Clinical utility of dual-energy vertebral assessment (DVA)

Ground truth generalizability affects performance of the artificial intelligence model in automated vertebral fracture detection on plain lateral radiographs of the spine

BACKGROUND CONTEXT

Computer-aided diagnosis with artificial intelligence (AI) has been used clinically, and ground truth generalizability is important for AI performance in medical image analyses. The AI model was trained on one specific group of older adults (aged≧60) has not yet been shown to work equally well in a younger adult group (aged 18-59).

PURPOSE

To compare the performance of the developed AI model with ensemble method trained with the ground truth for those aged 60 years or older in identifying vertebral fractures (VFs) on plain lateral radiographs of spine (PLRS) between younger and older adult populations.

STUDY DESIGN/SETTING

Retrospective analysis of PLRS in a single medical institution.

OUTCOME MEASURES

Accuracy, sensitivity, specificity, and interobserver reliability (kappa value) were used to compare diagnostic performance of the AI model and subspecialists' consensus between the two groups.

METHODS

Between January 2016 and December 2018, the ground truth of 941 patients (one PLRS per person) aged 60 years and older with 1101 VFs and 6358 normal vertebrae was used to set up the AI model. The framework of the developed AI model includes: object detection with You Only Look Once Version 3 (YOLOv3) at T0-L5 levels in the PLRS, data pre-preprocessing with image-size and quality processing, and AI ensemble model (ResNet34, DenseNet121, and DenseNet201) for identifying or grading VFs. The reported overall accuracy, sensitivity and specificity were 92%, 91% and 93%, respectively, and external validation was also performed. Thereafter, patients diagnosed as VFs and treated in our institution during October 2019 to August 2020 were the study group regardless of age. In total, 258 patients (339 VFs and 1725 normal vertebrae) in the older adult population (mean age 78±10.4; range, 60-106) were enrolled. In the younger adult population (mean age 36±9.43; range, 20-49), 106 patients (120 VFs and 728 normal vertebrae) were enrolled. After identification and grading of VFs based on the Genant method with consensus between two subspecialists', VFs in each PLRS with human labels were defined as the testing dataset. The corresponding CT or MRI scan was used for labeling in the PLRS. The bootstrap method was applied to the testing dataset.

RESULTS

The model for clinical application, Digital Imaging and Communications in Medicine (DICOM) format, is uploaded directly (available at: http://140.113.114.104/vght_demo/svf-model (grading) and http://140.113.114.104/vght demo/svf-model2 (labeling). Overall accuracy, sensitivity and specificity in the older adult population were 93.36% (95% CI 93.34%-93.38%), 88.97% (95% CI 88.59%-88.99%) and 94.26% (95% CI 94.23%-94.29%), respectively. Overall accuracy, sensitivity and specificity in the younger adult population were 93.75% (95% CI 93.7%-93.8%), 65.00% (95% CI 64.33%-65.67%) and 98.49% (95% CI 98.45%-98.52%), respectively. Accuracy reached 100% in VFs grading once the VFs were labeled accurately. The unique pattern of limbus-like VFs, 43 (35.8%) were investigated only in the younger adult population. If limbus-like VFs from the dataset were not included, the accuracy increased from 93.75% (95% CI 93.70%-93.80%) to 95.78% (95% CI 95.73%-95.82%), sensitivity increased from 65.00% (95% CI 64.33%-65.67%) to 70.13% (95% CI 68.98%-71.27%) and specificity remained unchanged at 98.49% (95% CI 98.45%-98.52%), respectively. The main causes of false negative results in older adults were patients' lung markings, diaphragm or bowel airs (37%, n=14) followed by type I fracture (29%, n=11). The main causes of false negatives in younger adults were limbus-like VFs (45%, n=19), followed by type I fracture (26%, n=11). The overall kappa between AI discrimination and subspecialists' consensus in the older and younger adult populations were 0.77 (95% CI, 0.733-0.805) and 0.72 (95% CI, 0.6524-0.80), respectively.

CONCLUSIONS

The developed VF-identifying AI ensemble model based on ground truth of older adults achieved better performance in identifying VFs in older adults and non-fractured thoracic and lumbar vertebrae in the younger adults. Different age distribution may have potential disease diversity and implicate the effect of ground truth generalizability on the AI model performance.

High prevalence of vertebral fractures in seizure patients with normal bone density receiving chronic anti-epileptic drugs

People with epilepsy who take certain medications are at risk for developing osteoporosis and fractures of the vertebrae that commonly go undiagnosed. By using technology available in a bone density scan, we observed at least one fracture in many subjects with bone density in the normal and osteopenic range.

PURPOSE/INTRODUCTION

Chronic use of antiepileptic drugs (AEDs), both enzyme-inducing (phenytoin, phenobarbital, carbamazepine, and primidone) and non-enzyme-inducing (i.e., valproate), is recognized as a cause of secondary osteoporosis. Vertebral compression fractures (VF) are the most common type of osteoporotic fractures and may confer an increased risk of future hip, wrist, and vertebral fractures. Vertebral compression fractures in the general population are frequently asymptomatic, and under-diagnosed. The purpose of this study is to describe the prevalence of VF in a cohort of male veterans with epilepsy on chronic AEDs.

