Age and BMI have different effects on subcutaneous, visceral, liver, bone marrow, and muscle adiposity, as measured by CT and MRI.

OBJECTIVE: We analyzed quantitative computed tomography (CT) and chemical shift-encoded magnetic resonance imaging (MRI) data from a Chinese cohort to investigate the effects of BMI and aging on different adipose tissue (AT) depots. METHODS: In 400 healthy, community-dwelling individuals aged 22 to 83 years, we used MRI to quantify proton density fat fraction (PDFF) of the lumbar spine (L2-L4) bone marrow AT (BMAT), the psoas major and erector spinae (ES) muscles, and the liver. Abdominal total AT, visceral AT (VAT), and subcutaneous AT (SAT) areas were measured at the L2-L3 level using quantitative CT. Partial correlation analysis was used to evaluate the relationship of each AT variable with age and BMI. Multiple linear regression analysis was performed in which each AT variable was evaluated in turn as a function of age and the other five independent AT measurements. RESULTS: Of the 168 men, 29% had normal BMI (<24.0 kg/m2), 47% had overweight (24.0-27.9 kg/m2), and 24% had obesity (≥ 28.0 kg/m2). In the 232 women, the percentages were 46%, 32%, and 22%, respectively. Strong or very strong correlations with BMI were found for total AT, VAT, and SAT in both sexes. BMAT and ES PDFF was strongly correlated with age in women and moderately correlated in men. In both sexes, BMAT PDFF correlated only with age and not with any of the other AT depots. Psoas PDFF correlated only with ES PDFF and not with age or the other AT depots. Liver PDFF correlated with BMI and VAT and weakly with SAT in men. VAT and SAT correlated with age and each other in both sexes. CONCLUSIONS: Age and BMI are both associated with adiposity, but their effects differ depending on the type of AT.

Risk prediction of second hip fracture by bone and muscle density of the hip varies with time after first hip fracture: A prospective cohort study.

Purpose: Predictors of 'imminent' risk of second hip fracture are unknown. The aims of the study were to explore strength of hip areal bone mineral density (aBMD), and muscle area and density for predicting second hip fracture at different time intervals. Methods: Data of the Chinese Second Hip Fracture Evaluation were analyzed, a longitudinal study to evaluate the risk of second hip fracture (of the contralateral hip) by using CT images obtained immediately after first hip fracture. Muscle cross-sectional area and density were measured of the gluteus maximus (G.MaxM) and gluteus medius and minimus (G.Med/MinM) and aBMD of the proximal femur at the contralateral unfractured side. Patients were followed up for a median time of 4.5 years. Separate Cox models were used to predict second hip fracture risk at different time intervals after first event adjusted for age, sex, BMI and diabetes. Results: The mean age of subjects with imminent (within 1st or 2nd year) second hip fracture was 79.80 ± 5.16 and 81.56 ± 3.64 years. In the 1st year after the first hip fracture, femoral neck (FN) aBMD predicted second hip fracture (HR 5.88; 95 % CI, 1.32-26.09). In the remaining years of follow-up after 2nd year, muscle density predicted second hip fracture (G.MaxM HR 2.13; 95 % CI, 1.25-3.65,G.Med/MinM HR 2.10; 95 % CI, 1.32-3.34). Conclusions: Our results show that femoral neck aBMD is an important predictor for second hip fracture within the first year and therefore suggest supports the importance concept of early and rapid-acting bone-active drugs to increase hip BMD. In addition, the importance of muscle density predicting second hip fracture after the second year suggest post hip fracture rehabilitation and exercise programs could also be important to reduce muscle fatty infiltration.

Deep Learning-Based Fully Automated Segmentation of Regional Muscle Volume and Spatial Intermuscular Fat Using CT.

RATIONALE AND OBJECTIVES: We aim to develop a CT-based deep learning (DL) system for fully automatic segmentation of regional muscle volume and measurement of the spatial intermuscular fat distribution of the gluteus maximus muscle. MATERIALS AND METHODS: A total of 472 subjects were enrolled and randomly assigned to one of three groups: a training set, test set 1, and test set 2. For each subject in the training set and test set 1, we selected six slices of the CT images as the region of interest for manual segmentation by a radiologist. For each subject in test set 2, we selected all slices of the gluteus maximus muscle on the CT images for manual segmentation. The DL system was constructed using Attention U-Net and the Otsu binary thresholding method to segment the muscle and measure the fat fraction of the gluteus maximus muscle. The segmentation results of the DL system were evaluated using the Dice similarity coefficient (DSC), Hausdorff distance (HD), and the average surface distance (ASD) as metrics. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to assess agreement in the measurements of fat fraction between the radiologist and the DL system. RESULTS: The DL system showed good segmentation performance on the two test sets, with DSCs of 0.930 and 0.873, respectively. The fat fraction of the gluteus maximus muscle measured by the DL system was in agreement with the radiologist (ICC=0.748). CONCLUSION: The proposed DL system showed accurate, fully automated segmentation performance and good agreement with the radiologist at fat fraction evaluation, and can be further used for muscle evaluation.

