Trabecular bone mineral density as measured by thoracic vertebrae predicts incident hip and vertebral fractures: the multi-ethnic study of atherosclerosis

We evaluated the relationship of bone mineral density (BMD) by computed tomography (CT), to predict fractures in a multi-ethnic population. We demonstrated that vertebral and hip fractures were more likely in those patients with low BMD. This is one of the first studies to demonstrate that CT BMD derived from thoracic vertebrae can predict future hip and vertebral fractures.

PURPOSE/INTRODUCTION

Osteoporosis affects an enormous number of patients, of all races and both sexes, and its prevalence increases as the population ages. Few studies have evaluated the association between the vertebral trabecular bone mineral density(vBMD) and osteoporosis-related hip fracture in a multiethnic population, and no studies have demonstrated the predictive value of vBMD for fractures.

METHOD

We sought to determine the predictive value of QCT-based trabecular vBMD of thoracic vertebrae derived from coronary artery calcium scan for hip fractures in the Multi-Ethnic Study of Atherosclerosis(MESA), a nationwide multicenter cohort included 6814 people from six medical centers across the USA and assess if low bone density by QCT can predict future fractures. Measures were done using trabecular bone measures, adjusted for individual patients, from three consecutive thoracic vertebrae (BDI Inc, Manhattan Beach CA, USA) from non-contrast cardiac CT scans.

RESULTS

Six thousand eight hundred fourteen MESA baseline participants were included with a mean age of 62.2 ± 10.2 years, and 52.8% were women. The mean thoracic BMD is 162.6 ± 46.8 mg/cm3 (95% CI 161.5, 163.7), and 27.6% of participants (n = 1883) had osteoporosis (T-score 2.5 or lower). Over a median follow-up of 17.4 years, Caucasians have a higher rate of vertebral fractures (6.9%), followed by Blacks (4.4%), Hispanics (3.7%), and Chinese (3.0%). Hip fracture patients had a lower baseline vBMD as measured by QCT than the non-hip fracture group by 13.6 mg/cm3 [P < 0.001]. The same pattern was seen in the vertebral fracture population, where the mean BMD was substantially lower 18.3 mg/cm3 [P < 0.001] than in the non-vertebral fracture population. Notably, the above substantial relationship was unaffected by age, gender, race, BMI, hypertension, current smoking, medication use, or activity. Patients with low trabecular BMD of thoracic vertebrae showed a 1.57-fold greater risk of first hip fracture (HR 1.57, 95% CI 1.38-1.95) and a nearly threefold increased risk of first vertebral fracture (HR 2.93, 95% CI 1.87-4.59) compared to normal BMD patients.

CONCLUSION

There is significant correlation between thoracic trabecular BMD and the incidence of future hip and vertebral fracture. This study demonstrates that thoracic vertebrae BMD, as measured on cardiac CT (QCT), can predict both hip and vertebral fractures without additional radiation, scanning, or patient burden. Osteopenia and osteoporosis are markedly underdiagnosed. Finding occult disease affords the opportunity to treat the millions of people undergoing CT scans every year for other indications.

The utility of quantitative computed tomography in cohort studies of chronic obstructive pulmonary disease: a narrative review

Background and Objective

Chronic obstructive pulmonary disease (COPD) is a significant contributor to global morbidity and mortality. Quantitative computed tomography (QCT), a non-invasive imaging modality, offers the potential to assess lung structure and function in COPD patients. Amidst the coronavirus disease 2019 (COVID-19) pandemic, chest computed tomography (CT) scans have emerged as a viable alternative for assessing pulmonary function (e.g., spirometry), minimizing the risk of aerosolized virus transmission. However, the clinical application of QCT measurements is not yet widespread enough, necessitating broader validation to determine its usefulness in COPD management.

Methods

We conducted a search in the PubMed database in English from January 1, 2013 to April 20, 2023, using keywords and controlled vocabulary related to QCT, COPD, and cohort studies.

Key Content and Findings

Existing studies have demonstrated the potential of QCT in providing valuable information on lung volume, airway geometry, airway wall thickness, emphysema, and lung tissue density in COPD patients. Moreover, QCT values have shown robust correlations with pulmonary function tests, and can predict exacerbation risk and mortality in patients with COPD. QCT can even discern COPD subtypes based on phenotypic characteristics such as emphysema predominance, supporting targeted management and interventions.

Conclusions

QCT has shown promise in cohort studies related to COPD, since it can provide critical insights into the pathogenesis and progression of the disease. Further research is necessary to determine the clinical significance of QCT measurements for COPD management.

Association Between Hip Bone Mineral Density and Mortality Risk After Hip Fracture: A Prospective Cohort Study

Factors related to mortality after osteoporotic hip fracture (HF) have been investigated intensively, except for proximal femoral bone mineral density (BMD), which is also the primary cause of osteoporosis. In this study, we aimed to investigate the association of hip BMD with mortality risk after HF. Four hundred and eleven elderly patients with HF in Beijing, China, were included and prospectively followed up with a median time of 3 years. At baseline, quantitative CT technique (QCT) was used to measure areal BMD (aBMD) of the unaffected hip. Areal BMDs of the total hip (TH), femoral neck (FN), trochanter (TR), and intertrochanter were analyzed with postoperative mortality as the primary outcome. A total of 394 patients (78.59 ± 7.59 years, 75.4% female) were included in our final analysis, with 86 (82.23 ± 7.00 years, 81.4% female) dead. All hip bone densities demonstrated a significant association with mortality risks in the unadjusted model, but only TR aBMD remained significantly correlated after adjusting for all covariates. Compared to the lower TR aBMD group, the higher TR aBMD group yielded significantly lower death risks (HR 0.21 95% CI 0.05-0.9, P = 0.036). Higher survival probabilities were observed for higher TH and TR aBMD in survival analysis (P < 0.001). Hip BMD, especially TR BMD assessed by QCT, is an independent risk factor for postoperative mortality following HF. QCT may present a promising avenue for opportunistic analysis in immobilized patients, providing valuable information for early detection and personalized interventions to enhance patient outcomes.