METHODS

The cohort for this study consisted of 146 male veterans who carried a diagnosis of epilepsy and were chronic users of AEDs known to cause osteoporosis (phenobarbital, phenytoin, carbamazepine, primidone, and valproate). Chronic AED use was defined as receiving an AED for at least 2 years. Subjects were previously seen in the osteoporosis clinic and had been evaluated by a dual-energy X-Ray absormetry (DXA) instrument including morphometric studies following a standard vertebral fracture assessment (VFA) protocol during the same DXA imaging acquisition session.

RESULTS

The mean age was 63 years. Low bone mineral density defined as osteoporosis or osteopenia was observed in 29% and 43% respectively. We observed at least one VF in 41 % of the subjects who had normal BMD, 54% in the osteopenic range, and 75% in the osteoporotic range.

CONCLUSIONS

By performing a VFA in addition to standard bone densitometric studies, we disclosed a large prevalence of compression fractures in individuals with epilepsy chronically treated with AEDs who had BMDs in the normal and osteopenic ranges. The addition of VFA or other imaging methods to evaluate VF should be included in the evaluation of bone health in individuals with epilepsy receiving AEDs since it may modify treatment recommendations to prevent future osteoporotic fractures.

Can a Deep-learning Model for the Automated Detection of Vertebral Fractures Approach the Performance Level of Human Subspecialists?

BACKGROUND

Vertebral fractures are the most common osteoporotic fractures in older individuals. Recent studies suggest that the performance of artificial intelligence is equal to humans in detecting osteoporotic fractures, such as fractures of the hip, distal radius, and proximal humerus. However, whether artificial intelligence performs as well in the detection of vertebral fractures on plain lateral spine radiographs has not yet been reported.

QUESTIONS/PURPOSES

(1) What is the accuracy, sensitivity, specificity, and interobserver reliability (kappa value) of an artificial intelligence model in detecting vertebral fractures, based on Genant fracture grades, using plain lateral spine radiographs compared with values obtained by human observers? (2) Do patients' clinical data, including the anatomic location of the fracture (thoracic or lumbar spine), T-score on dual-energy x-ray absorptiometry, or fracture grade severity, affect the performance of an artificial intelligence model? (3) How does the artificial intelligence model perform on external validation?

METHODS

Between 2016 and 2018, 1019 patients older than 60 years were treated for vertebral fractures in our institution. Seventy-eight patients were excluded because of missing CT or MRI scans (24% [19]), poor image quality in plain lateral radiographs of spines (54% [42]), multiple myeloma (5% [4]), and prior spine instrumentation (17% [13]). The plain lateral radiographs of 941 patients (one radiograph per person), with a mean age of 76 ± 12 years, and 1101 vertebral fractures between T7 and L5 were retrospectively evaluated for training (n = 565), validating (n = 188), and testing (n = 188) of an artificial intelligence deep-learning model. The gold standard for diagnosis (ground truth) of a vertebral fracture is the interpretation of the CT or MRI reports by a spine surgeon and a radiologist independently. If there were any disagreements between human observers, the corresponding CT or MRI images would be rechecked by them together to reach a consensus. For the Genant classification, the injured vertebral body height was measured in the anterior, middle, and posterior third. Fractures were classified as Grade 1 (< 25%), Grade 2 (26% to 40%), or Grade 3 (> 40%). The framework of the artificial intelligence deep-learning model included object detection, data preprocessing of radiographs, and classification to detect vertebral fractures. Approximately 90 seconds was needed to complete the procedure and obtain the artificial intelligence model results when applied clinically. The accuracy, sensitivity, specificity, interobserver reliability (kappa value), receiver operating characteristic curve, and area under the curve (AUC) were analyzed. The bootstrapping method was applied to our testing dataset and external validation dataset. The accuracy, sensitivity, and specificity were used to investigate whether fracture anatomic location or T-score in dual-energy x-ray absorptiometry report affected the performance of the artificial intelligence model. The receiver operating characteristic curve and AUC were used to investigate the relationship between the performance of the artificial intelligence model and fracture grade. External validation with a similar age population and plain lateral radiographs from another medical institute was also performed to investigate the performance of the artificial intelligence model.

RESULTS

The artificial intelligence model with ensemble method demonstrated excellent accuracy (93% [773 of 830] of vertebrae), sensitivity (91% [129 of 141]), and specificity (93% [644 of 689]) for detecting vertebral fractures of the lumbar spine. The interobserver reliability (kappa value) of the artificial intelligence performance and human observers for thoracic and lumbar vertebrae were 0.72 (95% CI 0.65 to 0.80; p < 0.001) and 0.77 (95% CI 0.72 to 0.83; p < 0.001), respectively. The AUCs for Grades 1, 2, and 3 vertebral fractures were 0.919, 0.989, and 0.990, respectively. The artificial intelligence model with ensemble method demonstrated poorer performance for discriminating normal osteoporotic lumbar vertebrae, with a specificity of 91% (260 of 285) compared with nonosteoporotic lumbar vertebrae, with a specificity of 95% (222 of 234). There was a higher sensitivity 97% (60 of 62) for detecting osteoporotic (dual-energy x-ray absorptiometry T-score ≤ -2.5) lumbar vertebral fractures, implying easier detection, than for nonosteoporotic vertebral fractures (83% [39 of 47]). The artificial intelligence model also demonstrated better detection of lumbar vertebral fractures compared with detection of thoracic vertebral fractures based on the external dataset using various radiographic techniques. Based on the dataset for external validation, the overall accuracy, sensitivity, and specificity on bootstrapping method were 89%, 83%, and 95%, respectively.