Muscle size and density are independently associated with death after hip fracture: A prospective cohort study.

BACKGROUND: Mortality following hip fracture is high and incompletely understood. We hypothesize that hip musculature size and quality are related to mortality following hip fracture. This study aims to investigate the associations of hip muscle area and density from hip CT with death following hip fracture as well as assess the dependence of this association on time after hip fracture. METHODS: In this secondary analysis of the prospectively collected CT images and data from the Chinese Second Hip Fracture Evaluation, 459 patients were enrolled between May 2015 and June 2016 and followed up for a median of 4.5 years. Muscle cross-sectional area and density were measured of the gluteus maximus (G.MaxM) and gluteus medius and minimus (G.Med/MinM) and aBMD of the proximal femur. The Goutallier classification (GC) was used for qualitatively assessing muscle fat infiltration. Separate Cox models were used to predict mortality risk adjusted for covariates. RESULTS: At the end of the follow-up, 85 patients were lost, 81 patients (64% women) had died, and 293 (71% women) survived. The mean age of non-surviving patients at death (82.0 ± 8.1 years) was higher than that of the surviving patients (74.4 ± 9.9 years). The Parker Mobility Score and the American Society of Anesthesiologists scores of the patients that died were respectively lower and higher compared to the surviving patients. Hip fracture patients received different surgical procedures, and no significant difference in the percentage of hip arthroplasty was observed between the dead and the surviving patients (P = 0.11). The cumulative survival was significantly lower for patients with low G.MaxM area and density and low G.Med/MinM density, independent of age and clinical risk scores. The GC grades were not associated with the mortality after hip fracture. Muscle density of both G.MaxM (adj. HR 1.83; 95% CI, 1.06-3.17) and G.Med/MinM (adj. HR 1.98; 95% CI, 1.14-3.46) was associated with mortality in the 1st year after hip fracture. G.MaxM area (adj. HR 2.11; 95% CI, 1.08-4.14) was associated with mortality in the 2nd and later years after hip fracture. CONCLUSION: Our results for the first time show that hip muscle size and density are associated with mortality in older hip fracture patients, independent of age and clinical risk scores. This is an important finding to better understand the factors contributing to the high mortality in older hip fracture patients and to develop better future risk prediction scores that include muscle parameters.

Greater bone marrow fat and myosteatosis are associated with lower vBMD but not asymptomatic vertebral fracture.

OBJECTIVES: Organ fat may affect bone metabolism and be associated with vertebral fracture (VF). This study aimed to explore relationships between VF, adiposity indexes measured by MRI, and volumetric BMD (vBMD) measured by quantitative CT (QCT). METHODS: Four hundred volunteers, ranging in age from 22 to 83 years, were recruited and underwent same-day abdominal QCT and chemical shift-encoded (CSE) MRI. We used MRI to quantify the fat content of bone marrow (BMF), psoas major and paraspinal muscles, and the liver. Abdominal fat, VF, and vBMD of the lumbar spine were measured by QCT. For VF discrimination analysis, we examined both the whole cohort (60 VF cases in 30 men and 30 women) and a restricted subgroup of those aged over 50 years (50 VF cases in 23 men and 27 women). RESULTS: Amongst the men, a 1 SD increase in BMF was associated with a 27.67 (95% CI, -32.71 to -22.62) mg/cm3 decrease in vBMD after adjusting for age and BMI. Amongst women, all adiposity indexes except for liver fat were significantly associated with vBMD, with BMF having the strongest association (ß, -24.00; 95% CI, -28.54 to -19.46 mg/cm3). Similar findings were also observed in participants aged over 50 years. The associations of adiposity indexes with vertebral fracture were not significant after adjusting for age in both sexes aged over 50 years. CONCLUSIONS: In both sexes, higher bone marrow fat was associated with lower vBMD at the spine. However, marrow fat and other adipose tissues were not associated with radiographic-based prevalent vertebral fractures. KEY POINTS: • In both sexes, higher bone marrow fat was associated with lower vBMD at the spine. • Among women, all adiposity indexes except for liver fat content were significantly associated with vBMD, with bone marrow fat having the strongest association. • Marrow fat and other adipose tissues were not associated with radiographic-based asymptomatic vertebral fractures.

Muscle density is an independent risk factor of second hip fracture: a prospective cohort study.

