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Osteoporosis is related to changes in vertebral bone marrow tissues, which can be detected by MRI. A novel MRI scoring method based on routine T1 and T2 sequences has been developed and demonstrated capabilities in detecting osteoporosis and discriminating vertebral fractures. The scoring method may provide an alternative tool other than BMD measurement for broad, opportunistic use in clinics., Purpose: As a routinely used radiation-free modality at the spine, magnetic resonance imaging (MRI) is promising to assess osteoporosis because it can detect age- or osteoporosis-related changes in bone marrow tissues. Here, we proposed a new MRI scoring method using the patient's low-back subcutaneous fat and cerebrospinal fluid as reference controls on routine T1 and T2 sequences, respectively, to indicate proton-rich changes in vertebrae for assessing osteoporosis and vertebral fractures., Methods: The study included 60 female patients (64.1 ± 15.9 years) who underwent both MRI and quantitative computed tomography (QCT) at spine. T1-based F-score sc.fat and T2-based W-score cs.fluid were defined as the median signal intensity (SI) from L1 to L5 over their reference controls. QCT-measured vertebral BMD was used for defining osteoporosis. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performances of the new scores for osteoporosis and vertebral fractures, which were also compared with L1-L5 signal-to-noise ratio (SNR L1-L5 ) or SNR-based vertebral bone quality (VBQ) score., Results: The F-score sc.fat and W-score cs.fluid increased significantly by 25.3% and 22%, respectively, in patients with osteoporosis compared to non-osteoporosis. Age was also found to be significantly different between non-osteoporosis and osteoporosis (49.92 and 74.03 years, p < .001). ROC analysis indicated that F-score sc.fat had a greater AUC value (0.85, p < .001) than VBQ score (0.77) and SNR L1-L5 (0.71) when being used to detect osteoporosis. For separating vertebral fractures from non-fractures, F-score sc.fat resulted in the largest AUC value of 0.81 (p < .001), compared to W-score cs.fluid (0.74), VBQ (0.72), and SNR L1-L5 (0.75)., Conclusion: A new MRI scoring method based on routine T1 and T2 sequences has been developed and demonstrated improved abilities in detecting osteoporosis and discriminating vertebral fractures over VBQ and SNR., Competing Interests: Declarations. Ethical approval: This research was conducted as per the Declaration of Helsinki and informed consent was taken. Conflicts of interest: None., (© 2025. International Osteoporosis Foundation and Bone Health and Osteoporosis Foundation.)

Vertebral fracture is one of the most serious consequences of osteoporosis. Estimation of vertebral strength from magnetic resonance imaging (MRI) scans may provide a new approach for the prediction of vertebral fractures. To that end, we sought to establish a biomechanical MRI (BMRI) method to compute vertebral strength and test its ability to distinguish fracture from non-fracture subjects. This case-control study included 30 subjects without vertebral fractures and 15 subjects with vertebral fractures. All subjects underwent MRI with a mDIXON-Quant sequence and quantitative computed tomography (QCT), from which proton fat fraction-based bone marrow adipose tissue (BMAT) content and volumetric bone mineral density (vBMD) were measured, respectively. Nonlinear finite element analysis was applied to MRI and QCT scans of L2 vertebrae to compute vertebral strength (BMRI- and BCT-strength). The differences in BMAT content, vBMD, BMRI-strength and BCT-strength between the two groups were examined by t-tests. Receiver operating characteristic (ROC) analysis was performed to assess the ability of each measured parameter to distinguish fracture from non-fracture subjects. Results showed that the fracture group had 23 % lower BMRI-strength (P < .001) and 19 % higher BMAT content (P < .001) than the non-fracture group, whereas no significant difference in vBMD was detected between the two groups. A poor correlation was found between vBMD and BMRI-strength (R 2  = 0.33). Compared to vBMD and BMAT content, BMRI- and BCT-strength had the larger area under the curve (0.82 and 0.84, respectively) and provided better sensitivity and specificity in