CONCLUSION

The artificial intelligence model detected vertebral fractures on plain lateral radiographs with high accuracy, sensitivity, and specificity, especially for osteoporotic lumbar vertebral fractures (Genant Grades 2 and 3). The rapid reporting of results using this artificial intelligence model may improve the efficiency of diagnosing vertebral fractures. The testing model is available at http://140.113.114.104/vght_demo/corr/. One or multiple plain lateral radiographs of the spine in the Digital Imaging and Communications in Medicine format can be uploaded to see the performance of the artificial intelligence model.

LEVEL OF EVIDENCE

Level II, diagnostic study.

Vertebral fracture: epidemiology, impact and use of DXA vertebral fracture assessment in fracture liaison services

Vertebral fractures are independent risk factors for vertebral and nonvertebral fractures. Since vertebral fractures are often missed, the relatively new introduction of vertebral fracture assessment (VFA) for imaging of the lateral spine during DXA-measurement of the spine and hips may contribute to detect vertebral fractures. We advocate performing a VFA in all patients with a recent fracture visiting a fracture liaison service (FLS). Fracture liaison services (FLS) are important service models for delivering secondary fracture prevention for older adults presenting with a fragility fracture. While commonly age, clinical risk factors (including fracture site and number of prior fracture) and BMD play a crucial role in determining fracture risk and indications for treatment with antiosteoporosis medications, prevalent vertebral fractures usually remain undetected. However, vertebral fractures are important independent risk factors for future vertebral and nonvertebral fractures. A development of the DXA technology, vertebral fracture assessment (VFA), allows for assessment of the lateral spine during the regular DXA bone mineral density measurement of the lumbar spine and hips. Recent approaches to the stratification of antiosteoporosis medication type according to baseline fracture risk, and differences by age in the indication for treatment by prior fracture mean that additional information from VFA may influence initiation and type of treatment. Furthermore, knowledge of baseline vertebral fractures allows reliable definition of incident vertebral fracture events during treatment, which may modify the approach to therapy. In this manuscript, we will discuss the epidemiology and clinical significance of vertebral fractures, the different methods of detecting vertebral fractures, and the rationale for, and implications of, use of VFA routinely in FLS. • Vertebral fracture assessment is a tool available on modern DXA instruments and has proven ability to detect vertebral fractures, the majority of which occur without a fall and without the signs and symptoms of an acute fracture. • Most osteoporosis guidelines internationally suggest that treatment with antiosteoporosis medications should be considered for older individuals (e.g., 65 years +) with a recent low trauma fracture without the need for DXA. • Younger individuals postfracture may be risk-assessed on the basis of FRAX® probability including DXA and associated treatment thresholds. • Future fracture risk is markedly influenced by both site, number, severity, and recency of prior fracture; awareness of baseline vertebral fractures facilitates definition of true incident vertebral fracture events occurring during antiosteoporosis treatment. • Detection of previously clinically silent vertebral fractures, defining site of prior fracture, might alter treatment decisions in younger or older FLS patients, consistent with recent IOF-ESCEO guidance on baseline-risk-stratified therapy, and provides a reliable baseline from which to define new, potentially therapy-altering, vertebral fracture events.

Grade 1 Vertebral Fractures Identified by Densitometric Lateral Spine Imaging Predict Incident Major Osteoporotic Fracture Independently of Clinical Risk Factors and Bone Mineral Density in Older Women

Because prevalent vertebral fracture (VF) is a strong predictor of future fractures, they are important to identify in clinical practice as osteoporosis medications are effective and can be used to reduce fracture risk in postmenopausal women with VF. Lateral spine imaging (LSI) with dual-energy X-ray absorptiometry (DXA) can be used to diagnose VFs accurately but is not widespread in clinical practice. The prognostic value of grade 1 (20% to 25% compression) VFs diagnosed by LSI with DXA has been insufficiently studied. The aim of this study was to determine if grade 1 VF is associated with incident fracture in older women. Sahlgrenska University Hospital Prospective Evaluation of Risk of Bone Fractures (SUPERB) is a population-based study of 3028 older women from Gothenburg, Sweden. Included women were 75 to 80 years of age at baseline, answered questionnaires, and were scanned with DXA (Discovery A, Hologic, Waltham, MA, USA). LSI was used to diagnose VFs, which were classified using the Genant semiquantitative method. Cox regression models were used to estimate the association between VFs at baseline and X-ray-verified incident fractures, with adjustment for confounders. Women with a grade 1 VF (n = 264) or a grade 2-3 VF (n = 349) were compared with women without any fracture (n = 1482). During 3.6 years (median, interquartile range [IQR] 1.5 years) of follow-up, 260 women had any incident fracture and 213 a major osteoporotic fracture (MOF). Women with only grade 1 VF had increased risk of any fracture (hazard ratio [HR] = 1.67; 95% confidence interval [CI] 1.18-2.36) and MOF (HR = 1.86; 95% CI 1.28-2.72). For MOF, this association remained after adjustment for clinical risk factors and femoral neck bone mineral density (BMD). In conclusion, grade 1 VFs were associated with incident MOF, also after adjustment for clinical risk factors and BMD, indicating that all VF identified by DXA should be considered in the evaluation of fracture risk in older women. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research..

