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Farzi M, Pozo JM, McCloskey E, Eastell R, Harvey NC, Frangi AF, Wilkinson JM. Quantitating Age-Related BMD Textural Variation from DXA Region-Free-Analysis: A Study of Hip Fracture Prediction in Three Cohorts. J Bone Miner Res 2022; 37:1679-1688. [PMID: 35748609 PMCID: PMC9541700 DOI: 10.1002/jbmr.4638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 05/24/2022] [Accepted: 06/17/2022] [Indexed: 11/21/2022]
Abstract
The risk of osteoporotic fracture is inversely related to bone mineral density (BMD), but how spatial BMD pattern influences fracture risk remains incompletely understood. This study used a pixel-level spatiotemporal atlas of proximal femoral BMD in 13,338 white European women (age 20-97 years) to quantitate age-related texture variation in BMD maps and generate a "reference" map of bone aging. We introduce a new index, called Densitometric Bone Age (DBA), as the age at which an individual site-specific BMD map (the proximal femur is studied here) best matches the median aging trajectory at that site in terms of the root mean squared error (RMSE). The ability of DBA to predict incident hip fracture and hip fracture pattern over 5 years following baseline BMD was compared against conventional region-based BMD analysis in a subset of 11,899 women (age 45-97 years), for which follow-up fracture records exist. There were 208 subsequent incident hip fractures in the study populations (138 femoral necks [FNs], 52 trochanteric [TR], 18 sites unspecified). DBA had modestly better performance compared to the conventional FN-BMD, TR-BMD, and total hip (TOT)-BMD in identifying hip fractures measured as the area under the curve (AUC) using receiver operating characteristics (ROC) curve analysis by 2% (95% confidence interval [CI], -0.5% to 3.5%), 3% (95% CI, 1.0% to 4.0%), and 1% (95% CI, 0.4% to 1.6%), respectively. Compared to FN-BMD T-score, DBA improved the ROC-AUC for predicting TR fractures by ~5% (95% CI, 1.1% to 9.8%) with similar performance in identifying FN fractures. Compared to TR-BMD T-score, DBA improved the ROC-AUC for the prediction of FN fractures by ~3% (95% CI, 1.1% to 4.9%), with similar performance in identifying TR fractures. Our findings suggest that DBA may provide a spatially sensitive measure of proximal femoral fragility that is not captured by FN-BMD or TR-BMD alone. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Mohsen Farzi
- Department of Oncology and MetabolismThe University of SheffieldSheffieldUK
- The Medical Research Council (MRC)‐Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), The University of SheffieldSheffieldUK
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB)The University of LeedsLeedsUK
| | - Jose M. Pozo
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB)The University of LeedsLeedsUK
| | - Eugene McCloskey
- Department of Oncology and MetabolismThe University of SheffieldSheffieldUK
- The Medical Research Council (MRC)‐Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), The University of SheffieldSheffieldUK
| | - Richard Eastell
- Department of Oncology and MetabolismThe University of SheffieldSheffieldUK
- The Medical Research Council (MRC)‐Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), The University of SheffieldSheffieldUK
| | - Nicholas C. Harvey
- The MRC Lifecourse Epidemiology CentreUniversity of SouthamptonSouthamptonUK
- NIHR Southampton Biomedical Research CentreUniversity of Southampton and University HospitalSouthamptonUK
| | - Alejandro F. Frangi
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB)The University of LeedsLeedsUK
| | - Jeremy Mark Wilkinson
- Department of Oncology and MetabolismThe University of SheffieldSheffieldUK
- The Medical Research Council (MRC)‐Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), The University of SheffieldSheffieldUK
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Clotet J, Martelli Y, Di Gregorio S, Del Río Barquero LM, Humbert L. Structural Parameters of the Proximal Femur by 3-Dimensional Dual-Energy X-ray Absorptiometry Software: Comparison With Quantitative Computed Tomography. J Clin Densitom 2018. [PMID: 28624339 DOI: 10.1016/j.jocd.2017.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Structural parameters of the proximal femur evaluate the strength of the bone and its susceptibility to fracture. These parameters are computed from dual-energy X-ray absorptiometry (DXA) or from quantitative computed tomography (QCT). The 3-dimensional (3D)-DXA software solution provides 3D models of the proximal femur shape and bone density from anteroposterior DXA scans. In this paper, we present and evaluate a new approach to compute structural parameters using 3D-DXA software. A cohort of 60 study subjects (60.9 ± 14.7 yr) with DXA and QCT examinations was collected. 3D femoral models obtained by QCT and 3D-DXA software were aligned using rigid registration techniques for comparison purposes. Geometric, cross-sectional, and volumetric structural parameters were computed at the narrow neck, intertrochanteric, and lower shaft regions for both QCT and 3D-DXA models. The accuracy of 3D-DXA structural parameters was evaluated in comparison with QCT. Correlation coefficients (r) between geometric parameters computed by QCT and 3D-DXA software were 0.86 for the femoral neck axis length and 0.71 for the femoral neck shaft angle. Correlation coefficients ranged from 0.86 to 0.96 for the cross-sectional parameters and from 0.84 to 0.97 for the volumetric structural parameters. Our study demonstrated that accurate estimates of structural parameters for the femur can be obtained from 3D-DXA models. This provides clinicians with 3D indexes related to the femoral strength from routine anteroposterior DXA scans, which could potentially improve osteoporosis management and fracture prevention.