MRI-based vertebral bone quality score compared to quantitative computed tomography bone mineral density in patients undergoing cervical spinal surgery

PURPOSE

The vertebral bone quality (VBQ) score based on magnetic resonance imaging (MRI) was introduced as a bone quality marker in the lumbar spine. Prior studies showed that it could be utilized as a predictor of osteoporotic fracture or complications after instrumented spine surgery. The objective of this study was to evaluate the correlation between VBQ scores and bone mineral density (BMD) measured by quantitative computer tomography (QCT) in the cervical spine.

METHODS

Preoperative cervical CT and sagittal T1-weighted MRIs from patients undergoing ACDF were retrospectively reviewed and included. The VBQ score in each cervical level was calculated by dividing the signal intensity of the vertebral body by the signal intensity of the cerebrospinal fluid on midsagittal T1-weighted MRI images and correlated with QCT measurements of the C2-T1 vertebral bodies. A total of 102 patients (37.3% female) were included.

RESULTS

VBQ values of C2-T1 vertebrae strongly correlated with each other. C2 showed the highest VBQ value [Median (range) 2.33 (1.33, 4.23)] and T1 showed the lowest VBQ value [Median (range) 1.64 (0.81, 3.88)]. There was significant weak to moderate negative correlations between and VBQ Scores for all levels [C2: p < 0.001; C3: p < 0.001; C4: p < 0.001; C5: p < 0.004; C6: p < 0.001; C7: p < 0.025; T1: p < 0.001].

CONCLUSION

Our results indicate that cervical VBQ scores may be insufficient in the estimation of BMDs, which might limit their clinical application. Additional studies are recommended to determine the utility of VBQ and QCT BMD to evaluate their potential use as bone status markers.

Peripheral cortical bone density predicts vertebral bone mineral properties in spine fusion surgery patients

Spine fusion surgery is one of the most common orthopedic procedures, with over 400,000 performed annually to correct deformities and pain. However, complications occur in approximately one third of cases. While many of these complications may be related to poor bone quality, it is difficult to detect bone abnormalities prior to surgery. Areal BMD (aBMD) assessed by DXA may be artifactually high in patients with spine pathology, leading to missed diagnosis of deficits. In this study, we related preoperative imaging characteristics of both central and peripheral sites to direct measurements of bone quality in vertebral biopsies. We hypothesized that pre-operative imaging outcomes would relate to vertebral bone mineralization and collagen properties. Pre-operative assessments included DXA measurements of aBMD of the spine, hip, and forearm, central quantitative computed tomography (QCT) of volumetric BMD (vBMD) at the lumbar spine, and high resolution peripheral quantitative computed tomography (HRpQCT; Xtreme CT2) measurements of vBMD and microarchitecture at the distal radius and tibia. Bone samples were collected intraoperatively from the lumbar vertebrae and analyzed using Fourier-transform Infrared (FTIR) spectroscopy. Bone samples were obtained from 23 postmenopausal women (mean age 67 ± 7 years, BMI 28 ± 8 kg/m2). We found that patients with more mature bone by FTIR, measured as lower acid phosphate content and carbonate to phosphate ratio, and greater collagen maturity and mineral maturity/crystallinity (MMC), had greater cortical vBMD at the tibia and greater aBMD at the lumbar spine and one-third radius. Our data suggests that bone quality at peripheral sites may predict bone quality at the spine. As bone quality at the spine is challenging to assess prior to surgery, there is a great need for additional screening tools. Pre-operative peripheral bone imaging may provide important insight into vertebral bone quality and may foster identification of patients with bone quality deficits.

Dietary Saturated Fat and Bone Health in Young Adults: The Young Finns Cohort

Previous studies suggest that saturated fat (SFA) intake may negatively impact on bone. However, few human studies on the topic exist. Women and men aged 31-46 years from the Cardiovascular Risk in Young Finns study attended the peripheral quantitative computed tomography and ultrasound bone measurements in 2008 (n = 1884-1953, ~ 56% women). In addition, fracture diagnoses in 1980-2018 were searched for the national health care registers and 431 participants had at least one fracture. Food consumption was gathered with the 48-h dietary recall interviews and food frequency questionnaire in 1980-2007. In the present study, radial, tibial, and calcaneal bone traits, and fractures were examined relative to the long-term intake of SFA. No consistent associations were seen between bone outcomes and SFA intake that would have replicated in both women and men. The only evidence for differential distributions was seen in cortical density and cortical-to-total area ratio at the radial shaft, and speed of sound at the calcaneus, which were 0.1-0.4% higher in women in the lowest tertile of SFA intake compared with the highest tertile. In addition, among men, the odds ratio (OR) of fractures was greater in the second (OR 1.86, 95% confidence interval (CI) 1.03-3.33) and third tertile of SFA intake (OR 2.45, 95% CI 1.38-4.36) compared with the lowest tertile, independently of many risk factors of osteoporosis. In this observational study, we found no robust evidence of the associations of dietary long-term SFA intake with bone outcomes. Therefore, additional studies are needed to confirm the association of dietary SFA with bone health in humans.