Vertebral fracture assessment (VFA) in patients over 50 years of age with a non-severe peripheral fracture

The prevalence of unknown vertebral fractures evaluated by systematic vertebral fracture assessment (VFA) was 21% in patients over 50 years of age who suffered from a recent low-trauma non-severe peripheral fracture. The outcome of VFA resulted in changes in the management of osteoporosis.

INTRODUCTION

The aim of this study was to evaluate the utility of VFA in detecting vertebral fractures (VFs) in patients over 50 years of age, who suffered from a recent low-trauma non-severe peripheral fracture.

METHODS

This was an observational, single-center, cross-sectional study conducted in patients over 50 years of age, who presented a recent low-trauma non-severe peripheral fracture and were identified by the Fracture Liaison Service (FLS) of Amiens University Hospital between December 2017 and March 2019. VFA was interpreted by two trained rheumatologists providing a consensual reading using Genant semi-quantitative assessment.

RESULTS

Of the 359 eligible patients, 114 patients (31.8%) were included (mean age 65.6 ± 8.4 years; 89.5% female). Twenty-four patients (21%) had one or more VF diagnosed by VFA. The total number of VF diagnosed by VFA was 30: 20 VF (66.7%) grade 1, 7 VF (23.3%) grade 2, and 3 VF (10%) grade 3. Among the 24 patients with at least one prevalent VF diagnosed by VFA, 18 patients had an osteoporosis medication adaptation after the VFA results (16 osteoporosis medication initiation and 2 treatment intensification), and 6 patients would have had an osteoporosis medication even without the VFA results (66.7% versus 33.3% respectively, p < 0.001). Of the 51 patients receiving an osteoporosis medication after DXA and VFA, 18 patients (35.3%) had a change in the management of osteoporosis after knowing the outcome of VFA. All the VFs diagnosed by VFA were unknown before. We did not evidence any threshold (age, T-score, height loss) below which no VF was detected.

CONCLUSIONS

Our study demonstrates the usefulness of systematic VFA to detect prevalent VF in patients over 50 years of age who suffer from a recent non-severe peripheral fracture.

Diagnosis of osteoporotic vertebral fractures in children

Osteoporosis is a generalised disorder of the skeleton with reduced bone density and abnormal bone architecture. It increases bone fragility and renders the individual susceptible to fractures. Fractures of the vertebrae are common osteoporotic fractures. Vertebral fractures may result in scoliosis or kyphosis and, because they may be clinically silent, it is imperative that vertebral fractures are diagnosed in children accurately and at an early stage, so the necessary medical care can be implemented. Traditionally, diagnosis of osteoporotic vertebral fractures has been from lateral spine radiographs; however, a small number of studies have shown that dual energy x-ray absorptiometry is comparable to radiographs for identifying vertebral fractures in children, while allowing reduced radiation exposure. The diagnosis of vertebral fractures from dual energy x-ray absorptiometry is termed vertebral fracture assessment. Existing scoring systems for vertebral fracture assessment in adults have been assessed for use in children, but there is no standardisation and observer reliability is variable. This literature review suggests the need for a semiautomated tool that (compared to the subjective and semiquantitative methods available) will allow more reliable and precise detection of vertebral fractures in children.

Diagnosis of vertebral deformities on chest CT and DXA compared to routine lateral thoracic spine X-ray

X-ray, CT and DXA enable diagnosis of vertebral deformities. For this study, level of agreement of vertebral deformity diagnosis was analysed. We showed that especially on subject level, these imaging techniques could be used for opportunistic screening of vertebral deformities in COPD patients.

INTRODUCTION

X-ray and CT are frequently used for pulmonary evaluation in patients with chronic obstructive pulmonary disease (COPD) and also enable to diagnose vertebral deformities together with dual-energy X-ray absorptiometry (DXA) imaging. The aim of this research was to study the level of agreement of these imaging modalities for diagnosis of vertebral deformities from T4 to L1.

METHODS

Eighty-seven subjects (mean age of 65; 50 males; 57 COPD patients) who had X-ray, chest CT (CCT) and DXA were included. Evaluable vertebrae were scored twice using SpineAnalyzer™ software. ICCs and kappas were calculated to examine intra-observer variability. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the receiver operating characteristic curve (AUROC) were calculated to compare vertebral deformities diagnosed on the different imaging modalities.

RESULTS

ICCs for height measurements were excellent (> 0.94). Kappas were good to excellent (0.64-0.77). At vertebral level, the AUROC was 0.85 for CCT vs. X-ray, 0.74 for DXA vs. X-ray and 0.77 for DXA vs. CCT. Sensitivity (51%-73%) and PPV (57%-70%) were fair to good; specificity and NPV were excellent (≥ 96%). At subject level, the AUROC values were comparable.