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Affiliation(s)
- Jordi Clotet
- Musculoskeletal Unit, Galgo Medical, Barcelona, Spain
| | - Yves Martelli
- Musculoskeletal Unit, Galgo Medical, Barcelona, Spain
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Nagarajan MB, Coan P, Huber MB, Diemoz PC, Wismüller A. Volumetric quantitative characterization of human patellar cartilage with topological and geometrical features on phase-contrast X-ray computed tomography. Med Biol Eng Comput 2015; 53:1211-20. [PMID: 26142112 PMCID: PMC4630098 DOI: 10.1007/s11517-015-1340-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 06/22/2015] [Indexed: 01/19/2023]
Abstract
Phase-contrast X-ray computed tomography (PCI-CT) has attracted significant interest in recent years for its ability to provide significantly improved image contrast in low absorbing materials such as soft biological tissue. In the research context of cartilage imaging, previous studies have demonstrated the ability of PCI-CT to visualize structural details of human patellar cartilage matrix and capture changes to chondrocyte organization induced by osteoarthritis. This study evaluates the use of geometrical and topological features for volumetric characterization of such chondrocyte patterns in the presence (or absence) of osteoarthritic damage. Geometrical features derived from the scaling index method (SIM) and topological features derived from Minkowski Functionals were extracted from 1392 volumes of interest (VOI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These features were subsequently used in a machine learning task with support vector regression to classify VOIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver operating characteristic curve (AUC). Our results show that the classification performance of SIM-derived geometrical features (AUC: 0.90 ± 0.09) is significantly better than Minkowski Functionals volume (AUC: 0.54 ± 0.02), surface (AUC: 0.72 ± 0.06), mean breadth (AUC: 0.74 ± 0.06) and Euler characteristic (AUC: 0.78 ± 0.04) (p < 10(-4)). These results suggest that such geometrical features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix in an automated manner, while also enabling classification of cartilage as healthy or osteoarthritic with high accuracy. Such features could potentially serve as diagnostic imaging markers for evaluating osteoarthritis progression and its response to different therapeutic intervention strategies.
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Affiliation(s)
- Mahesh B Nagarajan
- Departments of Imaging Sciences and Biomedical Engineering, University of Rochester, Rochester, NY, USA.
| | - Paola Coan
- Faculty of Medicine & Institute of Clinical Radiology, Ludwig Maximilians University, 80336, Munich, Germany
- Department of Physics, Ludwig Maximilians University, 85748, Munich, Germany
- European Synchrotron Radiation Facility, 38000, Grenoble, France
| | - Markus B Huber
- Departments of Imaging Sciences and Biomedical Engineering, University of Rochester, Rochester, NY, USA
| | - Paul C Diemoz
- Department of Physics, Ludwig Maximilians University, 85748, Munich, Germany
- European Synchrotron Radiation Facility, 38000, Grenoble, France
| | - Axel Wismüller
- Departments of Imaging Sciences and Biomedical Engineering, University of Rochester, Rochester, NY, USA
- Faculty of Medicine & Institute of Clinical Radiology, Ludwig Maximilians University, 80336, Munich, Germany
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KAYALVIZHI M, ANANDH KR, KAVITHA G, SUJATHA CM, RAMAKRISHNAN S. ANALYSIS OF ANATOMICAL REGIONS IN ALZHEIMER'S BRAIN MR IMAGES USING LEVEL SETS AND MINKOWSKI FUNCTIONALS. J MECH MED BIOL 2015. [DOI: 10.1142/s0219519415400242] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this work, an attempt is made to analyze anatomical regions of Alzheimer's brain MR images using level set and Minkowski functionals (MFs). The T1 weighted sagittal view of normal and abnormal images considered in this work, are obtained from MIRIAD database. The ventricle along with the hippocampus is segmented using Reaction Diffusion (RD) level set method and is subjected to further analysis using MFs. The prominent feature derived from the segmented region which contains ventricle and hippocampus is correlated with the Mini-Mental State Examination (MMSE) score. Results show that RD method is able to delineate the exact boundary of the ventricle along with hippocampus. It is observed that the MF-area of segmented region provides better discrimination of normal and abnormal subjects (p < 0.001) compared to the MF-perimeter and MF-Euler number. The correlation of the MMSE with prominent MF-area for normal, mild, moderate and severe are found to be 0.71, 0.82, 0.84 and 0.89, respectively. This suggests that characterization of brain structures using MFs improve the discrimination capability of brain disorders. Hence MF-area feature could be used for the study of progression in Alzheimer's disease (AD) like neurodegenerative disorders.
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Affiliation(s)
- M. KAYALVIZHI
- Department of Electronics Engineering, Madras Institute of Technology, Anna University, Chennai-600 044, India
| | - K. R. ANANDH
- Department of ECE, College of Engineering, Guindy, Anna University, Chennai-600 025, India
| | - G. KAVITHA
- Department of Electronics Engineering, Madras Institute of Technology, Anna University, Chennai-600 044, India
| | - C. M. SUJATHA
- Department of ECE, College of Engineering, Guindy, Anna University, Chennai-600 025, India
| | - S. RAMAKRISHNAN
- Non-Invasive Imaging and Diagnostics Laboratory, Biomedical Engineering Group, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai-600 036, India
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Dong XN, Pinninti R, Lowe T, Cussen P, Ballard JE, Di Paolo D, Shirvaikar M. Random field assessment of inhomogeneous bone mineral density from DXA scans can enhance the differentiation between postmenopausal women with and without hip fractures. J Biomech 2015; 48:1043-51. [PMID: 25683520 DOI: 10.1016/j.jbiomech.2015.01.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/05/2015] [Accepted: 01/26/2015] [Indexed: 11/19/2022]
Abstract
Bone mineral density (BMD) measurements from Dual-energy X-ray Absorptiometry (DXA) alone cannot account for all factors associated with the risk of hip fractures. For example, the inhomogeneity of bone mineral density in the hip region also contributes to bone strength. In the stochastic assessment of bone inhomogeneity, the BMD map in the hip region is considered as a random field and stochastic predictors can be calculated by fitting a theoretical model onto the experimental variogram of the BMD map. The objective of this study was to compare the ability of bone mineral density and stochastic assessment of inhomogeneous distribution of bone mineral density in predicting hip fractures for postmenopausal women. DXA scans in the hip region were obtained from postmenopausal women with hip fractures (N=47, Age: 71.3±11.4 years) and without hip fractures (N=45, Age: 66.7±11.4 years). Comparison of BMD measurements and stochastic predictors in assessing bone fragility was based on the area under the receiver operating characteristic curves (AUC) from logistic regression analyses. Although stochastic predictors offered higher accuracy (AUC=0.675) in predicting the risk of hip fractures than BMD measurements (AUC=0.625), this difference was not statistically significant (p=0.548). Nevertheless, the combination of stochastic predictors and BMD measurements had significantly (p=0.039) higher prediction accuracy (AUC=0.748) than BMD measurements alone. This study demonstrates that stochastic assessment of bone mineral distribution from DXA scans can serve as a valuable tool in enhancing the prediction of hip fractures for postmenopausal women in addition to BMD measurements.