Relationship of abdominal aortic calcification with lumbar vertebral volumetric bone mineral density assessed by quantitative computed tomography in maintenance hemodialysis patients

INTRODUCTION

This cross-sectional study aimed to investigate the relationship between abdominal aortic calcification (AAC), which is a marker of vascular calcification, and volumetric bone mineral density (vBMD) by quantitative computed tomography (QCT) in maintenance hemodialysis (MHD) patients.

METHODS

All participants underwent lumbar vertebral vBMD measurement by QCT. Eight cross-sections were extracted sequentially and analyzed by ImageJ software to obtain the ratio of the calcified area to the abdominal aortic area (the calcification ratio). The AAC score was determined by the sum of the calcification ratios. The relationship between AAC and vBMD was analyzed using multivariate logistic regression.

RESULTS

Ninety MHD patients (58.89% male) with a mean age of 63.43 (standard deviation [SD] = 13.20) years were included in the study. AAC was present (AAC score > 0) in 93.33% of the patients. The 75th percentile of the AAC score corresponding to 119 was used as the cutoff point between the mild and severe groups. After full adjustment in the logistic model, AAC was found to be inversely associated with vBMD (odds ratio [OR], 0.970; 95% confidence interval [CI], 0.944 to 0.996; P = 0.025), and patients with osteoporosis had a significantly higher risk of severe AAC than those with normal bone mass (OR, 14.498; 95% CI, 1.507 to 139.486; P = 0.021). The independent inverse association was still stable after adjusting for variables measured at different time periods and using different cutoff points of the AAC score.

CONCLUSION

There was an independent inverse association between AAC and vBMD, and osteoporosis was significantly associated with severe AAC in patients with MHD.

Impact of sleeve gastrectomy on bone outcomes in adolescents vs. adults with obesity

BACKGROUND

Sleeve gastrectomy (SG) is the most common metabolic and bariatric surgery (MBS) procedure in adolescents and adults. Only few studies have assessed bone outcomes following SG and it is unknown whether skeletal changes differ by age group. Recent studies have identified marrow adipose tissue (MAT) as a novel biomarker for bone quality with studies in adults showing high MAT in those with visceral adiposity and a reciprocal increase in MAT with bone loss.

OBJECTIVE

To determine the impact of SG on volumetric BMD (vBMD) and MAT in adolescents and adults with obesity. We hypothesized that SG would lead to a decrease in vBMD and increase in MAT but that these changes would be less pronounced in adolescents compared to adults.

MATERIALS AND METHODS

The study was IRB-approved and HIPAA-compliant. Written informed consent/assent was obtained. We examined 10 adolescents (mean age 17.8 ± 2.5 years, mean BMI 43.5 ± 5.6 kg/m²) and 10 sex, race, and BMI-matched adults (mean age 49.5 ± 13.6 years, mean BMI 43.7 ± 5.9 kg/m²), before and 12 months after SG. At baseline and 12 months, subjects underwent quantitative CT of the lumbar spine (L1-L2) to assess trabecular vBMD, single voxel proton MR spectroscopy at 3 T (PRESS pulse sequence without water suppression) at L1-L2 to quantify MAT, and MRI of the abdomen to assess visceral (VAT) and subcutaneous adipose tissue (SAT).

RESULTS

At baseline, adolescents had lower MAT (p = 0.0002) and higher vBMD (p = 0.050) compared to adults. Adolescents and adults lost 27.9 ± 6.5 vs. 25.0 ± 11.2% of body weight (p < 0.0001 for within group change), while there was no significant difference between groups (p = 0.455). There was a significant reduction in vBMD in adults (-3.9 ± 3.9%, p = 0.005) and a trend for a reduction in adolescents (-3.7 ± 7.5%, p = 0.119), with no significant difference between groups (p = 0.944). Lumbar MAT content increased in both adults and adolescents (p ≤ 0.034), while the difference was not significant between groups (p = 0.281). In adolescents and adults, 12-month percent change in weight and BMI was positively associated with % change in MAT (p ≤ 0.042). 12-month percent change in MAT was positively associated with 12-month % change in SAT in adolescents and 12-month percent change in VAT in adults (p ≤ 0.045).

CONCLUSION

SG in adolescents and adults with severe obesity is associated with a reduction in lumbar vBMD and an increase in lumbar MAT, although the reduction in adolescents did not reach statistical significance, with no significant differences in these endpoints between groups. Our results suggest detrimental effects of bariatric surgery on bone for patients across the life span.

Relationships between anthropometric adiposity indexes and bone mineral density in a cross-sectional Chinese study

BACKGROUND CONTEXT

Previous studies have reported conflicting results for the relationships between anthropometric adiposity indexes and bone mineral density, based on dual-energy X-ray absorptiometry (DXA). However, few studies were published based on quantitative computed tomography (QCT), especially for Chinese population.

PURPOSE

To evaluate the associations of spine bone mineral density (BMD) with body mass index (BMI), waist circumstance (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and a body shape index (ABSI) using QCT.

STUDY DESIGN/SETTING

A Cross-sectional study.

PATIENT SAMPLE

Around 3,457 participants in multiple communities across 7 administrative regions of China.