CONCLUSIONS

Reproducibility of height measurements of vertebrae is excellent with all three imaging modalities. On subject level, diagnostic performance of CT (PPV 79-82%; NPV 90-93%), and to a slightly lesser extend of DXA (PPV 73-77%; NPV 80-89%), indicates that these imaging techniques could be used for opportunistic screening of vertebral deformities in COPD patients.

ACR Appropriateness Criteria® Osteoporosis and Bone Mineral Density

Osteoporosis is a considerable public health risk, with 50% of women and 20% of men >50 years of age experiencing fracture, with mortality rates of 20% within the first year. Dual x-ray absorptiometry (DXA) is the primary diagnostic modality by which to screen women >65 years of age and men >70 years of age for osteoporosis. In postmenopausal women <65 years of age with additional risk factors for fracture, DXA is recommended. Some patients with bone mineral density above the threshold for treatment may qualify for treatment on the basis of vertebral body fractures detected through a vertebral fracture assessment scan, a lateral spine equivalent generated from a commercial DXA machine. Quantitative CT is useful in patients with advanced degenerative bony changes in their spines. New technologies such as trabecular bone score represent an emerging role for qualitative assessment of bone in clinical practice. It is critical that both radiologists and referring providers consider osteoporosis in their patients, thereby reducing substantial morbidity, mortality, and cost to the health care system. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The Prevalence of Vertebral Fractures Is Associated With Reduced Hip Bone Density and Inferior Peripheral Appendicular Volumetric Bone Density and Structure in Older Women

Vertebral fractures (VFs) are among the most severe and prevalent osteoporotic fractures. Their association with bone microstructure have been investigated in several retrospective case-control studies with spine radiography for diagnosis of VF. The aim of this population-based cross-sectional study of 1027 women aged 75 to 80 years was to investigate if prevalent VF, identified by vertebral fracture assessment (VFA) by dual-energy X-ray absorptiometry (DXA), was associated with appendicular volumetric bone density, structure, and bone material strength index (BMSi), independently of hip areal bone mineral density (aBMD). aBMD was measured using DXA (Discovery; Hologic); BMSi with microindentation (Osteoprobe); and bone geometry, volumetric BMD, and microstructure with high-resolution peripheral quantitative computed tomography (HRpQCT) (XtremeCT; Scanco Medical AG). aBMD was lower (spine 3.2%, total hip [TH] 3.8%) at all sites in women with VF, but tibia BMSi did not differ significantly compared to women without VF. In multivariable adjusted logistic regression models, radius trabecular bone volume fraction and tibia cortical area (odds ratio [OR] 1.26; 95% confidence interval [CI], [1.06 to 1.49]; and OR 1.27 [95% CI, 1.08 to 1.49], respectively) were associated with VF prevalence, whereas BMSi and cortical porosity were not. The risk of having one, two, or more than two VFs was increased 1.27 (95% CI, 1.04 to 1.54), 1.83 (95% CI, 1.28 to 2.61), and 1.78 (95% CI, 1.03 to 3.09) times, respectively, for each SD decrease in TH aBMD. When including either cortical area, trabecular bone volume fraction or TBS in the model together with TH aBMD and covariates, only TH aBMD remained independently associated with presence of any VF. In conclusion, TH aBMD was consistently associated with prevalent VFA-verified VF, whereas neither trabecular bone volume fraction, cortical area, cortical porosity, nor BMSi were independently associated with VF in older women. © 2017 American Society for Bone and Mineral Research.

Vertebral fractures and their association with health-related quality of life, back pain and physical function in older women

Studies investigating prevalent vertebral fracture (VF) diagnosed using densitometry-based VF assessment (VFA) and associations with physical function, assessed by performance-based measures, are lacking. In this population-based study of 1027 older women, we found that prevalent VF, identified by VFA, was associated with inferior physical health, back pain and inferior physical function.

PURPOSE

Several studies have investigated the associations between health-related quality of life (HRQL) and back pain with prevalent VF, detected by spine radiographs, but just a few have been population-based and have used vertebral fracture assessment (VFA) for diagnosing VF. The aims of this study were to investigate associations between prevalent VF, detected by VFA, with HRQL, back pain and physical function, and investigate if also mild VFs were associated with these clinical parameters.

METHODS

One thousand twenty-seven women aged 75-80 years participated in this population-based cross-sectional study. VF was identified by VFA using dual-energy X-ray absorptiometry. HRQL was assessed by SF-12, back pain during the past 12 months using a questionnaire, and physical function was tested with one leg standing (OLS), Timed Up and Go (TUG), walking speed, 30-s chair stand test and maximum grip strength.

RESULTS

Physical health (Physical Component Summary, PCS), derived from SF-12, was worse (43.5 ± 11.3 vs. 46.2 ± 10.5, p < 0.001) and back pain more frequent in women with any VF than in women without (69.0 vs. 59.9%, p = 0.008). PCS and physical function (OLS, 30-s chair stand test), were significantly worse for mild VF compared to no VF (43.8 ± 10.9 vs. 46.2 ± 10.5, p < 0.001, 12.7 ± 9.9 vs. 15.3 ± 10.4 s, p = 0.038, 10.7 ± 3.2 vs. 11.4 ± 3.4 times, p = 0.021, respectively). In multivariable adjusted linear regression models, VF prevalence was associated with PCS (β = - 0.079, p = 0.007), TUG (β = 0.067, p = 0.021), walking speed (β = - 0.071, p = 0.009) and 30-s chair stand test (β = - 0.075, p = 0.012).