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Affiliation(s)
- Xuanliang Neil Dong
- Department of Health and Kinesiology, The University of Texas at Tyler, 3900 University Boulevard, Tyler, TX 75799, USA.
| | - Rajeshwar Pinninti
- Department of Electrical Engineering, The University of Texas at Tyler, Tyler, TX 75799, USA
| | - Timothy Lowe
- Department of Health and Kinesiology, The University of Texas at Tyler, 3900 University Boulevard, Tyler, TX 75799, USA
| | - Patricia Cussen
- Department of Radiology, UT Health Northeast, Tyler, TX 75708, USA
| | - Joyce E Ballard
- Department of Health and Kinesiology, The University of Texas at Tyler, 3900 University Boulevard, Tyler, TX 75799, USA
| | - David Di Paolo
- Department of Health and Kinesiology, The University of Texas at Tyler, 3900 University Boulevard, Tyler, TX 75799, USA; Department of Radiology, UT Health Northeast, Tyler, TX 75708, USA
| | - Mukul Shirvaikar
- Department of Electrical Engineering, The University of Texas at Tyler, Tyler, TX 75799, USA
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6
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Ulivieri FM, Silva BC, Sardanelli F, Hans D, Bilezikian JP, Caudarella R. Utility of the trabecular bone score (TBS) in secondary osteoporosis. Endocrine 2014; 47:435-48. [PMID: 24853880 DOI: 10.1007/s12020-014-0280-4] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 04/25/2014] [Indexed: 12/17/2022]
Abstract
Altered bone micro-architecture is an important factor in accounting for fragility fractures. Until recently, it has not been possible to gain information about skeletal microstructure in a way that is clinically feasible. Bone biopsy is essentially a research tool. High-resolution peripheral Quantitative Computed Tomography, while non-invasive, is available only sparsely throughout the world. The trabecular bone score (TBS) is an imaging technology adapted directly from the Dual Energy X-Ray Absorptiometry (DXA) image of the lumbar spine. Thus, it is potentially readily and widely available. In recent years, a large number of studies have demonstrated that TBS is significantly associated with direct measurements of bone micro-architecture, predicts current and future fragility fractures in primary osteoporosis, and may be a useful adjunct to BMD for fracture detection and prediction. In this review, we summarize its potential utility in secondary causes of osteoporosis. In some situations, like glucocorticoid-induced osteoporosis and in diabetes mellitus, the TBS appears to out-perform DXA. It also has apparent value in numerous other disorders associated with diminished bone health, including primary hyperparathyroidism, androgen-deficiency, hormone-receptor positive breast cancer treatment, chronic kidney disease, hemochromatosis, and autoimmune disorders like rheumatoid arthritis. Further research is both needed and warranted to more clearly establish the role of TBS in these and other disorders that adversely affect bone.
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Affiliation(s)
- Fabio M Ulivieri
- Bone Metabolic Unit, Division of Nuclear Medicine, Fondazione Irccs Ca' Ospedale Maggiore Policlinico, Milan, Italy
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7
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Piodi LP, Poloni A, Ulivieri FM. Managing osteoporosis in ulcerative colitis: something new? World J Gastroenterol 2014; 20:14087-98. [PMID: 25339798 PMCID: PMC4202340 DOI: 10.3748/wjg.v20.i39.14087] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 05/12/2014] [Accepted: 06/26/2014] [Indexed: 02/06/2023] Open
Abstract
The authors revise the latest evidence in the literature regarding managing of osteoporosis in ulcerative colitis (UC), paying particular attention to the latest tendency of the research concerning the management of bone damage in the patient affected by UC. It is wise to assess vitamin D status in ulcerative colitis patients to recognize who is predisposed to low levels of vitamin D, whose deficiency has to be treated with oral or parenteral vitamin D supplementation. An adequate dietary calcium intake or supplementation and physical activity, if possible, should be guaranteed. Osteoporotic risk factors, such as smoking and excessive alcohol intake, must be avoided. Steroid has to be prescribed at the lowest possible dosage and for the shortest possible time. Moreover, conditions favoring falling have to been minimized, like carpets, low illumination, sedatives assumption, vitamin D deficiency. It is advisable to assess the fracture risk in all UC patient by the fracture assessment risk tool (FRAX(®) tool), that calculates the ten years risk of fracture for the population aged from 40 to 90 years in many countries of the world. A high risk value could indicate the necessity of treatment, whereas a low risk value suggests a follow-up only. An intermediate risk supports the decision to prescribe bone mineral density (BMD) assessment and a subsequent patient revaluation for treatment. Dual energy X-ray absorptiometry bone densitometry can be used not only for BMD measurement, but also to collect data about bone quality by the means of trabecular bone score and hip structural analysis assessment. These two indices could represent a method of interesting perspectives in evaluating bone status in patients affected by diseases like UC, which may present an impairment of bone quality as well as of bone quantity. In literature there is no strong evidence for instituting pharmacological therapy of bone impairment in UC patients for clinical indications other than those that are also applied to the patients with osteoporosis. Therefore, a reasonable advice is to consider pharmacological treatment for osteoporosis in those UC patients who already present fragility fractures, which bring a high risk of subsequent fractures. Therapy has also to be considered in patients with a high risk of fracture even if it did not yet happen, and particularly when they had long periods of corticosteroid therapy or cumulative high dosages. In patients without fragility fractures or steroid treatment, a medical decision about treatment could be guided by the FRAX tool to determine the intervention threshold. Among drugs for osteoporosis treatment, the bisphosphonates are the most studied ones, with the best and longest evidence of efficacy and safety. Despite this, several questions are still open, such as the duration of treatment, the necessity to discontinue it, the indication of therapy in young patients, particularly in those without previous fractures. Further, it has to be mentioned that a long-term bisphosphonates use in primary osteoporosis has been associated with an increased incidence of dramatic side-effects, even if uncommon, like osteonecrosis of the jaw and atypical sub-trochanteric and diaphyseal femoral fractures. UC is a long-lasting disease and the majority of patients is relatively young. In this scenario primary prevention of fragility fracture is the best cost-effective strategy. Vitamin D supplementation, adequate calcium intake, suitable physical activity (when possible), removing of risk factors for osteoporosis like smoking, and avoiding falling are the best medical acts.