OUTCOME MEASURES

Spine BMD was measured using QCT, and the classification of osteoporosis was defined as follows: 1) osteoporosis if BMD <80mg/cm³, 2) osteopenia if BMD 80-119 mg/cm³, and 3) normal bone mass if BMD≥120 mg/cm³.

METHODS

This study was conducted using convenient sampling between 2013 and 2017. Multivariable linear regression model and logistic regression models were used for the associations of continuous and categorical BMD, respectively.

RESULTS

Around 3,405 participants were included in the final analyses, including 1,272 males and 2,133 females, with spine BMD of 111.00±35.47 mg/cm³ and 99.38±40.60 mg/cm³, respectively. Spine BMD decreased significantly with the increase of ABSI in females (adjusted β, -5.74; 95% confidence interval [CI], -8.50 to -2.98), and this trend also was kept in females aged at less than 60 years (adjusted β, -14.54; 95% CI, -20.40 to -8.68), and females with age ≥60 years (adjusted β, -7.59; 95% CI, -10.91 to -4.28). However, this inverse association was observed only in males with age ≥ 60 years (adjusted β, -5.19; 95% CI, -10.08 to -0.29). Except ABSI, negative associations of Spine BMD with WC (adjusted β, -0.46; 95% CI, -0.77 to -0.15), WHR (adjusted β, -6.25; 95% CI, -10.63 to -1.86), WHtR (adjusted β, -6.80; 95% CI, -11.63 to -1.97) were shown in females aged at <60 years, and positive association with BMI in males with age ≥60 years (adjusted β, 0.92; 95% CI, 0.29-1.55).

CONCLUSIONS

ABSI had more remarkable association with spine BMD, compared with the other four indexes.

Quantitative CT-based image registration metrics provide different ventilation and lung motion patterns in prone and supine positions in healthy subjects

Background

Previous studies suggested that the prone position (PP) improves oxygenation and reduces mortality among patients with acute respiratory distress syndrome (ARDS). However, the mechanism of this clinical benefit of PP is not completely understood. The aim of the present study was to quantitatively compare regional characteristics of lung functions in the PP with those in the supine position (SP) using inspiratory and expiratory computed tomography (CT) scans.

Methods

Ninety subjects with normal pulmonary function and inspiration and expiration CT images were included in the study. Thirty-four subjects were scanned in PP, and 56 subjects were scanned in SP. Non-rigid image registration-based inspiratory-expiratory image matching assessment was used for regional lung function analysis. Tissue fractions (TF) were computed based on the CT density and compared on a lobar basis. Three registration-derived functional variables, relative regional air volume change (RRAVC), volumetric expansion ratio (J), and three-dimensional relative regional displacement (s*) were used to evaluate regional ventilation and deformation characteristics.

Results

J was greater in PP than in SP in the right middle lobe (P = 0 .025), and RRAVC was increased in the upper and right middle lobes (P < 0.001). The ratio of the TF on inspiratory and expiratory scans, J, and RRAVC at the upper lobes to those at the middle and lower lobes and that ratio at the upper and middle lobes to those at the lower lobes of were all near unity in PP, and significantly higher than those in SP (0.98–1.06 vs 0.61–0.94, P < 0.001).

Conclusion

We visually and quantitatively observed that PP not only induced more uniform contributions of regional lung ventilation along the ventral-dorsal axis but also minimized the lobar differences of lung functions in comparison with SP. This may help in the clinician’s search for an understanding of the benefits of the application of PP to the patients with ARDS or other gravitationally dependent pathologic lung diseases.

Trial registration

Retrospectively registered.

Quantitative computed tomography discriminates between postmenopausal women with low spine bone mineral density with vertebral fractures and those with low spine bone mineral density only: the SHATTER study

Lumbar spine volumetric bone mineral density (BMD) measured using quantitative computed tomography (QCT) can discriminate between postmenopausal women with low areal BMD with and without vertebral fractures. QCT provides a 3D measure of BMD, excludes the vertebral posterior elements and accounts for bone size. This knowledge could contribute to effective treatment targeting of patients with low BMD.

INTRODUCTION

We evaluated the ability of lumbar spine bone mineral apparent density (BMAD), trabecular bone score (TBS) and volumetric bone mineral density (vBMD) to discriminate between postmenopausal women with low areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) with and without vertebral fractures. The discriminatory ability of lumbar spine aBMD was compared with that of BMAD, TBS and vBMD.

METHODS

We studied three groups of postmenopausal women, i.e. group 1, aBMD T-score < - 1.0 and ≥ 1 vertebral fracture (n = 39); group 2, aBMD T-score < - 1.0 and no vertebral fracture, age- and aBMD-matched to group 1 (n = 34); group 3, aBMD score > - 1 and no vertebral fracture, age-matched to group 1 (n = 37). Lumbar spine aBMD was measured by DXA. BMAD was calculated using the DXA scan results. TBS was derived following DXA scan image reanalysis. Lumbar spine vBMD was assessed by quantitative computed tomography and Mindways Pro software. Differences in variables between groups 1, 2 and 3 were examined using general linear univariate modelling approaches. Area under the receiver operating characteristic (ROC) curve was calculated for BMAD, TBS and vBMD to determine the ability of lumbar spine measurement variables to discriminate between group 1 and group 2. A comparison of ROCs was performed.