BACKGROUND: Patients with a first hip fracture are at high risk of fracturing their other hip. Despite this, preventive therapy is often not given. Because little is known about specific risk factors of a second hip fracture, we investigated the association with areal bone mineral density (aBMD), muscle size, and density. We also investigated whether muscle parameters predict the risk of a contralateral fracture independently of aBMD. METHODS: Three groups were included, one without hip fracture (a subcohort of the China Action on Spine and Hip Status study), one with a first, and one with a second hip fracture. Subjects with fractures were recruited from the longitudinal Chinese Second Hip Fracture Evaluation (CSHFE). Computed tomography scans of CSHFE patients, which were obtained immediately following their first fracture, were used to measure cross-sectional area and density of the gluteus maximus (G.MaxM) and gluteus medius and minimus (G.Med/MinM) muscles. Computed tomography X-ray absorptiometry was used to measure aBMD of the contralateral femur. Median follow-up time to second fracture was 4.5 years. Cox proportional hazards models were used to compute hazard ratios (HR) of second hip fracture risk in subjects with a first hip fracture. Multivariate logistic regressions were used to compare odds ratios (OR) for the risk of a first and second hip fracture. RESULTS: Three hundred and one participants (68.4 ± 6.1 years, 64% female) without and 302 participants (74.6 ± 9.9 years, 71% female) with a first hip fracture were included in the analysis. Among the latter, 45 (79.2 ± 7.1 years) sustained a second hip fracture. ORs for first hip fracture were significant for aBMD and muscle size and density. ORs for a second fracture were smaller by a factor of 3 to 4 and no longer significant for femoral neck (FN) aBMD. HRs for predicting second hip fracture confirmed the results. G.Med/MinM density (HR, 1.68; CI, 1.20-2.35) and intertrochanter aBMD (HR, 1.62; CI, 1.13-2.31) were the most significant. FN aBMD was not significant. G.Med/MinM density remained significant for predicting second hip fracture after adjustment for FN (HR, 1.66; Cl, 1.18-2.30) or total hip aBMD (HR, 1.50; 95% Cl, 1.04-2.15). CONCLUSIONS: Density of the G.Med/MinM muscle is an aBMD independent predictor of the risk of second hip fracture. Intertrochanteric aBMD is a better predictor of second hip fracture than FN and total hip aBMD. These results may trigger a paradigm shift in the assessment of second hip fracture risk and prevention strategies.

Differences in Hip Geometry Between Female Subjects With and Without Acute Hip Fracture: A Cross-Sectional Case-Control Study.

Background and Purpose: Although it is widely recognized that hip BMD is reduced in patients with hip fracture, the differences in geometrical parameters such as cortical volume and thickness between subjects with and without hip fracture are less well known. Materials and Methods: Five hundred and sixty two community-dwelling elderly women with hip CT scans were included in this cross-sectional study, of whom 236 had an acute hip fracture. 326 age matched women without hip fracture served as controls. MIAF-Femur software was used for the measurement of the intact contralateral femur in patients with hip fracture and the left femur of the controls. Integral and cortical volumes (Vols) of the total hip (TH), femoral head (FH), femoral neck (FN), trochanter (TR) and intertrochanter (IT) were analyzed. In the FH and FN the volumes were further subdivided into superior anterior (SA) and posterior (SP) as well as inferior anterior (IA) and posterior (IP) quadrants. Cortical thickness (CortThick) was determined for all sub volumes of interest (VOIs) listed above. Results: The average age of the control and fracture groups was 71.7 and 72.0 years, respectively. The fracture patients had significantly lower CortThick and Vol of all VOIs except for TRVol. In the fracture patients, cortical thickness and volume at the FN were significantly lower in all quadrants except for cortical volume of quadrant SA (p= 0.635). Hip fracture patients had smaller integral FN volume and cross-sectional area (CSA) before and after adjustment of age, height and weight. With respect to hip fracture discrimination, cortical volume performed poorer than cortical thickness across the whole proximal femur. The ratio of Cort/TrabMass (RCTM), a measure of the internal distribution of bone, performed better than cortical thickness in discriminating hip fracture risk. The highest area under curve (AUC) value of 0.805 was obtained for the model that included THCortThick, FHVol, THRCTM and FNCSA. Conclusion: There were substantial differences in total and cortical volume as well as cortical thickness between fractured and unfractured women across the proximal femur. A combination of geometric variables resulted in similar discrimination power for hip fracture risk as aBMD.

Dedifferentiated Central Chondrosarcoma: A Clinical, Histopathological, and Immunohistochemical Analysis of 57 Cases.