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8
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Silva BC, Leslie WD, Resch H, Lamy O, Lesnyak O, Binkley N, McCloskey EV, Kanis JA, Bilezikian JP. Trabecular bone score: a noninvasive analytical method based upon the DXA image. J Bone Miner Res 2014; 29:518-30. [PMID: 24443324 DOI: 10.1002/jbmr.2176] [Citation(s) in RCA: 532] [Impact Index Per Article: 53.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 01/11/2014] [Accepted: 01/14/2014] [Indexed: 12/16/2022]
Abstract
The trabecular bone score (TBS) is a gray-level textural metric that can be extracted from the two-dimensional lumbar spine dual-energy X-ray absorptiometry (DXA) image. TBS is related to bone microarchitecture and provides skeletal information that is not captured from the standard bone mineral density (BMD) measurement. Based on experimental variograms of the projected DXA image, TBS has the potential to discern differences between DXA scans that show similar BMD measurements. An elevated TBS value correlates with better skeletal microstructure; a low TBS value correlates with weaker skeletal microstructure. Lumbar spine TBS has been evaluated in cross-sectional and longitudinal studies. The following conclusions are based upon publications reviewed in this article: 1) TBS gives lower values in postmenopausal women and in men with previous fragility fractures than their nonfractured counterparts; 2) TBS is complementary to data available by lumbar spine DXA measurements; 3) TBS results are lower in women who have sustained a fragility fracture but in whom DXA does not indicate osteoporosis or even osteopenia; 4) TBS predicts fracture risk as well as lumbar spine BMD measurements in postmenopausal women; 5) efficacious therapies for osteoporosis differ in the extent to which they influence the TBS; 6) TBS is associated with fracture risk in individuals with conditions related to reduced bone mass or bone quality. Based on these data, lumbar spine TBS holds promise as an emerging technology that could well become a valuable clinical tool in the diagnosis of osteoporosis and in fracture risk assessment.
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Affiliation(s)
- Barbara C Silva
- Metabolic Bone Diseases Unit, Division of Endocrinology, Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Nagarajan MB, Huber MB, Schlossbauer T, Leinsinger G, Krol A, Wismüller A. Classification of small lesions in dynamic breast MRI: Eliminating the need for precise lesion segmentation through spatio-temporal analysis of contrast enhancement over time. MACHINE VISION AND APPLICATIONS 2013; 24:10.1007/s00138-012-0456-y. [PMID: 24244074 PMCID: PMC3826664 DOI: 10.1007/s00138-012-0456-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Characterizing the dignity of breast lesions as benign or malignant is specifically difficult for small lesions; they don't exhibit typical characteristics of malignancy and are harder to segment since margins are harder to visualize. Previous attempts at using dynamic or morphologic criteria to classify small lesions (mean lesion diameter of about 1 cm) have not yielded satisfactory results. The goal of this work was to improve the classification performance in such small diagnostically challenging lesions while concurrently eliminating the need for precise lesion segmentation. To this end, we introduce a method for topological characterization of lesion enhancement patterns over time. Three Minkowski Functionals were extracted from all five post-contrast images of sixty annotated lesions on dynamic breast MRI exams. For each Minkowski Functional, topological features extracted from each post-contrast image of the lesions were combined into a high-dimensional texture feature vector. These feature vectors were classified in a machine learning task with support vector regression. For comparison, conventional Haralick texture features derived from gray-level co-occurrence matrices (GLCM) were also used. A new method for extracting thresholded GLCM features was also introduced and investigated here. The best classification performance was observed with Minkowski Functionals area and perimeter, thresholded GLCM features f8 and f9, and conventional GLCM features f4 and f6. However, both Minkowski Functionals and thresholded GLCM achieved such results without lesion segmentation while the performance of GLCM features significantly deteriorated when lesions were not segmented (p < 0.05). This suggests that such advanced spatio-temporal characterization can improve the classification performance achieved in such small lesions, while simultaneously eliminating the need for precise segmentation.