RESULTS

Lumbar spine BMAD and TBS measurement variables were similar for groups 1 and 2. However, vBMD was significantly lower in group 1 and could discriminate between those women with low aBMD with (group 1) and without vertebral fractures (group 2).

CONCLUSIONS

We conclude that lumbar spine vBMD may discriminate well between postmenopausal women with low aBMD with and without vertebral fractures as it provides a 3D measure of bone mineral density, excludes the posterior elements of the vertebrae and takes into account bone size. A unique feature of the SHATTER study is that groups 1 and 2 were matched for aBMD, thus our study findings are independent of aBMD. Furthermore, we observed that neither BMAD nor TBS could distinguish between women with low aBMD with and without vertebral fractures. The knowledge gained from the SHATTER study will influence clinical and therapeutic decision-making, thereby optimising the care of patients with and without vertebral and other fragility fractures.

Relationship of volumetric bone mineral density by quantitative computed tomography with abdominal aortic calcification

OBJECTIVE

This multicenter study aimed to evaluate the association between volumetric bone mineral density (vBMD) and abdominal aortic calcification (AAC) in a Chinese population.

METHODS

Quantitative computed tomography (QCT) and Agatston score (AS) were used to measure vBMD and AAC, respectively, in 3457 participants during 2013-2017. The association between vBMD and AAC was assessed using multivariate regression analysis, adjusted for age, residence, education, body mass index, and other cardiovascular risk factors.

RESULTS

The mean age of women and men was 61.4 and 62.7 years, respectively. In total, 30.4% of women and 37.7% of men were found to have AAC. After full adjustment, higher vBMD was associated with lower AAC score (β, -0.095; 95% confidence interval [CI], -0.167 to -0.024; P = 0.0087) and lower AAC prevalence (odds ratio [OR], 0.873; 95% CI, 0.824 to 0.924; P < 0.0001) in men. Inverse trends were also observed in the association of vBMD quartile with AAC severity (lowest vs highest quartile; β = 0.235; 95% CI, 0.011 to 0.459; P_trend < 0.0001) and AAC prevalence (lowest vs highest quartile; OR = 1.329; 95% CI, 1.087 to 1.625; P_trend < 0.0001) in men. However, no significant result was obtained in women, except for the association between quartiles of vBMD and AAC score.

CONCLUSIONS

In our study, vBMD was inversely associated with AAC among men independent of age and shared risk factors. However, the association was not significant among women.

Quantitative computed tomography analysis for stratifying the severity of Coronavirus Disease 2019

To examine the feasibility of using a computer tool for stratifying the severity of Coronavirus Disease 2019 (COVID-19) based on computed tomography (CT) images. We retrospectively examined 44 confirmed COVID-19 cases. All cases were evaluated separately by radiologists (visually) and through an in-house computer software. The degree of lesions was visually scored by the radiologist, as follows, for each of the 5 lung lobes: 0, no lesion present; 1, <1/3 involvement; 2, >1/3 and < 2/3 involvement; and 3, >2/3 involvement. Lesion density was assessed based on the proportion of ground-glass opacity (GGO), consolidation and fibrosis of the lesions. The parameters obtained using the computer tool included lung volume (mL), lesion volume (mL), lesion percentage (%), and mean lesion density (HU) of the whole lung, right lung, left lung, and each lobe. The scores obtained by the radiologists and quantitative results generated by the computer software were tested for correlation. A Chi-square test was used to test the consistency of radiologist- and computer-derived lesion percentage in the right/left lung, upper/lower lobe, and each of the 5 lobes. The results showed a strong to moderate correlation between lesion percentage scores obtained by radiologists and the computer software (r ranged from 0.7679 to 0.8373, P < 0.05), and a moderate correlation between the proportion of GGO and mean lesion density (r = −0.5894, P < 0.05), and proportion of consolidation and mean lesion density (r = 0.6282, P < 0.05). Computer-aided quantification showed a statistical significant higher lesion percentage for lower lobes than that assessed by the radiologists (χ² = 8.160, P = 0.004). Our experiments demonstrated that the computer tool could reliably and accurately assess the severity and distribution of pneumonia on CT scans.

•

Lesion percentage calculated by computer and radiologist are highly correlated.

•

Lesion density quantifiedby computer was correlated with the visually scored proportion of ground glass opacity and consolidation.

•

The computer tool could reliably and accurately assess the distribution of pneumonia.

Hounsfield Units on Lumbar Computed Tomography for Predicting Regional Bone Mineral Density

Objective

Bone mineral density (BMD) is a very important factor in spinal fusion surgery using instrumentation. Our aim was to investigate the utility of Hounsfield units (HU) obtained from preoperative lumbar computed tomography (CT) to predict osteoporosis coupling with data of quantitative computed tomography (QCT) and dual X-ray absorptiometry (DEXA).

Methods

We reviewed 180 patients that underwent both QCT and lumbar CT for spine surgery. HU was retrospectively calculated on the lumbar CT of 503 lumbar vertebrae from L1 to L3. Femur DEXA was performed in all patients and spine DEXA was tested in 120 patients (331 vertebrae). BMD was grouped as osteoporosis (QCT<80mg/cm³, DEXA T score≤-2.5) and non-osteoporosis (QCT≥80mg/cm³, DEXA T score>-2.5) for comparison of HU value.

Results

HU value and BMD showed significant correlations. The optima cut-off value based on QCT was higher than that of DEXA scans which had the best correlation for predicting osteoporosis. ROC curve analysis demonstrated that HU value with QCT of 146 has a sensitivity of 94.3% and a specificity of 87.5% for osteoporosis.