separating fracture from non-fracture subjects. In conclusion, BMRI is capable of detecting reduced bone strength in patients with vertebral fracture, and may serve as a new approach for risk assessment of vertebral fracture., Competing Interests: Declaration of competing interest The authors have no conflict of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background and Objective: Screw loosening remains a prominent problem for osteoporotic patients undergoing pedicle screw fixation surgeries but its underlying mechanisms are not fully understood. This study sought to examine the interactive effect of craniocaudal or axial cyclic loading (toggling) and osteoporosis on screw fixation., Methods: QCT-based finite element models of normal (n = 7; vBMD = 156 ± 13 mg/cm 3 ) and osteoporotic vertebrae (n = 7; vBMD = 72 ± 6 mg/cm 3 ) were inserted with pedicle screws and loaded with or without craniocaudal toggling. Among them, a representative normal vertebra (age: 55; BMD: 140 mg/cm 3 ) and an osteoporotic vertebra (age: 64; BMD: 79 mg/cm 3 ) were also loaded with or without axial toggling. The individual and interactive effects of craniocaudal toggling and osteoporosis on screw fixation strength (the force when the pull-up displacement of the screw head reached 1 mm) and bone tissue failure (characterized by equivalent plastic strain) were examined by repeated measure ANOVA., Results: A significant interactive effect between craniocaudal toggling and osteoporosis on screw fixation strength was detected (p = 0.008). Specifically, craniocaudal toggling led to a marked decrease in the fixation strength (68%, p < 0.05) and stiffness (83%, p < 0.05) only in the osteoporotic vertebrae but had no effect on screw fixation strength and stiffness of the normal vertebrae (p > 0.05). Likewise, most of the bone tissues around the screw in the osteoporotic vertebrae yielded following craniocaudal toggling whereas this result was not seen in the normal vertebrae. The axial toggling had no significant effect on bone tissue failure as well as pedicle screw fixation in normal or osteoporotic vertebrae., Conclusions: Craniocaudal toggling substantially reduces the screw fixation strength of the osteoporotic vertebrae by progressively increasing tissue failure around the screw, and therefore may contribute to the higher rates of screw loosening in osteoporotic compared to normal patients, whereas axial toggling is not a risk factor for pedicle screw loosening in normal or osteoporotic patients., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

To provide mechanistic insight into the etiology of osteoporotic wedge fractures, we investigated the spatial distribution of tissue at the highest risk of initial failure within the human vertebral body for both forward flexion and uniform compression loading conditions. Micro-CT-based linear elastic finite element analysis was used to virtually load 22 human T9 vertebral bodies in either 5° of forward flexion or uniform compression; we also ran analyses replacing the simulated compliant disc (E=8 MPa) with stiff polymethylmethacrylate (PMMA, E=2500 MPa). As expected, we found that, compared to uniform compression, forward flexion increased the overall endplate axial load on the anterior half of the vertebra and shifted the spatial distribution of high-risk tissue within the vertebra towards the anterior aspect of the vertebral body. However, despite that shift, the high-risk tissue remained primarily within the central regions of the trabecular bone and endplates, and forward flexion only slightly altered the ratio of cortical-to-trabecular load sharing at the mid-vertebral level (mean±SD for n=22: 41.3±7.4% compression; 44.1±8.2% forward flexion). When the compliant disc was replaced with PMMA, the anterior shift of high-risk tissue was much more severe. We conclude that, for a compliant disc, a moderate degree of forward flexion does not appreciably alter the spatial distribution of stress within the vertebral body., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The mechanism of vertebral wedge fractures remains unclear and may relate to typical variations in the mechanical behavior of the intervertebral disc. To gain insight, we tested 16 individual whole discs (between levels T8 and L5) from nine cadavers (mean±SD: 66±16 years), loaded in compression at different rates (0.05-20.0% strain/s), to measure a homogenized "effective" linear elastic modulus of the entire disc. The measured effective modulus, and average disc height, were then input and varied parametrically in micro-CT-based finite element models (60-μm element size, up to 80 million elements each) of six T9 human vertebrae that were virtually loaded to 3° of moderate forward-flexion via a homogenized disc. Across all specimens and loading rates, the measured effective modulus of the disc ranged from 5.8 to 42.7MPa and was significantly higher for higher rates of loading (p