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Affiliation(s)
- Mahesh B. Nagarajan
- Department of Imaging Sciences and Biomedical Engineering, University of Rochester, 207 Robert B. Goergen Hall, Rochester NY 14627, USA
| | - Markus B. Huber
- Department of Imaging Sciences and Biomedical Engineering, University of Rochester, 207 Robert B. Goergen Hall, Rochester NY 14627, USA
| | - Thomas Schlossbauer
- Department of Radiology, Ludwig Maximilians Universität, Klinikum Innenstadt, Ziemssenstr.1,80336 München, Germany
| | - Gerda Leinsinger
- Department of Radiology, Ludwig Maximilians Universität, Klinikum Innenstadt, Ziemssenstr.1,80336 München, Germany
| | - Andrzej Krol
- Department of Radiology, SUNY Upstate Medical University, 750 E. Adams Street, Syracuse NY 13210, USA
| | - Axel Wismüller
- Department of Imaging Sciences and Biomedical Engineering, University of Rochester, 207 Robert B. Goergen Hall, Rochester NY 14627, USA. Department of Radiology, Ludwig Maximilians Universität, Klinikum Innenstadt, Ziemssenstr.1,80336 München, Germany
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10
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Grote S, Noeldeke T, Blauth M, Mutschler W, Bürklein D. Mechanical torque measurement in the proximal femur correlates to failure load and bone mineral density ex vivo. Orthop Rev (Pavia) 2013; 5:77-81. [PMID: 23888206 PMCID: PMC3718240 DOI: 10.4081/or.2013.e16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/21/2013] [Accepted: 05/22/2013] [Indexed: 12/03/2022] Open
Abstract
Knowledge of local bone quality is essential for surgeons to determine operation techniques. A device for intraoperative measurement of local bone quality has been developed by the AO-Research Foundation (Densi - Probe®). We used this device to experimentally measure peak breakaway torque of trabecular bone in the proximal femur and correlated this with local bone mineral density (BMD) and failure load. Bone mineral density of 160 cadaver femurs was measured by ex situ dualenergy X-ray absorptiometry. The failure load of all femurs was analyzed by side-impact analysis. Femur fractures were fixed and mechanical peak torque was measured with the DensiProbe® device. Correlation was calculated whereas correlation coefficient and significance was calculated by Fisher’s Ztransformation. Moreover, linear regression analysis was carried out. The unpaired Student’s t-test was used to assess the significance of differences. The Ward triangle region had the lowest BMD with 0.511 g/cm2 (±0.17 g/cm2), followed by the upper neck region with 0.546 g/cm2 (±0.16 g/cm2), trochanteric region with 0.685 g/cm2 (±0.19 g/cm2) and the femoral neck with 0.813 g/cm2 (±0.2 g/cm2). Peak torque of DensiProbe® in the femoral head was 3.48 Nm (±2.34 Nm). Load to failure was 4050.2 N (±1586.7 N). The highest correlation of peak torque measured by Densi Probe® and load to failure was found in the femoral neck (r=0.64, P<0.001). The overall correlation of mechanical peak torque with T-score was r=0.60 (P<0.001). A correlation was found between mechanical peak torque, load to failure of bone and BMD in vitro. Trabecular strength of bone and bone mineral density are different aspects of bone strength, but a correlation was found between them. Mechanical peak torque as measured may contribute additional information about bone strength, especially in the perioperative testing.
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Affiliation(s)
- Stefan Grote
- Department of Trauma Surgery, University of Munich, Campus Innenstadt , Munich, Germany
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11
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Nagarajan MB, Coan P, Huber MB, Diemoz PC, Glaser C, Wismuller A. Computer-aided diagnosis in phase contrast imaging X-ray computed tomography for quantitative characterization of ex vivo human patellar cartilage. IEEE Trans Biomed Eng 2013; 60:2896-903. [PMID: 23744660 DOI: 10.1109/tbme.2013.2266325] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Visualization of ex vivo human patellar cartilage matrix through the phase contrast imaging X-ray computed tomography (PCI-CT) has been previously demonstrated. Such studies revealed osteoarthritis-induced changes to chondrocyte organization in the radial zone. This study investigates the application of texture analysis to characterizing such chondrocyte patterns in the presence and absence of osteoarthritic damage. Texture features derived from Minkowski functionals (MF) and gray-level co-occurrence matrices (GLCM) were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These texture features were subsequently used in a machine learning task with support vector regression to classify ROIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver operating characteristic curve (AUC). The best classification performance was observed with the MF features perimeter (AUC: 0.94 ±0.08 ) and "Euler characteristic" (AUC: 0.94 ±0.07 ), and GLCM-derived feature "Correlation" (AUC: 0.93 ±0.07). These results suggest that such texture features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix, enabling classification of cartilage as healthy or osteoarthritic with high accuracy.