Conclusions

Significant correlation was found between HU measurement and BMD value. These findings provide evidence that HU measurement can be established as a means for predicting osteoporosis before spine fusion surgery with reduced radiation hazard.

Hip Fracture Discrimination Based on Statistical Multi-parametric Modeling (SMPM)

Studies using quantitative computed tomography (QCT) and data-driven image analysis techniques have shown that trabecular and cortical volumetric bone mineral density (vBMD) can improve the hip fracture prediction of dual-energy X-ray absorptiometry areal BMD (aBMD). Here, we hypothesize that (1) QCT imaging features of shape, density and structure derived from data-driven image analysis techniques can improve the hip fracture discrimination of classification models based on mean femoral neck aBMD (Neck.aBMD), and (2) that data-driven cortical bone thickness (Ct.Th) features can improve the hip fracture discrimination of vBMD models. We tested our hypotheses using statistical multi-parametric modeling (SMPM) in a QCT study of acute hip fracture of 50 controls and 93 fragility fracture cases. SMPM was used to extract features of shape, vBMD, Ct.Th, cortical vBMD, and vBMD in a layer adjacent to the endosteal surface to develop hip fracture classification models with machine learning logistic LASSO. The performance of these classification models was evaluated in two aspects: (1) their hip fracture classification capability without Neck.aBMD, and (2) their capability to improve the hip fracture classification of the Neck.aBMD model. Assessments were done with 10-fold cross-validation, areas under the receiver operating characteristic curve (AUCs), differences of AUCs, and the integrated discrimination improvement (IDI) index. All LASSO models including SMPM-vBMD features, and the majority of models including SMPM-Ct.Th features performed significantly better than the Neck.aBMD model; and all SMPM features significantly improved the hip fracture discrimination of the Neck.aBMD model (Hypothesis 1). An interesting finding was that SMPM-features of vBMD also captured Ct.Th patterns, potentially explaining the superior classification performance of models based on SMPM-vBMD features (Hypothesis 2). Age, height and weight had a small impact on model performances, and the model of shape, vBMD and Ct.Th consistently yielded better performances than the Neck.aBMD models. Results of this study clearly support the relevance of bone density and quality on the assessment of hip fracture, and demonstrate their potential on patient and healthcare cost benefits.

Sex differences in the spatial distribution of bone in relation to incident hip fracture: Findings from the AGES-Reykjavik study

In this case-cohort study, we used data-driven computational anatomy approaches to assess within and between sex spatial differences in proximal femoral bone characteristics in relation to incident hip fracture. One hundred male and 234 female incident hip fracture cases, and 1047 randomly selected noncase subcohort participants (562 female) were chosen from the population-based AGES-Reykjavik study (mean age of 77 years). The baseline -i.e. before hip fracture- hip quantitative computed tomography scans of these subjects were analyzed using voxel-based morphometry, tensor-based morphometry, and surface-based statistical parametric mapping to assess the spatial distribution of volumetric bone mineral density (vBMD), internal structure, and cortical bone properties (thickness, vBMD and trabecular vBMD adjacent to the endosteal surface) of the proximal femur, respectively, in relation to incident hip fracture. Results showed that in both men and women: 1) the superior aspect of the femoral neck and the trochanteric region (except for cortical bone thickness) were consistently identified as being associated with incident hip fracture, and 2) differences in bone properties between noncases and incident hip fracture cases followed similar trends, were located at compatible regions, and manifested heterogeneity in the spatial distribution of their magnitude with focal regions showing larger differences. With respect to sex differences, most of the regions with a significant interaction between fracture group and sex showed: 1) differences of greater magnitude in men between noncases and incident hip fracture cases with different spatial distributions for all bone properties with the exception of cortical bone thickness, and 2) that while most of these regions showed better bone quality in male cases than in female cases, female cases showed higher vBMD in the principal compressive group and higher endotrabecular vBMD at several regions including the anterior, posterior, and lateral aspects of the proximal femur. These findings indicate the value of these image analysis techniques by providing unique information about the specific patterns of bone deterioration associated with incident hip fracture and their sex differences, highlighting the importance of looking to men and women separately in the assessment of hip fracture risk.

Serum Concentration of Macro-, Micro-, and Trace Elements in Silver Fox (Vulpes vulpes) and Their Interrelationships with Morphometric, Densitometric, and Mechanical Properties of the Mandible

The optimal content of macro-, micro-, and trace elements in tissues ensures proper systemic growth and development and optimal health status in animals and humans. However, very little is known on the elemental content in the plasma compartment in Silver fox. The aim of this study was to determine the content of selected elements in serum obtained from 8-month-old female (N = 8) and male (N = 7) silver foxes. Moreover, relationships of the evaluated elements with the morphological, densitometric, and mechanical parameters of the mandible were determined. Serum content of 12 different elements was measured using inductively coupled plasma-atomic emission spectrometry. The morphometric and densitometric properties of the mandible were determined using quantitative computed tomography method, while mechanical endurance was tested using a three-point bending test. Serum concentration of calcium was significantly higher by 20% in male foxes (P = 0.01), while manganese concentration was significantly lower in males by over 17% (P = 0.03). Positive correlations of serum concentration of calcium, phosphorus, and magnesium with the morphological traits of the mandible such as weight, length, and bone volume were stated (P < 0.05). In the group of elements playing regulatory functions, the positive relationships between serum concentrations of selenium, chromium, manganese, copper, and cobalt were found (P < 0.05). The elaborated experimental model may serve for further studies on foxes, especially focused on nutritional factors affecting elemental homeostasis, whole-body metabolism, and systemic growth and development. Daily diet formulation and precise delivery for farm foxes, together with relatively large animal population maintained at the same environmental conditions, regularly subjected to slaughter procedure, enable economical experimentation with various dietary and pharmacological manipulations.

