差值。骨质疏松的骨量诊断以骨量峰值的均数±标准差的形式建立,均数的计算采用三次方回归方程模型进行拟合。结果男、女性前臂骨的BMD值均符合正态分布,可采用均数±标准差（ xˉ±s）的形式表示。40岁以前男、女性前臂骨的BMD值均随年龄增加而逐步上升,且各年龄段BMD值的差异有统计学意义（P＜0．05）。45岁以后男、女性前臂骨的BMD值开始下降,且50岁以后下降明显（ P＜0．05）。男、女性前臂骨的骨量峰值均出现在41～45岁年龄段。男、女性前臂远端尺桡骨的骨量峰值及标准差分别为（0．5682±0．0647）g／cm2、（0．4209±0．0689）g／cm2。结论建立了晋城地区健康人群男、女性前臂骨的骨量峰值和标准差,为周围型双能X线骨密度仪测定并开展骨质疏松症的研究提供基础数据,尤其是用于高危人群筛查,以便确定是否需要进一步开展中轴骨测量或进行药物治疗。     

DXA Scanning of Acetabulum in Patients With Cementless Total Hip Arthroplasty

The aim of this study was to evaluate the reproducibility of bone mineral density (BMD) measurements of the periprosthetic bone in patients with hemispherical acetabular cups in cementless total hip arthroplasty (THA). Thirty patients were treated for primary osteoarthrosis with cementless THA. Dual-energy X-ray absorptiometry (DXA) scanning was performed with a pencil-beam bone densitometer (Norland XR-36). Accuracy and reproducibility was determined by double measurements of BMD in four regions of interest (ROI). The influence of patient postures including various pelvic inclination angles was evaluated as well. Pitman test for a combined netROI revealed a standard deviation ratio of 3.2 for the anterio-posterior scans related to the lateral position. The Wilkinson ROIs showed a high intraobserver agreement. With pelvic tilt increasing until 20 degrees , the precision of DXA scanning decreased. In conclusion, reproducibility of DXA scanning was high. This study demonstrated that the patients can be scanned in the supine position, and BMD measurement of the periacetabular bone can be performed using the Wilkinson model with four rectangular ROIs.