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Güerri-Fernández RC, Nogués X, Quesada Gómez JM, Torres Del Pliego E, Puig L, García-Giralt N, Yoskovitz G, Mellibovsky L, Hansma PK, Díez-Pérez A. Microindentation for in vivo measurement of bone tissue material properties in atypical femoral fracture patients and controls. J Bone Miner Res 2013; 28:162-8. [PMID: 22887720 DOI: 10.1002/jbmr.1731] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 07/16/2012] [Accepted: 07/20/2012] [Indexed: 11/09/2022]
Abstract
Atypical femoral fractures (AFF) associated with long-term bisphosphonates (LTB) are a growing concern. Their etiology is unknown, but bone material properties might be deteriorated. In an AFF series, we analyzed the bone material properties by microindentation. Four groups of patients were included: 6 AFF, 38 typical osteoporotic fractures, 6 LTB, and 20 controls without fracture. Neither typical osteoporotic fractures nor controls have received any antiosteoporotic medication. A general laboratory workup, bone densitometry by dual-energy X-ray absorptiometry (DXA), and microindentation testing at the tibia were done in all patients. Total indentation distance (Total ID), indentation distance increase (IDI), and creep indentation distance (Creep ID) were measured (microns). Age-adjusted analysis of covariance (ANCOVA) was used for comparisons. Controls were significantly younger than fracture groups. Bisphosphonate exposure was on average 5.5 years (range 5 to 12 years) for the AFF and 5.4 years (range 5 to 8 years) for the LTB groups. Total ID (microns) showed better material properties (lower Total ID) for controls 36 (± 6; mean ± SD) than for AFF 46 (± 4) and for typical femoral fractures 47 (± 13), respectively. Patients on LTB showed values between controls and fractures, 38 (± 4), although not significantly different from any of the other three groups. IDI values showed a similar pattern 13 (± 2), 16 (± 6), 19 (± 3), and 18 (± 5). After adjusting by age, significant differences were seen between controls and typical (p < 0.001) and atypical fractures (p = 0.03) for Total ID and for IDI (p < 0.001 and p < 0.05, respectively). There were no differences in Creep ID between groups. Our data suggest that patients with AFF have a deep deterioration in bone material properties at a tissue level similar to that for the osteoporotic fracture group. The LTB group shows levels that are in between controls and both type of fractures, although not statistically different. These results suggest that bisphosphonate therapy probably does not put the majority of patients at risk for AFF.
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[Treatment results after cemented hemiprosthesis for care of unstable pertrochanteric femoral fractures in the elderly]. Unfallchirurg 2012; 115:234-42. [PMID: 21161152 DOI: 10.1007/s00113-010-1884-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND The optimal treatment strategy for unstable trochanteric fractures in the elderly is still controversial because of the frequent failure of osteosynthesis. METHODS A cohort of patients with unstable trochanteric fractures who were treated with cemented hemiarthroplasty and presented in our department during the period 2003-2009 was analyzed. Complications, reoperations, walking ability and full weight bearing were documented. RESULTS A total of 91 patients were included (mean age 87.7±6.8 years) and predominantly 31A2 fractures (89%) were treated. There were 3.3% reoperations in the cohort and the 30 day mortality was 5.5%. At least 1 general complication occurred in over 50% of the patients. However, 30% of the patients had lower urinary tract infections, disturbances of electrolyte balance or transitory psychotic symptoms. On average full weight bearing could be performed at 3.5 (±3) days after the operation. CONCLUSION Cemented hemiarthroplasty is a safe treatment strategy for unstable trochanteric fractures in the elderly, which allows early full weight bearing. Because of frequent general complications, more interdisciplinary units and centres of excellence are needed to handle this challenging cohort.
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Hans D, Barthe N, Boutroy S, Pothuaud L, Winzenrieth R, Krieg MA. Correlations between trabecular bone score, measured using anteroposterior dual-energy X-ray absorptiometry acquisition, and 3-dimensional parameters of bone microarchitecture: an experimental study on human cadaver vertebrae. J Clin Densitom 2011; 14:302-12. [PMID: 21724435 DOI: 10.1016/j.jocd.2011.05.005] [Citation(s) in RCA: 296] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 05/16/2011] [Accepted: 05/17/2011] [Indexed: 12/27/2022]
Abstract
Developing a novel technique for the efficient, noninvasive clinical evaluation of bone microarchitecture remains both crucial and challenging. The trabecular bone score (TBS) is a new gray-level texture measurement that is applicable to dual-energy X-ray absorptiometry (DXA) images. Significant correlations between TBS and standard 3-dimensional (3D) parameters of bone microarchitecture have been obtained using a numerical simulation approach. The main objective of this study was to empirically evaluate such correlations in anteroposterior spine DXA images. Thirty dried human cadaver vertebrae were evaluated. Micro-computed tomography acquisitions of the bone pieces were obtained at an isotropic resolution of 93μm. Standard parameters of bone microarchitecture were evaluated in a defined region within the vertebral body, excluding cortical bone. The bone pieces were measured on a Prodigy DXA system (GE Medical-Lunar, Madison, WI), using a custom-made positioning device and experimental setup. Significant correlations were detected between TBS and 3D parameters of bone microarchitecture, mostly independent of any correlation between TBS and bone mineral density (BMD). The greatest correlation was between TBS and connectivity density, with TBS explaining roughly 67.2% of the variance. Based on multivariate linear regression modeling, we have established a model to allow for the interpretation of the relationship between TBS and 3D bone microarchitecture parameters. This model indicates that TBS adds greater value and power of differentiation between samples with similar BMDs but different bone microarchitectures. It has been shown that it is possible to estimate bone microarchitecture status derived from DXA imaging using TBS.