Fracture Prediction by Computed Tomography and Finite Element Analysis: Current and Future Perspectives

PURPOSE OF REVIEW

This review critiques the ability of CT-based methods to predict incident hip and vertebral fractures.

RECENT FINDINGS

CT-based techniques with concurrent calibration all show strong associations with incident hip and vertebral fracture, predicting hip and vertebral fractures as well as, and sometimes better than, dual-energy X-ray absorptiometry areal biomass density (DXA aBMD). There is growing evidence for use of routine CT scans for bone health assessment. CT-based techniques provide a robust approach for osteoporosis diagnosis and fracture prediction. It remains to be seen if further technical advances will improve fracture prediction compared to DXA aBMD. Future work should include more standardization in CT analyses, establishment of treatment intervention thresholds, and more studies to determine whether routine CT scans can be efficiently used to expand the number of individuals who undergo evaluation for fracture risk.

Thoracic Quantitative Computed Tomography (QCT) Can Sensitively Monitor Bone Mineral Metabolism: Comparison of Thoracic QCT vs Lumbar QCT and Dual-energy X-ray Absorptiometry in Detection of Age-relative Change in Bone Mineral Density

RATIONALE AND OBJECTIVE

Sensitive detection of bone mineral density (BMD) change is a key issue to monitor and evaluate the individual bone health status, as well as bone metabolism and bone mineral status. The ability to use thoracic quantitative computed tomography (QCT) to detect the annual change of BMD remains unclear. We aimed to investigate the sensitivity in detecting age-related bone mineral loss using the thoracic QCT from the electrocardiographically gated heart scans in comparison to whole-body dual-energy X-ray absorptiometry (DXA) and standard lumbar QCT.

MATERIALS AND METHODS

A total of 121 asymptomatic patients' imaging data, including DXA whole body scan, cardiac CT scan, and abdomen scans were analyzed. The BMD of the thoracolumbar spine, upper, and lower extremities were measured using QCT and DXA, respectively. The age-related annual rate of bone density loss was computed and compared to the thoracic and lumbar QCT, as well DXA measures.

RESULTS

The age-related annual rate of bone loss with QCT was -0.70 mg/mL³ (-0.75%/y) in women, -0.83 mg/mL³ (-0.86%/y) in men in the thoracic and the lumbar trabecular QCT, respectively. Compared to the QCT, DXA demonstrates a lower annual rate of bone loss in the area of BMD measurement (P < .05 in all, excluding legs of women) in -0.45, -0.42, -0.67, and -0.46 in women, in -0.32, -0.02, -0.12, and -0.08 in men for thoracic, lumbar, leg, and arm, respectively.

CONCLUSION

We conclude that the thoracic and the lumbar QCT provide a similar and more sensitive method for detecting bone mineral loss when compared to DXA.

Marrow adipose tissue composition in adults with morbid obesity

Patients with type 2 diabetes mellitus (T2DM) have increased fracture risk despite normal or increased bone mineral density (BMD). Elevations in marrow adipose tissue (MAT) and declines in MAT unsaturation are both associated with increased skeletal fragility. The objective of our study was to characterize the quantity and composition of MAT in adults with morbid obesity and T2DM, and to evaluate determinants of MAT. We studied 21 adults with morbid obesity prior to bariatric surgery, 8 of whom had T2DM. All subjects underwent 1H-MR spectroscopy of the lumbar spine and femur for assessment of MAT and dual-energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT) of the lumbar spine and hip for assessment of areal BMD (aBMD) and volumetric BMD (vBMD). Visceral (VAT) and subcutaneous adipose tissue (SAT) were quantified by CT at L1-L2. Subjects with T2DM had higher vBMD of the femoral neck and higher total MAT at the lumbar spine and femoral metaphysis compared to non-diabetic controls (p≤0.04). Lipid unsaturation index (UI) was significantly lower at the femoral diaphysis in T2DM (p=0.03). Within the entire cohort, HbA1c was positively associated with MAT (p≤0.03), and age was associated with higher MAT and lower MAT unsaturation (p≤0.05). Lumbar spine vBMD was inversely associated with lumbar spine MAT (p=0.04). There was an inverse association between SAT and diaphyseal MAT (p<0.05) while there were no associations with VAT. Subjects with morbid obesity and T2DM have higher MAT with a lower proportion of unsaturated lipids, despite higher femoral neck vBMD. MAT is positively associated with age and HbA1c, and inversely associated with vBMD, suggesting that MAT may serve as an imaging biomarker of skeletal health and metabolic risk.