Study Design: A prospective study. Purpose: To assess fat–water-like tissue changes on the 1st sacral vertebra using novel magnetic resonance imaging (MRI) phantom-based F- and W-scores and evaluate their diagnostic performances in osteoporosis detection. Overview of Literature: Using an uncommonly advanced MRI technique, previous studies have found that fat–water changes were consistent with osteoporosis. The role of routine MRI sequences can be extended in this regard. The S1 vertebra is considered a crucial anatomical site in spine surgeries because it seldom suffers from fractures. Thus, S1 could indicate osteoporotic fat–water changes. Methods: Forty-two female volunteers (aged 62.3±6.3 years) underwent spine examination with both MRI (including a phantom) and dual-energy X-ray absorptiometry (DXA) following ethical approval. MRI phantom-based F- and W-scoreS1 were defined by normalizing S1 vertebral signal intensities (SIs) by coconut oil and water SIs of the phantom on T1- and T2-weighted imaging, respectively. Using receiver operating characteristic analysis, the diagnostic performances of the new scores for evaluating osteoporosis and vertebral fractures were investigated against standard areal bone mineral density measured with DXA (DXA-aBMD). Results: The F-scoreS1 and W-scoreS1 were greater (4.11 and 2.43, respectively) in patients with osteoporosis than those without osteoporosis (3.25 and 1.92, respectively) and achieved areas under the curve (AUCs) of 0.82 and 0.76 (p<0.05), respectively, for osteoporosis detection. Similarly, the mean F-scoreS1 and W-scoreS1 were higher (4.11 and 2.63, respectively) in patients with vertebral fractures than in those without fractures (3.30 and 1.82, respectively) and had greater AUCs (0.90 for W-scoreS1 and 0.74 for F-scoreS1) than DXA-aBMD (AUC, 0.26; p<0.03). In addition, the F- and W-scoreS1 demonstrated a strong correlation (r=0.65, p<0.001). Conclusions: The new S1 vertebral-based MRI scores were developed to detect osteoporotic changes and demonstrated improvements over DXA-aBMD in differentiating patients with vertebral fractures. [ABSTRACT FROM AUTHOR]

Background: MRI‐based finite element analysis (MRI‐FEA) is the only method able to assess microstructural and whole‐bone mechanical properties of the hip in vivo. Purpose: To examine whether MRI‐FEA is capable of discriminating age‐related changes in whole‐bone mechanical performance and micromechanical behavior of the proximal femur, particularly considering the most common hip fracture‐related sideways fall loading. Study Type: Retrospective. Subjects: A total of nine younger (27 ± 3.2 years) and nine elderly (61 ± 3.9 years) healthy volunteers. Field Strength/Sequence: 3T; 3D fast field echo sequence. Assessment: The left proximal femurs were scanned and FE models created. FEA was performed to simulate sideways fall and stance loading for each femoral model. Apparent stiffness and high‐risk (90th percentile) tensile and compressive strains of the proximal femur as well as the average strains within cubic regions of the femoral neck and greater trochanter were assessed. Statistical Tests: Paired and unpaired t‐tests. Results: Compared to the young group, the femoral stiffness of the elderly decreased by 39% and 40% (both P < 0.05) under the sideways fall and stance conditions, respectively. Accordingly, the high‐risk tensile and compressive stains were elevated with aging (40% and 23% for sideways fall, 23% and 11% for stance conditions; all P < 0.05). However, the loading configuration‐induced difference was only observed in the elderly group for the high‐risk strains (22% for tension and 12% for compression; both P < 0.05). Additionally, compared to the stance condition, the sideways fall increased the average tensile (young: 108%, elderly: 123%; both P < 0.05) and compressive strains (young: 631%, elderly: 617%, both P < 0.05) within the greater trochanter rather than the femoral neck region. Data Conclusion: In vivo MRI‐FEA is capable of capturing age‐related changes in both apparent‐level stiffness and tissue‐level micromechanical behavior of the proximal femur. However, the effect of sideways fall loading might be better reflected by tissue‐level micromechanics rather than apparent stiffness. Level of Evidence: 3 Technical Efficacy Stage: 1 [ABSTRACT FROM AUTHOR]