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Affiliation(s)
- Didier Hans
- Department of Bone and Joint Diseases, Lausanne University Hospital, Lausanne, Switzerland
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Huber MB, Carballido-Gamio J, Fritscher K, Schubert R, Haenni M, Hengg C, Majumdar S, Link TM. Development and testing of texture discriminators for the analysis of trabecular bone in proximal femur radiographs. Med Phys 2010; 36:5089-98. [PMID: 19994519 DOI: 10.1118/1.3215535] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Texture analysis of femur radiographs may serve as a potential low cost technique to predict osteoporotic fracture risk and has received considerable attention in the past years. A further application of this technique may be the measurement of the quality of specific bone compartments to provide useful information for treatment of bone fractures. Two challenges of texture analysis are the selection of the best suitable texture measure and reproducible placement of regions of interest (ROIs). The goal of this in vitro study was to automatically place ROIs in radiographs of proximal femur specimens and to calculate correlations between various different texture analysis methods and the femurs' anchorage strength. METHODS Radiographs were obtained from 14 femoral specimens and bone mineral density (BMD) was measured in the femoral neck. Biomechanical testing was performed to assess the anchorage strength in terms of failure load, breakaway torque, and number of cycles. Images were segmented using a framework that is based on the usage of level sets and statistical in-shape models. Five ROIs were automatically placed in the head, upper and lower neck, trochanteric, and shaft compartment in an atlas subject. All other subjects were registered rigidly, affinely, and nonlinearly, and the resulting transformation was used to map the five ROIs onto the individual femora. RESULTS In each ROI, texture features were extracted using gray level co-occurence matrices (GLCM), third-order GLCM, morphological gradients (MGs), Minkowski dimensions (MDs), Minkowski functionals (MFs), Gaussian Markov random fields, and scaling index method (SIM). Coefficients of determination for each texture feature with parameters of anchorage strength were computed. In a stepwise multiregression analysis, the most predictive parameters were identified in different models. Texture features were highly correlated with anchorage strength estimated by the failure load of up to R2=0.61 (MF and MG features, p<0.01) and were partially independent of BMD. The correlations were dependent on the choice of the ROI and the texture measure. The best predictive multiregression model for failure load R2adj=0.86 (p<0.001) included a set of recently developed texture methods (MF and SIM) but excluded bone mineral density and commonly used texture measures. CONCLUSIONS The results suggest that texture information contained in trabecular bone structure visualized on radiographs may predict whether an implant anchorage can be used and may determine the local bone quality from preoperative radiographs.
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Affiliation(s)
- M B Huber
- Department of Radiology and Biomedical Imaging, University of California, 400 Parnassus Avenue, San Francisco, California 94143, USA.
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Trabecular bone structure analysis in the osteoporotic spine using a clinical in vivo setup for 64-slice MDCT imaging: comparison to microCT imaging and microFE modeling. J Bone Miner Res 2009; 24:1628-37. [PMID: 19338434 PMCID: PMC6961533 DOI: 10.1359/jbmr.090311] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Assessment of trabecular microarchitecture may improve estimation of biomechanical strength, but visualization of trabecular bone structure in vivo is challenging. We tested the feasibility of assessing trabecular microarchitecture in the spine using multidetector CT (MDCT) on intact human cadavers in an experimental in vivo-like setup. BMD, bone structure (e.g., bone volume/total volume = BV/TV; trabecular thickness = Tb.Th; structure model index = SMI) and bone texture parameters were evaluated in 45 lumbar vertebral bodies using MDCT (mean in-plane pixel size, 274 microm(2); slice thickness, 500 microm). These measures were correlated with structure measures assessed with microCT at an isotropic spatial resolution of 16 microm and to microfinite element models (microFE) of apparent modulus and stiffness. MDCT-derived BMD and structure measures showed significant correlations to the density and structure obtained by microCT (BMD, R(2) = 0.86, p < 0.0001; BV/TV, R(2) = 0.64, p < 0.0001; Tb.Th, R(2) = 0.36, p < 0.01). When comparing microCT-derived measures with microFE models, the following correlations (p < 0.001) were found for apparent modulus and stiffness, respectively: BMD (R(2) = 0.58 and 0.66), BV/TV (R(2) = 0.44 and 0.58), and SMI (R(2) = 0.44 and 0.49). However, the overall highest correlation (p < 0.001) with microFE app. modulus (R(2) = 0.75) and stiffness (R(2) = 0.76) was achieved by the combination of QCT-derived BMD with the bone texture measure Minkowski Dimension. In summary, although still limited by its spatial resolution, trabecular bone structure assessment using MDCT is overall feasible. However, when comparing with microFE-derived bone properties, BMD is superior compared with single parameters for microarchitecture, and correlations further improve when combining with texture measures.
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Canuto HC, McLachlan C, Kettunen MI, Velic M, Krishnan AS, Neves AA, de Backer M, Hu DE, Hobson MP, Brindle KM. Characterization of image heterogeneity using 2D Minkowski functionals increases the sensitivity of detection of a targeted MRI contrast agent. Magn Reson Med 2009; 61:1218-24. [PMID: 19253374 DOI: 10.1002/mrm.21946] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A targeted Gd(3+)-based contrast agent has been developed that detects tumor cell death by binding to the phosphatidylserine (PS) exposed on the plasma membrane of dying cells. Although this agent has been used to detect tumor cell death in vivo, the differences in signal intensity between treated and untreated tumors was relatively small. As cell death is often spatially heterogeneous within tumors, we investigated whether an image analysis technique that parameterizes heterogeneity could be used to increase the sensitivity of detection of this targeted contrast agent. Two-dimensional (2D) Minkowski functionals (MFs) provided an automated and reliable method for parameterization of image heterogeneity, which does not require prior assumptions about the number of regions or features in the image, and were shown to increase the sensitivity of detection of the contrast agent as compared to simple signal intensity analysis.