Effects of Roux-en-Y gastric bypass and sleeve gastrectomy on bone mineral density and marrow adipose tissue

Bariatric surgery is associated with bone loss but skeletal consequences may differ between Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), the two most commonly performed bariatric procedures. Furthermore, severe weight loss is associated with high marrow adipose tissue (MAT); however, MAT is also increased in visceral adiposity. The purpose of our study was to determine the effects of RYGB and SG on BMD and MAT. We hypothesized that both bariatric procedures would lead to a decrease in BMD and MAT. We studied 21 adults with morbid obesity (mean BMI 44.1±5.1kg/m²) prior to and 12months after RYGB (n=11) and SG (n=10). All subjects underwent DXA and QCT of the lumbar spine and hip to assess aBMD and vBMD. Visceral (VAT) and subcutaneous (SAT) adipose tissue was quantified at L1-L2. MAT of the lumbar spine and femur was assessed by 1H-MR spectroscopy. Calcitropic hormones and bone turnover markers were determined. At 12months after surgery, mean weight and abdominal fat loss was similar between the RYGB and SG groups. Mean serum calcium, 25(OH)-vitamin D, and PTH levels were unchanged after surgery and within the normal range in both groups. Bone turnover markers P1NP and CTX increased within both groups and P1NP increased to a greater extent in the RYGB group (p=0.03). There were significant declines from baseline in spine aBMD and vBMD within the RYGB and SG groups, although the changes were not significantly different between groups (p=0.3). Total hip and femoral neck aBMD by DXA decreased to a greater extent in the RYGB than the SG group (p<0.04) although the change in femoral vBMD by QCT was not significantly different between groups (p>0.2). MAT content of the lumbar spine and femoral diaphysis did not change from baseline in the RYGB group but increased after SG (p=0.03). Within the SG group, 12-month change in weight and VAT were positively associated with 12-month change in MAT (p<0.04), suggesting that subjects with less weight and VAT loss had higher MAT. In conclusion, RYGB and SG are associated with declines in lumbar spine BMD, however, the changes are not significantly different between the groups. RYGB may be associated with greater decline of aBMD at the total hip and femoral neck compared to SG. MAT content increased after SG and this was associated with lower weight and VAT loss.

Morphological, densitometric and mechanical properties of mandible in 5-month-old Polish Merino sheep

BACKGROUND

Among bones building the axial and appendicular skeleton, the mandible is characterized by unique morphological and functional traits. The aim of the study was to evaluate morphological, densitometric and mechanical properties of mandible in 5-month-old Polish Merino sheep. Using quantitative computed tomography, volumetric bone mineral density (vBMD) and calcium hydroxyapatite density of the cortical bone (CbCa-HA), mean vBMD (MvBMD) and total bone volume were determined. Using computed tomography cross-sectional scans of the mandible, cross-sectional area, second moment of inertia, mean relative wall thickness and cortical index were determined. Three-point bending test was applied to determine mechanical properties. Serum concentration of insulin-like growth factor I (IGF-I) and bone-specific alkaline phosphatase (BAP) was also measured.

RESULTS

All the investigated morphometric, densitometric and mechanical parameters of the right and left mandibular halves were not significantly different (P > 0.05). There was no correlation of final body weight, MvBMD, CbCa-HA, BAP and IGF-I with all the analyzed parameters of mandible (P > 0.05). However, positive correlations between the other investigated morphometric, densitometric and mechanical parameter of mandible were found (P < 0.05).

CONCLUSIONS

Relationships between morphological, densitometric and mechanical parameters of the mandible indicate that the elaborated experimental model may serve for further studies on metabolic responses of skeletal system to physiological, nutritional, pharmacological, toxicological and environmental factors.

Analyzing bone remodeling patterns after total hip arthroplasty using quantitative computed tomography and patient-specific 3D computational models

BACKGROUND

Computational models in the form of finite element analysis technique that incorporates bone remodeling theories along with DEXA scans has been extensively used in predicting bone remodeling patterns around the implant. However, majority of such studies used generic models. Therefore, the aim of this study is to develop patient-specific finite element models of total hip replacement patients using their quantitative computed tomography (QCT) scans and accurately analyse bone remodelling patterns after total hip arthroplasty (THA).

METHODS

Patient-specific finite element models have been generated using the patients' QCT scans from a previous clinical follow-up study. The femur was divided into five regions in proximal-distal direction and then further divided into four quadrants for detailed analysis of bone remodeling patterns. Two types of analysis were performed-inter-patient and intra patient to compare them and then the resulting bone remodeling patterns were quantitatively analyzed.

RESULTS

Our results show that cortical bone density decrease is higher in diaphyseal region over time and the cancellous bone density decreases significantly in metaphyseal region over time. In metaphyseal region, posterior-medial (P-M) quadrant showed high bone loss while diaphyseal regions show high bone loss in anterior-lateral (A-L) quadrant.

CONCLUSIONS

Our study demonstrated that combining QCT with 3D patient-specific models has the ability of monitoring bone density change patterns after THA in much finer details. Future studies include using these findings for the development of a bone remodelling algorithm capable of predicting surgical outcomes for THA patients.

Clinical Use of Quantitative Computed Tomography (QCT) of the Hip in the Management of Osteoporosis in Adults: the 2015 ISCD Official Positions-Part I

The International Society for Clinical Densitometry (ISCD) has developed new official positions for the clinical use of quantitative computed tomography of the hip. The ISCD task force for quantitative computed tomography reviewed the evidence for clinical applications and presented a report with recommendations at the 2015 ISCD Position Development Conference. Here, we discuss the agreed on ISCD official positions with supporting medical evidence, rationale, controversy, and suggestions for further study. Parts II and III address the advanced techniques of finite element analysis applied to computed tomography scans and the clinical feasibility of existing techniques for opportunistic screening of osteoporosis using computed tomography scans obtained for other diagnosis such as colonography was addressed.