Dedifferentiated central chondrosarcoma (DCCS) is a rare cartilage tumor with invasive biological behavior and a poor prognosis. To better understand the morphological characteristics of this type of tumor and its internal mechanism of dedifferentiation, we retrospectively analyzed 57 cases of DCCS. A total of 29 female and 28 male patients were included, ranging in age from 20 to 76 years, with a median age of 54 years. Fifty-seven cases of DCCS occurred in the pelvis (n = 29), femur (n = 17), scapula (n = 4), tibia (n = 2), humerus (n = 2), metatarsals (n = 1), fibula (n = 1), and radius (n = 1). Radiologically, DCCS had two different appearances on imaging, with an area showing calcifications of the cartilage forming the tumor juxtaposed to a lytic area with a highly aggressive, non-cartilaginous component. Histopathologically, the distinctive morphological features consisted of two kinds of defined components: a well-differentiated cartilaginous tumor and non-cartilaginous sarcoma. The cartilaginous components included grade 1 (n = 38; 66.7%) and grade 2 (n = 19; 33.3%) cartilage. The sarcoma components included those of osteosarcoma (n = 29; 50.9%), undifferentiated pleomorphic sarcoma (n = 20; 35.1%), rhabdomyosarcoma (n = 3; 5.2%), fibrosarcoma (n = 2; 3.5%), spindle cell sarcoma (n = 2; 3.5%) and angiosarcoma (n = 1; 1.8%). Immunohistochemistry showed that the expression of p53 and RB in the sarcoma components was significantly higher than that in the cartilaginous components, suggesting that these factors play roles in the dedifferentiation process of chondrosarcoma. DCCS is a highly malignant tumor with a poor prognosis. Except for the patients who were lost to follow-up, most of our patients died.

Muscle Density, but Not Size, Correlates Well With Muscle Strength and Physical Performance.

OBJECTIVES: There is increasing evidence that muscle volume and mass are poor predictors of muscle strength and physical performance. Other assessments of muscle quality such as skeletal muscle density measured by computed tomography (CT) may be more important. The aim of this study was to explore associations of muscle size and density with handgrip strength (HGS) and the Timed Up and Go test (TUG). We also hypothesized that the strength of these associations would depend on the specific muscle of muscle group, namely trunk, hip, and mid-thigh muscles. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: University hospital; 316 volunteers aged 59 to 85 years. METHODS: HGS, TUG, and quantitative CT imaging of the lumber, hip, and mid-thigh were performed in volunteers. From the CT images, cross-sectional area and attenuation were determined for the gluteus muscle, trunk muscle at vertebrae L2 level, and mid-thigh muscle. RESULTS: In men and women, associations of muscle area with TUG were insignificant after adjustment for age, height, and weight. Associations with HGS were only significant in men for the gluteus maximus and the mid-thigh but slopes were rather low (ß < 0.20). Associations between muscle density and TUG/HGS were more pronounced, in particular for HGS. After adjustment, associations with TUG were significant in women for the gluteus maximus and trunk muscle even (ß -0.06, P .001 and ß -0.07, P .031, respectively). CONCLUSIONS AND IMPLICATIONS: Muscle density is more strongly associated with muscle strength than muscle size andin women muscle density was also more strongly associated than muscle size with physical performance. Therefore, muscle density may represent a more clinically meaningful surrogate of muscle performance than muscle size. Muscle density measurements of trunk and gluteus muscles can be easily obtained from routine CT scan and, therefore, may become an important measurement to diagnose and screen for sarcopenia.

High-Grade Surface Osteosarcoma: Clinical Features and Oncologic Outcome.

BACKGROUND: High-grade surface osteosarcoma is an extremely rare subtype of osteosarcoma. The treatment outcome for this tumor varies in different centers. METHODS: This was a retrospective study of high-grade surface osteosarcoma; clinical, radiological, and histological materials were reviewed. RESULTS: We studied 23 patients (16 males, seven females); median age was 24 years old. All the tumors involved the lower limb, located at the diaphysis in 11 patients and at the metaphysis in 12 patients. Even though the majority of tumors were located at the surface of the bone, the medullary canal was involved in 10 patients. The microscopic findings were indistinguishable from conventional central osteosarcoma. All the patients were treated with a combination of surgery and systemic chemotherapy. Follow-up data were completed in 20 patients; follow-up duration ranged from 27 months to 182 months or until the patient died of the disease (5-104 months). Of the 20 patients, 12 died of the disease, and eight patients were alive at the time of the last follow-up. The 5-year overall survival rate was 37.6%. CONCLUSIONS: Our study revealed that the treatment outcome for this tumor shows a poor survival rate.

Muscle density discriminates hip fracture better than computed tomography X-ray absorptiometry hip areal bone mineral density.