CONCLUSIONS

In conclusion, prevalent VF, diagnosed by VFA, was associated with inferior physical health, back pain and inferior physical function, indicating VFA is useful for diagnosing clinically relevant vertebral fractures. Also, mild VF was associated with inferior physical health and inferior physical function.

Vertebral fracture assessment: Enhancing the diagnosis, prevention, and treatment of osteoporosis

Osteoporosis is a highly prevalent condition, resulting in significant morbidity and mortality. Nevertheless, it is frequently untreated. Vertebral fractures often do not come to clinical attention, yet, their presence is diagnostic of osteoporosis, helps to predict the risk of future fractures, and may alter the choice of pharmacotherapy. The addition of lateral spine imaging technology to the densitometer, for vertebral fracture assessment (VFA), represented a major advancement in the ability to diagnose vertebral fractures and osteoporosis. VFA is an under-utilized and highly effective imaging tool to enhance osteoporosis detection and fracture prevention. Several factors make VFA an ideal technology to evaluate for vertebral fractures. These include: the ability to obtain the image at the same time the bone density is done, with significantly lower radiation exposure than with spine radiography, and at a lower cost. This review provides an overview of the clinical significance of identifying vertebral fractures, the origins of the VFA, its clinical indications, a review of the methods used to diagnose vertebral fracture, an overview on interpreting the VFA, and the strengths and limitations of this technique.

Value and potential limitations of vertebral fracture assessment (VFA) compared to conventional spine radiography: experience from a fracture liaison service (FLS) and a meta-analysis

We evaluated the value of VFA in the identification of vertebral fractures using a retrospective study and a meta-analysis. Performance of VFA was adequate in the meta-analysis although this was not demonstrated in our centre. We recommend checking the performance of VFA tools before exclusively relying on this tool.

INTRODUCTION

Vertebral fractures are traditionally diagnosed using conventional radiographs of the spine. Vertebral fracture assessment (VFA) has been advocated as an alternative tool in the diagnosis of these fractures.

METHODS

We conducted a retrospective study as well as a systematic review and a meta-analysis to evaluate the performance of VFA compared to conventional spinal radiography in patients who had sustained a fracture and thus at risk for osteoporosis. A risk of bias analysis was also performed.

RESULTS

The diagnostic study included 542 patients (25% male) with fractures. The sensitivity of low-radiation VFA to detect a patient with a vertebral fracture ≥ Genant grade 2 was 0.77 and its specificity 0.80. Two hundred ninety-seven (55%) patients had ≥1 and 135(25%) ≥3 unevaluable vertebrae. The systematic review identified 16 studies including a total of 3238 subjects (19% male) with a mean age range of 45 to 74 years. Seven studies had a low risk of bias and 9 had an intermediate risk, mainly due to not consecutively including patients. The pooled sensitivity of VFA to detect a patient with a vertebral fracture ≥Genant grade 2 was 0.84 (95% CI, 0.72-0.92) and specificity 0.90 (95% CI, 0.84-0.94).

CONCLUSIONS

Our findings from the meta-analysis suggest an adequate performance of VFA for the detection of vertebral fractures. However, we could not demonstrate these findings in our center, especially the specificity. Our data advocate caution with exclusively relying on VFA in the assessment of vertebral fractures without identifying performance and potential limitations of the technique.

Spine fracture prevalence in a nationally representative sample of US women and men aged ≥40 years: results from the National Health and Nutrition Examination Survey (NHANES) 2013-2014

Spine fracture prevalence is similar in men and women, increasing from <5 % in those <60 to 11 % in those 70-79 and 18 % in those ≥80 years. Prevalence was higher with age, lower bone mineral density (BMD), and in those meeting criteria for spine imaging. Most subjects with spine fractures were unaware of them.

INTRODUCTION

Spine fractures have substantial medical significance but are seldom recognized. This study collected contemporary nationally representative spine fracture prevalence data.

METHODS

Cross-sectional analysis of 3330 US adults aged ≥40 years participating in NHANES 2013-2014 with evaluable Vertebral Fracture Assessment (VFA). VFA was graded by semiquantitative measurement. BMD and an osteoporosis questionnaire were collected.

RESULTS

Overall spine fracture prevalence was 5.4 % and similar in men and women. Prevalence increased with age from <5 % in those <60 to 11 % in those 70-79 and 18 % in those ≥80 years. Fractures were more common in non-Hispanic whites and in people with lower body mass index and BMD. Among subjects with spine fracture, 26 % met BMD criteria for osteoporosis. Prevalence was higher in subjects who met National Osteoporosis Foundation (NOF) criteria for spine imaging (14 vs 4.7 %, P < 0.001). Only 8 % of people with a spine fracture diagnosed by VFA had a self-reported fracture, and among those who self-reported a spine fracture, only 21 % were diagnosed with fracture by VFA.