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Affiliation(s)
- Holly C Canuto
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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Boehm HF, Lutz J, Horng A, Notohamiprodjo M, Panteleon A, Pfeifer KJ, Reiser M. Local topological analysis of densitometer-generated scan images of the proximal femur for differentiation between patients with hip fracture and age-matched controls. Osteoporos Int 2009; 20:617-24. [PMID: 18685880 DOI: 10.1007/s00198-008-0706-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Accepted: 06/23/2008] [Indexed: 01/09/2023]
Abstract
SUMMARY We evaluate densitometer-generated scan images of the proximal femur with respect to topological properties of bone mineral distribution patterns in selected regions of interest. In a population of 100 post-menopausal women, the method has a highly discriminative potential with a performance superior to standard densitometry. Results vary with anatomical location within the proximal femur. INTRODUCTION The objectives of the study were to evaluate densitometer-generated scan images of the proximal femur with respect to topological properties of bone mineral distribution patterns in selected regions of interest, to test the ability for differentiation between post-menopausal women hip fracture and controls, and to compare results with standard bone densitometry. MATERIALS AND METHODS We used dual-energy X-ray absorptiometry (DXA) to measure the femoral bone mineral density (BMD) of 100 post-menopausal women (73.4 +/- 12.2), 50 of whom had a recent hip fracture. Local bone mineral distribution in the scanner-generated images was analyzed in the standard DXA-regions of interest (ROIs; femoral neck, the shaft, the trochanteric area; and the total hip) using an optimized, local topological parameter MF2D. Performance of topological analysis and BMD was tested by receiver-operator characteristic and discriminant analysis. RESULTS Area under the curve (AUC) for correct differentiation between patients with and without fractures by BMD in the different ROIs ranged from 0.64 to 0.71; AUC of regional density-pattern analysis varied between 0.79 and 0.84. Using multivariate statistical models, between 71% and 84% of patients were correctly identified as fracture/non-fracture cases by regional topological analysis, whereas BMD reached levels from 58% to 68%. CONCLUSION Our analysis indicates that identification of patients with hip fracture by regional evaluation of density patterns varies with anatomical location within the proximal femur. In our study population, performance of the novel parameter was superior to densitometry.
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Affiliation(s)
- H F Boehm
- Department of Radiology, Ludwig-Maximilians-Universitaet, Campus Downtown, Munich, Germany.
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Boehm HF, Lutz J, Körner M, Mutschler W, Reiser M, Pfeifer KJ. Using Radon transform of standard radiographs of the hip to differentiate between post-menopausal women with and without fracture of the proximal femur. Osteoporos Int 2009; 20:323-33. [PMID: 18560746 DOI: 10.1007/s00198-008-0663-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 05/09/2008] [Indexed: 11/25/2022]
Abstract
UNLABELLED Texture features based on the Radon transform were extracted from clinical radiographs of the hip in post-menopausal women. The novel algorithm allowed us to identify patients with fracture of the proximal femur and may provide an alternative to measuring bone mineral density in predicting the fracture-risk in osteoporosis, especially where densitometry is regionally unavailable. INTRODUCTION The aim of this study is to introduce an algorithm for differentiation between patients with and without fracture of the hip using parameters based on the Radon transform (RT) and applied to standard radiographs of the proximal femur and to compare the results with bone mineral density (BMD). METHODS The study comprised 50 post-menopausal women (78.6 +/- 11.5 years of age), including 25 patients with hip fracture and 25 age-matched controls. We obtained lumbar and femoral BMD and standard femoral radiographs. In the radiographs we analysed trabecular patterns of the hip in a region-of-interest of 57 x 29 mm using the RT. From the histogram-representation of the RT, we extracted several characteristic parameters. By ROC and discriminant-analysis, we assessed the statistical power of both methods. RESULTS For correct differentiation between fracture and non-fracture cases by femoral BMD, area-under-the-curve (AUC) was 0.78; AUC for the RT-based parameters ranged from 0.73 to 0.8. By combination of densitometric and textural information in a multivariate model the fracture status of 84% of subjects was predicted correctly, identification of fracture cases rose to 88%. CONCLUSION Identification of fracture patients by RT applied to femoral radiographs was feasible and seemed to have a discriminative potential comparable to that of standard densitometry. In the future, the new method may provide an alternative to DXA or in conjunction with conventional densitometry may enhance the detection of patients with elevated risk of hip fracture.
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Affiliation(s)
- H F Boehm
- Department of Radiology, University of Munich, Germany.
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Automated Classification of Breast Parenchymal Density: Topologic Analysis of X-Ray Attenuation Patterns Depicted with Digital Mammography. AJR Am J Roentgenol 2008; 191:W275-82. [DOI: 10.2214/ajr.07.3588] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Boehm HF, Horng A, Notohamiprodjo M, Eckstein F, Burklein D, Panteleon A, Lutz J, Reiser M. Prediction of the fracture load of whole proximal femur specimens by topological analysis of the mineral distribution in DXA-scan images. Bone 2008; 43:826-31. [PMID: 18723137 DOI: 10.1016/j.bone.2008.07.244] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 07/25/2008] [Accepted: 07/29/2008] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To evaluate scanner-generated images of hip specimens obtained from dual energy X-ray absorptiometry (DXA) by quantitative image analysis of bone mineral distribution in the standard regions of interest (ROI), to predict the ultimate mechanical strength, and to compare the predictive potential with standard densitometry. MATERIALS AND METHODS Femoral bone mineral density (BMD) of 100 hip specimens was obtained by DXA in the total hip, shaft, trochanteric, and neck ROI. Maximum compressive strength (MCS) of the specimens was measured in a mechanical loading device simulating a fall on the greater trochanter. The topology of bone mineral distribution in the scan images was evaluated by image processing methods based on the Minkowski functionals (MF) using the optimized topological parameter MF2D. Correlation and multivariate analysis were employed to assess the statistical potential of BMD and MF2D with respect to predict the mechanical strength of the femur specimens. RESULTS R2 for the correlation between load-to-failure and BMD varied between 0.73 and 0.79 (exponential curve fit, p<0.001), being highest in the trochanteric ROI. Correlation between load-to-failure of the specimens with the topological parameter MF2D ranged from R2 =0.8 to 0.91 (p<0.001). In a multivariate model combining the topological information from all ROIs, correlation with MCS rose to R2 =0.94. CONCLUSION The topological parameter MF2D can be employed to predict the mechanical strength of proximal femur specimens from DXA-generated images. Performance is superior to standard evaluation of DXA. In the future, the proposed image processing method may serve to improve the assessment of an individual's fracture risk.
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Affiliation(s)
- Holger F Boehm
- Department of Radiology, Ludwig-Maximilians-Universitaet, Munich, Germany.
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