BACKGROUND: Muscle weakness is a key factor in the increase risk of falls and might also play a significant role in the increase of risk of hip fracture. Computed tomography-measured muscle size and muscle density are well-established imaging biomarkers used in studies of physical function, frailty or cancer, but limited to hip fracture. In particular, it is warranted to have a better understanding of the performance of muscle size and density in the discrimination of acute hip fractures. We also aim to determine age-related differences of muscle size and density in healthy controls and hip fracture patients. METHODS: Four hundred thirty-eight low-energy acute hip fracture cases and 316 healthy controls from the China Action on Spine and Hip Status study were included in the study. Muscle cross-sectional area and density were measured for the gluteus maximus and gluteus medius and minimus. Areal bone mineral density (aBMD) of the femoral neck and total hip was measured. Using propensity score matching, we generated three samples with cases and controls matched for age, body mass index, and gender: femoral neck fracture (FNF), intertrochanteric fracture (ITF), and any hip fracture vs. controls, respectively. RESULTS: Handgrip strength, gluteus muscle area and density, and bone parameters of the matched hip fracture groups were lower than those of the correspondence control groups, respectively (P < 0.05). The univariate analysis showed that associations of aBMD with FNF and with ITF were significantly weaker than associations between fracture and muscle parameters. Gluteus medius and minimus muscle density showed the highest areas under the curve (AUC) with FNF (0.88, 95% confidence interval, 0.85-0.92) and trochanteric fracture (0.95, 95% confidence interval, 0.92-0.97). The model including all muscle and bone parameters provided the highest AUC (FNF: AUC 0.912; ITF: AUC 0.958), and AUC results of another selected model without muscle density showed that association with fracture significantly dropped (FNF: AUC 0.755; ITF: AUC 0.858). Separate results for the two age groups younger and older than 70 years showed no age-related significant differences in discriminate models. CONCLUSIONS: Muscle density performs better than aBMD from hip computed tomography X-ray absorptiometry and muscle size in discrimination of hip fracture. Combination of aBMD and muscle density provided the best discrimination. The integration of muscle assessments may trigger a paradigm shift in hip fracture prediction. Gluteus muscle density should also be evaluated as treatment outcome.

Associations of Muscle Size and Density With Proximal Femur Bone in a Community Dwelling Older Population.

Background and Purpose: Muscle weakness and bone fragility are both associated with hip fracture. In general, muscle contractions create forces to the bone, and bone strength adapts to mechanical loading through changes in bone architecture and mass. However, the relationship between impairment of muscle and bone function remain unclear. In particular, the associations of muscle with properties of proximal femur cortical and trabecular bone are still not well understood. The aim of this study was to explore the associations of hip/thigh muscle density (CT attenuation value in Hounsfield units) and size with cortical and trabecular bone mineral density (BMD) of the proximal femur. Materials and Methods: Three-dimensional quantitative computed tomography (QCT) imaging of the lumber, hip and mid-thigh was performed in a total of 301 participants (mean age 68.4 ± 6.1 years, 194 women and 107 men) to derive areal BMD (aBMD) and volumetric BMD (vBMD). Handgrip strength (HGS) and the Timed Up and Go (TUG) test were also performed. From the CT images, cross-sectional area (CSA), and density were determined for the gluteus maximus muscle (G.MaxM), trunk muscle at the vertebrae L2 level, and mid-thigh muscle. Multivariate generalized linear models were applied to assess associations. Results: Total hip (TH) aBMD was associated significantly with G.MaxM CSA (men: P = 0.042; women: P < 0.001) and density (men: P = 0.012; women: P = 0.043). In women, 0.035 cm2 of mid-thigh CSA (95% CI, 0.014-0.057; P = 0.002) increased per SD increase in TH aBMD, but this significance was not observed in men (P = 0.095). Trunk muscle density and CSA were not associated with proximal femur BMD. The associations of hip/thigh muscle parameters with femoral neck BMD were weaker than those with trochanter and intertrochanter BMD. Furthermore, compared to muscle density, muscle CSA showed better associations with vBMD. G.MaxM CSA was associated with trochanter (TR) Cort. vBMD in men (ß, 19.898; 95% CI, 0.924-38.871; P = 0.040) and in women (ß, 15.426; 95% CI, 0.893-29.958; P = 0.038). Handgrip strength was only associated with TR aBMD (ß, 0.038; 95% CI, 0.006-0.070; P = 0.019) and intertrochanter aBMD (ß, 0.049; 95% CI, 0.009-0.090; P = 0.016) in men. Conclusions: We observed positive associations of the gluteus and thigh muscle size with proximal femur volumetric BMD. Specifically, the gluteus maximus muscle CSA was associated with trochanter cortical vBMD in both men and women.