CONCLUSION

Spine fracture prevalence is similar in women and men and increases with age and lower BMD, although most subjects with spine fracture do not meet BMD criteria for osteoporosis. Since most (>90 %) individuals were unaware of their spine fractures, lateral spine imaging is needed to identify these women and men. Spine fracture prevalence was threefold higher in individuals meeting NOF criteria for spine imaging (∼1 in 7 undergoing VFA). Identifying spine fractures as part of comprehensive risk assessment may improve clinical decision making.

Diagnostic accuracy of DXA compared to conventional spine radiographs for the detection of vertebral fractures in children

OBJECTIVES

In children, radiography is performed to diagnose vertebral fractures and dual energy x-ray absorptiometry (DXA) to assess bone density. In adults, DXA assesses both. We aimed to establish whether DXA can replace spine radiographs in assessment of paediatric vertebral fractures.

METHODS

Prospectively, lateral spine radiographs and lateral spine DXA of 250 children performed on the same day were independently scored by three radiologists using the simplified algorithm-based qualitative technique and blinded to results of the other modality. Consensus radiograph read and second read of 100 random images were performed. Diagnostic accuracy, inter/intraobserver and intermodality agreements, patient/carer experience and radiation dose were assessed.

RESULTS

Average sensitivity and specificity (95 % confidence interval) in diagnosing one or more vertebral fractures requiring treatment was 70 % (58-82 %) and 97 % (94-100 %) respectively for DXA and 74 % (55-93 %) and 96 % (95-98 %) for radiographs. Fleiss' kappa for interobserver and average kappa for intraobserver reliability were 0.371 and 0.631 respectively for DXA and 0.418 and 0.621 for radiographs. Average effective dose was 41.9 μSv for DXA and 232.7 μSv for radiographs. Image quality was similar.

CONCLUSION

Given comparable image quality and non-inferior diagnostic accuracy, lateral spine DXA should replace conventional radiographs for assessment of vertebral fractures in children.

KEY POINTS

• Vertebral fracture diagnostic accuracy of lateral spine DXA is non-inferior to radiographs. • The rate of unreadable vertebrae for DXA is lower than for radiographs. • Effective dose of DXA is significantly lower than radiographs. • Children prefer DXA to radiographs. • Given the above, DXA should replace radiographs for paediatric vertebral fracture assessment.

Vertebral fracture assessment by DXA is inferior to X-ray in clinical severe osteoporosis

Spine fractures are diagnosed by X-ray or vertebral fracture assessment (VFA) by dual-energy X-ray absorptiometry (DXA) scanning. The use of VFA evaluation by DXA is still debated. We demonstrate that VFA is inferior relative to X-ray in visualizing vertebrae properly in the upper spine and therefore with a reduced diagnostic performance in detecting fractures.

INTRODUCTION

Vertebral fracture assessment (VFA) by DXA has been evaluated for many years, and its use in clinical practice is still debated. In a cross-sectional setting, we aimed to compare VFA with traditional radiography in vertebral fracture (VF) diagnosis in severe osteoporotic patient.

METHODS

A total of 207 patients referred to the outpatient clinic for teriparatide treatment were screened, out of whom 35 (16.9 %) severe osteoporotic patients were identified (mean age 67.5 ± 11.3 years and median T-score -3.2 interquartile range (IQR) (-1.9 to -3.7). VF diagnosis was performed independently using VFA and X-ray in accordance with the semiquantitative (SQ) approach. The same technician performed the primary interpretation on both sets of images, after which a radiologist and an endocrinologist reviewed the evaluation for a conclusive judgement.

RESULTS

In total, 180 radiographic fractures were detected, corresponding to 5.1 fractures per individual. Using VFA, 18.5 % of vertebrae were considered unreadable, compared to 2.0 % on X-ray. The accuracy of VFA in VF detection using X-ray as a reference resulted in sensitivity and specificity of 75.5 and 86.7 %, respectively. Sensitivity decreased from the lumbar to thoracic level. Nevertheless, VFA only identified fractures consistently between Th11 and L3.

CONCLUSION

Our data, based on a severe osteoporotic population, demonstrate that VFA is inferior relative to X-ray in visualizing vertebrae properly in the upper spine, resulting in vertebrae not being assessable for analysis and a reduced diagnostic performance in detecting fractures. Improvements in DXA techniques are needed for it to be comparable with X-ray in VF diagnosis.

A systematic review of diagnostic accuracy of vertebral fracture assessment (VFA) in postmenopausal women and elderly men

This systematic review was performed to compare the diagnostic accuracy of vertebral fracture assessment (VFA) with that of spinal radiography for identification of vertebral fractures (VFs). VFA appeared to have moderate sensitivity and high specificity for detecting VFs when compared with spinal radiography.

INTRODUCTION

VFs are recognized as the hallmark of osteoporosis, and a previous VF increases the risk of a future fracture. Therefore, the timely detection of VFs is important for prevention of further fractures. This systematic review examined the diagnostic accuracy of VFA using dual X-ray absorptiometry (DXA) to identify VFs.

METHODS

We searched for potentially relevant studies using electronic databases, including Ovid-Medline, Ovid-EMBASE, Cochrane library, and four Korean databases, from their inception to May 2013. We compared the diagnostic accuracy of VFA with that of spinal radiography for detection of VFs by analyzing the sensitivity and specificity using a 2 × 2 contingency table. Subgroup analyses were also performed on studies with a low risk of bias and applicability.