Gerodermia osteodysplastica (GO) is a segmental progeroid disorder caused by loss-of-function mutations in the GORAB gene, associated with early onset osteoporosis and bone fragility. A conditional mouse model of GO ( Gorab Prx1 ) was generated in which the Gorab gene was deleted in long bones. We examined the biomechanical/functional relevance of the Gorab Prx1 mutants as a premature aging model by characterizing bone composition, tissue-level strains, and whole-bone morphology and mechanical properties of the tibia. MicroCT imaging showed that Gorab Prx1 tibiae had an increased anterior convex curvature and decreased cortical cross-sectional area, cortical thickness and moments of inertia, compared to littermate control (LC) tibiae. Fourier transform infrared (FTIR) imaging indicated a 34% decrease in mineral/matrix ratio and a 27% increase in acid phosphate content in the posterior metaphyseal cortex of the Gorab Prx1 tibiae (p < .05), suggesting delayed mineralization. In vivo strain gauge measurement and finite element analysis showed ∼two times higher tissue-level strains within the Gorab Prx1 tibiae relative to LC tibiae when subjected to axial compressive loads of the same magnitude. Three-point bending tests suggested that Gorab Prx1 tibiae were weaker and more brittle, as indicated by decreasing whole-bone strength (46%), stiffness (55%), work-to-fracture (61%) and post-yield displacement (47%). Many of these morphological and biomechanical characteristics of the Gorab Prx1 tibia recapitulated changes in other animal models of skeletal aging. Future studies are necessary to confirm how our observations might guide the way to a better understanding and treatment of GO. [ABSTRACT FROM AUTHOR]

Osteoporosis is characterized by reduced bone strength predisposing to an increased risk of fracture. Biomechanical computed tomography (BCT), predicting bone strength via CT-based finite element analysis (FEA), is now clinically available in the USA for diagnosing osteoporosis or assessing fracture risk. However, it has not been previously validated using a cohort of only Chinese subjects. Additionally, the effect of various modeling approaches on BCT outcomes remains elusive. To address these issues, we performed DXA and QCT scanning, compression testing, and BCT analyses on thirteen vertebrae derived from Chinese donors. Three BCT models were created (voxBCT and tetBCT: voxel-based and tetrahedral element-based FE models generated by a commercial software; matBCT: tetrahedral element-based FE model generated by a custom MATLAB program). BCT-computed outcomes were compared with experimental measures or between different BCT models. Results showed that, DXA-measured areal bone mineral density (aBMD) showed weak correlations with experimentally-measured vertebral stiffness (R2 = 0.28) and strength (R2 = 0.34). Compared to DXA-aBMD, BCT-computed stiffness provided improved correlations with experimentally-measured stiffness (voxBCT: R2 = 0.82; tetBCT: R2 = 0.77; matBCT: R2 = 0.76) and strength (voxBCT: R2 = 0.55; tetBCT: R2 = 0.57; matBCT: R2 = 0.53); BCT-computed mechanical parameters (stiffness, stress and strain) of the three different models were highly correlated with each other, with coefficient of determination (R2) values of 0.89–0.98. These results, based on a cohort of Chinese vertebral cadavers, suggest that BCT is superior over aBMD to consistently predict vertebral mechanical characteristics, regardless of the modeling approaches of choice. • Biomechanical computed tomography (BCT) was validated on a cohort of Chinese cadaveric vertebrae. • The effect of various modeling approaches (voxel vs tetrahedral element, commercial software vs custom program) was examined • BCT is superior over aBMD to predict vertebral mechanical characteristics, regardless of the modeling approaches of choice [ABSTRACT FROM AUTHOR]