Lack of periosteal apposition in the head and neck of femur after menopause in Chinese women with high risk for hip fractures - A cross-sectional study with QCT.

In elderly subjects and in particular in those with osteoporosis the evidence on age related volume changes of the hip is still very limited. Even less is known about bone changes of the femoral head. The aim of this study is to explore associations of bone size of the femoral head and neck with age in postmenopausal women with very high risk of hip fracture and to investigate associations of femoral head and neck bone mineral density. MIAF (medical image analysis framework)-Femur was used for the analysis of CT datasets from 319 females with acute hip fractures age 50 to 98. Integral BMD and volume of the head and neck were assessed. The femoral head was divided into four quadrants to address differential vBMD and volume responses of its superior, inferior, posterior and anterior parts. Areal BMD (aBMD) of femoral neck was also obtained. In this population of postmenopausal women we did not observe age-related changes in bone volume of the femoral head or neck between ages 50 and 98 years. Integral vBMD in the head in the 90-98 year group was 48.0 mg/cm3 lower than that in 50-59 year group, which accounts for nearly 30% decrease in vBMD with 40 years increase. Age-related vBMD changes in the head quadrants were similar to that in total. With age, the trend line correlation coefficients for vBMD in quadrants were relatively small, but significant (p < 0.001) for all. The femoral head integral vBMD correlates well with neck vBMD and FN aBMD. FN aBMD explained 45% of head integral vBMD variance (p < 0.0001). Elderly women had relative preservation of femoral head and neck bone volume from 50 yrs. over four decades but markedly lower integral vBMD of proximal femur. The findings of our study call in question about the concept of bone expansion with aging even in elderly age.

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.

The spatial differences in bone mineral density and hip structure between low-energy femoral neck and trochanteric fractures in elderly Chinese using quantitative computed tomography.

The purpose of this study was to investigate the differences in bone mineral density (BMD) and hip structure between femoral neck and trochanteric fractures in elderly Chinese individuals using quantitative computed tomography (QCT). A total of 625 Chinese patients (mean age 75.8 years) who sustained low-energy hip fractures (female: 293 femoral neck, 175 trochanteric; male: 82 femoral neck, 75 trochanteric) were recruited. Each patient underwent a hip QCT scan. The areal BMD (aBMD) of the contralateral normal hip was obtained using a computed tomography X-ray absorptiometry module. Using the bone investigation toolkit (BIT) module, the femoral neck was divided into four quadrants: supero-anterior (SA), infero-anterior (IA), infero-posterior (IP), and supero-posterior (SP). Estimated cortical thickness, cortical BMD, and trabecular BMD were measured in each quadrant. Using the hip structure analysis (HSA) function, several parameters were calculated. Stratified by sex, covariance analyses were applied to compare the femoral neck fractures group with trochanteric fractures group after adjustments for age, height, and weight. In women, trochanteric fractures exhibited lower trabecular BMD and estimated cortical thickness at three quadrants of the femoral neck (IA: P = 0.02, P < 0.01; IP: P < 0.01, P = 0.01; SP: P = 0.01, P < 0.01), and lower aBMD at the trochanter area (P < 0.01); femoral neck fractures exhibited lower cortical BMD and estimated cortical thickness at the SA quadrant (P = 0.04, P = 0.01). Differences in HSA parameters were not statistically significant. Among all parameters, the most valuable ones to discrimination of hip fracture type are estimated cortical thickness of the SA quadrant of femoral neck and the aBMD of the trochanter area. In men, only lower cortical BMD at the SP quadrant and aBMD at the trochanter were found in the trochanteric fractures (P = 0.02, P < 0.01). QCT outcomes indicate that spatial differences are helpful to explore the pathogenesis of different type of hip fractures. In women, trochanteric fractures are related to severer osteoporosis, whereas cortical fragility in the SA region of the femoral neck predominates in cases of femoral neck fractures. In men, trochanteric fractures are related to more bone loss of trochanter.

QCT of the femur: Comparison between QCTPro CTXA and MIAF Femur.

QCT is commonly employed in research studies and clinical trials to measure BMD at the proximal femur. In this study we compared two analysis software options, QCTPro CTXA and MIAF-Femur, using CT scans of the semi-anthropometric European Proximal Femur Phantom (EPFP) and in vivo data from 130 Chinese elderly men and women aged 60-80 years. Integral (Int), cortical (Cort) and trabecular (Trab) vBMD, volume, and BMC of the neck (FN), trochanter (TR), inter-trochanter (IT), and total hip (TH) VOIs were compared. Accuracy was determined in the 5 mm wide central portion of the femoral neck of the EPFP. Nominal values were: cross-sectional area (CSA) 4.9 cm2, cortical thickness (C.Th) 2 mm, CortBMD 723 mg/cm3 and TrabBMD 100 mg/cm3. In MIAF the so-called peeled trabecular VOI was analyzed, which excludes subcortical bone to avoid partial volume artefacts at the endocortical border that artificially increase TrabBMD. For CTXA uncorrected, so called raw cortical values were used for the analysis. QCTPro and MIAF phantom results were: CSA 5.9 cm2 versus 5.1 cm2; C.Th 1.68 mm versus 1.92 mm; CortBMD 578 mg/cm3 versus 569 mg/cm3; and TrabBMD 154 mg/cm3 versus 104 mg/cm3. In vivo correlations (R2) of integral and trabecular bone parameters ranged from 0.63 to 0.96. Bland-Altman analysis for TH and FN TrabBMD showed that lower mean values were associated with higher differences, which means that TrabBMD differences between MIAF and CTXA are larger for osteoporotic than for normal patients, which can be largely explained by the inclusion of subcortical BMD in the trabecular VOI analyzed by CTXA in combination with fixed thresholds used to separate cortical from trabecular bone compartments. Correlations between CTXA corrected CortBMD and MIAF were negative, whereas raw data correlated positively with MIAF measurements for all VOIs questioning the validity of the CTXA corrections. The EPFP results demonstrated higher MIAF accuracy of cortical thickness and TrabBMD. Integral and trabecular bone parameters were highly correlated between CTXA and MIAF. Partial volume artefacts at the endocortical border artificially increased trabecular BMD by CTXA, especially for osteoporosis patients. With respect to volumetric cortical measurements with CTXA, the use raw data is recommended, because corrected data cause a negative correlation with MIAF CortBMD.

Marrow signal mimicking tumor on MRI T1-weighted imaging after neoadjuvant chemotherapy in extremity osteosarcomas.

PURPOSE: Many studies had demonstrated that MRI T1-weighted imaging was the most accurate method to evaluate the intramedullary extent of extremity osteosarcoma. However, we found that after neoadjuvant chemotherapy new low signal of MRI T1 imaging was detected near tumor, which mimicked the tumor progression. The aim of this study was to describe the incidence and type of this new signal, to reveal the pathological correlation with this imaging change. METHODS: We included 74 extremity osteosarcomas managed between June 2011 and November 2012 in this retrospective study. The T1-weighted MRI images of the affected extremity before and after neoadjuvant chemotherapy were reviewed and compared. The subjects were then classified according to the appearance of the border between the area involved by osteosarcoma and the normal marrow with attention paid to whether the border was continuous and the width of the zone of transition. The study population was classified into one of four classifications: 'clear', 'continuous diffuse', 'discontinuous island-like' and 'discontinuous diffuse'. 11 patients underwent MRI of bilateral extremities, and for these patients we assessed the appearance of the uninvolved extremity with that with osteosarcoma. Following surgical resection of the tumor, the pathologic appearance was compared with the pre-operative MRI findings. RESULTS: According to our classification system, all 74 subjects were 'clear' before neoadjuvant chemotherapy. After neoadjuvant chemotherapy, 30 subjects (40.5%) were still clear. Of the 44 subjects (59.5%) not classified as 'clear', 22 (29.7%) were classified as 'continuous diffuse', 4 (5.4%) as 'discontinuous island-like', and 18 (24.3%) as 'discontinuous diffuse'. Of the subjects with MRI of bilateral femurs, no radiologic difference was noted in the normal marrow bilaterally. No significant difference in overall survival and relapse free survival was noted between patients grouped according to the subtypes of MRI noted. CONCLUSIONS: Neoadjuvant chemotherapy for extremity osteosarcoma can result in a variety of changes of the MRI appearance of tumor and adjacent bone and marrow. Areas of signal change beyond the tumor that represent marrow conversion and not tumor progression appear on T1 weighted imaging to be lower in signal than subcutaneous fat and higher in signal than muscle. Recognizing the existence of the effect of neoadjuvant chemotherapy on the MR appearance of the tumor and surrounding bone and myeloid elements is important so as to plan for oncological sound tumor resections while avoiding resecting more normal bone than necessary.

Validation of asynchronous quantitative bone densitometry of the spine: Accuracy, short-term reproducibility, and a comparison with conventional quantitative computed tomography.