Following primary fractures and percutaneous kyphoplasty (PKP), patients have a high risk of incurring a subsequent vertebral fracture (SVF). Given that SVF is a consequence of mechanical deterioration of the vertebra, we sought to examine whether vertebral strength derived from QCT-based finite element analysis (i.e., BCT) can predict the risk of SVF. Sixty-six patients who underwent PKP were categorized into two groups: control or non-SVF group (age: 70 ± 7 years; n = 40) and SVF group (age: 69 ± 8 years; n = 26). BCT was performed on L4 or L3 vertebrae to noninvasively measure vertebral strength. Vertebral strength was also estimated based upon the geometry and material properties of the vertebra. Additionally, trabecular volumetric bone mineral density (vBMD) and L1 Hounsfield unit (HU) were measured. t -Test, χ2 test or Mann Whitney U test were used to compare differences in these parameters between the two groups. The predictive abilities of BCT strength and other measured parameters were evaluated using the receiver operating characteristic (ROC) analysis. Results showed no significant difference in either vBMD or L1 HU between the control and SVF groups (p > 0.05), whereas BCT-computed and estimated vertebral strength values were significantly reduced by 33 % and 24 % for the SVF group relative to the non-SVF group, respectively. ROC curve indicated that BCT strength had the largest area under the curve, compared to other parameters. These results suggest that BCT-computed vertebral strength may serve as a surrogate for assessing risk of SVF. • The study aims to examine whether vertebral strength derived from BCT can predict the risk of SVF. • The BCT strength value is significantly reduced by 33 % for the SVF group relative to the non-SVF group. • The ROC curve indicates that BCT strength has the largest area under the curve. • There is no significant difference in either vBMD or L1 HU between the non-SVF and SVF groups. • The BCT strength may serve as a good predictor for assessing the risk of SVF. [ABSTRACT FROM AUTHOR]

• Our study sought to develop biomechanical CT for evaluating flexion strength based on Chinese vertebral cadavers. • Biomechanical CT predicts vertebral flexion strength better than bone mineral density. • Biomechanical CT, simulating either a uniform compression or a flexion loading condition, can consistently predict flexion strength. Biomechanical CT (BCT), i.e., quantitative computed tomography-based finite element analysis (QCT-FEA), promises an improved technique over bone mineral density (BMD) in predicting bone strength and the risk of osteoporotic vertebral fractures. However, most of the BCT models only consider a uniform compressive loading condition and they have not been validated for Chinese subjects. This study examined the ability of BCT to predict wedge fracture-related vertebral flexion strength in a cohort of Chinese cadaveric vertebrae. Twelve human vertebrae were scanned with dual energy X-ray absorptiometry (DXA) and QCT to measure areal and volumetric BMD, respectively. To produce wedge fractures, the cadaveric vertebrae were experimentally loaded until failure under a 15° flexion. Vertebral flexion stiffness and strength were measured from the force-displacement curve. Voxel-based heterogeneous FE models of the vertebrae were created and virtually tested in uniform compression and 15° flexion to compute compressive and flexion strength (and stiffness), respectively. The predictions of vertebral flexion strength with BMD or BCT measures were evaluated with linear regression analyses. Results showed weak correlations between experimentally-measured flexion strength vs. DXA-aBMD (R2 = 0.26) or QCT-vBMD (R2 = 0.39). However, there were strong correlations between experimentally-measured flexion strength vs. BCT-computed vertebral strength under either flexion (R2 = 0.71) or compression (R2 = 0.70) loading conditions, although flexion reduced the BCT-computed vertebral strength by 9.2%. These results suggest that, regardless of whether a uniform compression or a flexion loading is simulated, BCT can predict in vitro vertebral flexion strength better than BMD. [ABSTRACT FROM AUTHOR]