Asynchronous calibration quantitative computed tomography (QCT) is a new tool that allows the quantification of bone mineral density (BMD) without the use of a calibration phantom during scanning; however, this tool is not fully validated for clinical use. We used the European spine phantom (ESP) with repositioning during scanning and assessed the accuracy and short-term reproducibility of asynchronous QCT. Intra-scanner and intra-observer precision were each calculated as the root mean square of the standard deviation (RMSSD) and the coefficient of variation (CV-RMSSD). We also compared asynchronous and conventional QCT results in 50 clinical subjects. The accuracy of asynchronous QCT for three ESP vertebrae ranged from 1.4-6.7%, whereas intra-scanner precision for these vertebrae ranged from 0.53-0.91 mg/cc. Asynchronous QCT was most precise for a trabecular BMD of 100 mg/cc (CV-RMSSD = 0.2%). For intra-observer variability, overall precision error was smaller than 3%. In clinical subjects there was excellent agreement between the two calibration methods with correlation coefficients ranging from 0.96-0.99. A Bland-Altman analysis demonstrated that methodological differences depended on the magnitude of the BMD variable. Our findings indicate that the asynchronous QCT has good accuracy and precision for assessing trabecular BMD in the spine.

Spatial Differences in the Distribution of Bone Between Femoral Neck and Trochanteric Fractures.

There is little knowledge about the spatial distribution differences in volumetric bone mineral density and cortical bone structure at the proximal femur between femoral neck fractures and trochanteric fractures. In this case-control study, a total of 93 women with fragility hip fractures, 72 with femoral neck fractures (mean ± SD age: 70.6 ± 12.7 years) and 21 with trochanteric fractures (75.6 ± 9.3 years), and 50 control subjects (63.7 ± 7.0 years) were included for the comparisons. Differences in the spatial distributions of volumetric bone mineral density, cortical bone thickness, cortical volumetric bone mineral density, and volumetric bone mineral density in a layer adjacent to the endosteal surface were investigated using voxel-based morphometry (VBM) and surface-based statistical parametric mapping (SPM). We compared these spatial distributions between controls and both types of fracture, and between the two types of fracture. Using VBM, we found spatially heterogeneous volumetric bone mineral density differences between control subjects and subjects with hip fracture that varied by fracture type. Interestingly, femoral neck fracture subjects, but not subjects with trochanteric fracture, showed significantly lower volumetric bone mineral density in the superior aspect of the femoral neck compared with controls. Using surface-based SPM, we found that compared with controls, both fracture types showed thinner cortices in regions in agreement with the type of fracture. Most outcomes of cortical and endocortical volumetric bone mineral density comparisons were consistent with VBM results. Our results suggest: 1) that the spatial distribution of trabecular volumetric bone mineral density might play a significant role in hip fracture; 2) that focal cortical bone thinning might be more relevant in femoral neck fractures; and 3) that areas of reduced cortical and endocortical volumetric bone mineral density might be more relevant for trochanteric fractures in Chinese women. © 2017 American Society for Bone and Mineral Research.

[Minimally invasive percutaneous plate osteosynthesis for the treatment of acetabulum anterior column fracture with intact true pelvic brim].

OBJECTIVE: To discuss feasibility and clinical effects of minimally invasive percutaneous plate osteosynthesis in treating acetabulum anterior column fracture with intact true pelvic brim. METHODS: From May 2013 to December 2015, 8 patients with acetabulum anterior column fracture with intact true pelvic brim were reviewed retrospectively. According to Judet-Letournel classification, all were simple unstable acetabulum anterior column fracture. Among them, there were 5 males and 3 females with an average age of 42.8 years old ranging from 22 to 63. The injury was caused by crush in 4 cases, smash of heavy object in 3 cases, and falling down in 1 case. The time from injury to operation was ranged from 5 to 19 days with an average of 9.5 days. Preoperative CT showed high anterior column fracture of acetabulum with intact true pelvic brim, the fracture separation was less than 1 cm. All the patients were treated with closed reduction and minimally invasive percutaneous plate osteosynthesis. The quality of fracture reduction, operation time, blood loss, fracture healing time, hip function and postoperative complications were observed and recorded. RESULTS: All patients were followed up from 10 to 19 months with an average of 14.5 months. The quality of reduction was classified as anatomical in 4 patients, imperfect in 3, poor in 1 by Matta's score system. The operation time was 30 to 80 min, averaged 51.3 min;the blood loss was 50 to 120 ml, averaged 86.2 ml; fracture healing time was 10 to 19 weeks, averaged 13.3 weeks. At the latest follow-up, the hip function was evaluated by Merle D'Aubigne scoring system, 5 cases got excellent results, 2 cases in good, and 1 case in fair. No vascular nerve injury, wound infection, bleeding, deep vein thrombosis and other complications occurred in 8 patients. CONCLUSIONS: Minimally invasive percutaneous plate osteosynthesis in treating acetabulum anterior column fracture with intact true pelvic brim has advantages of less trauma, less bleeding, quick recovery and good curative effect, and it is a good surgical procedures for acetabulum anterior column fracture.