RESULTS

Twelve studies were analyzed for the diagnostic accuracy of VFA. The sensitivity and specificity were 0.70-0.93 and 0.95-1.00, respectively, analyzed on a per-vertebra basis, and 0.65-1.00 and 0.74-1.00 on a per-patient basis. The sensitivity and specificity of five studies in subgroups with a low risk of bias in the intervention test were 0.70-0.84 and 0.96-0.99, respectively. In studies with a low risk of bias in the patient selection, those based on a per-vertebra basis in three studies were 0.70-0.93 and 0.96-1.00, respectively.

CONCLUSIONS

VFA had moderate sensitivity and high specificity for detecting VF when compared with spinal radiography. However, the present findings are insufficient to assess whether spinal radiography should be replaced by VFA.

Accuracy of densitometric vertebral fracture assessment when performed by DXA technicians--a cross-sectional, multiobserver study

Six dual-energy X-ray absorptiometry (DXA) technicians reviewed lateral images of the spine for deformed vertebrae. The images were acquired with a DXA scanner in 235 patients referred for osteoporosis assessment. The outcome was compared to findings on spinal radiographs assessed by two radiologists. Three DXA technicians performed acceptable or better in identifying patients with fractured vertebrae.

INTRODUCTION

This is the first study to evaluate the accuracy of vertebral fracture assessment (VFA) when used by DXA technicians as a triage test to select patients with deformed vertebrae for spinal radiographs.

METHODS

Lateral single-energy scans and radiographs of the thoracolumbar spine (T4-L4) were acquired in 235 patients aged 65 years or more referred for osteoporosis assessment. Six DXA technicians evaluated lateral scans using dedicated software. The DXA technicians were trained to identify deformed vertebrae, but they did not assess the aetiology of deformity. Two radiologists evaluated the radiographs and their consensus evaluation served as the reference test for vertebral fracture. The main outcome was sensitivity and specificity of the DXA technicians' identification of patients with one or more grade II-III deformities according to Genant's classification.

RESULTS

The proportion of patients with one or more grade II-III vertebral fractures was 0.35. Sensitivity ranged from 0.61 to 0.83 and specificity ranged from 0.78 to 0.95 across the DXA technicians. In patients with grade II-III deformities on VFA, the mean probability of one or more grade II-III fractures was 0.74 (range 0.66-0.86). Conversely, in patients without such deformities, the mean probability of grade II-III fractures was 0.14 (range 0.10-0.18). Accuracy was lower for grade I-III deformities for all the DXA technicians.

CONCLUSION

Three of six DXA technicians achieved acceptable or better accuracy when using VFA to triage patients with grade II-III vertebral deformities for spinal radiographs. Heterogeneity between DXA technicians appears to be due to differences in subjective thresholds. VFA triage by DXA technicians to identify patients with grade II-III fractures is feasible.

The Vertebral Fracture Cascade: Etiology and Clinical Implications

A vertebral fracture is a marker of bone fragility and is associated with a downward spiral of recurrent fractures known as the vertebral fracture cascade. Etiology of this unfortunate cascade includes bone and muscle loss from immobility, changes in spinal mechanics causing increased loading on adjacent vertebrae, and the development of an increased thoracic kyphosis (hyperkyphosis [HK]). Degenerative disc disease, common in osteoporotic patients, can also cause HK. HK of any etiology has been associated with decreased thoracic extensor muscle strength, unstable gait, increased body sway, decreased physical and pulmonary functions, chronic pain, and increased spinal loads contributing to the vertebral fracture cascade. Preventing this downward spiral requires a multidisciplinary approach that includes early identification, consideration of pharmacologic treatment, early mobilization of the fracture patient, appropriate exercise, and back protection. Exercise should include weight-bearing and muscle-strengthening activities, but caution is needed to avoid undue stress on the back. Physical therapy can be particularly helpful by teaching the patient how to safely perform daily activities and can assist the patient in establishing a safe exercise program that avoids flexion but promotes back extension and weight-bearing activities. Hopefully, these measures will decrease pain, prevent falls, improve posture, prevent additional bone and muscle loss, and potentially abort the devastating downward spiral of the vertebral fracture cascade.

A critical appraisal of vertebral fracture assessment in paediatrics

PURPOSE

There is a need to improve our understanding of the clinical utility of vertebral fracture assessment (VFA) in paediatrics and this requires a thorough evaluation of its readability, reproducibility, and accuracy for identifying VF.

METHODS

VFA was performed independently by two observers, in 165 children and adolescents with a median age of 13.4 years (range, 3.6, 18). In 20 of these subjects, VFA was compared to lateral vertebral morphometry assessment on lateral spine X-ray (LVM).

RESULTS

1528 (84%) of the vertebrae were adequately visualised by both observers for VFA. Interobserver agreement in vertebral readability was 94% (kappa, 0.73 [95% CI, 0.68, 0.73]). 93% of the non-readable vertebrae were located between T6 and T9. Interobserver agreement per-vertebra for the presence of VF was 99% (kappa, 0.85 [95% CI, 0.79, 0.91]). Interobserver agreement per-subject was 91% (kappa, 0.78 [95% CI, 0.66, 0.87]). Per-vertebra agreement between LVM and VFA was 95% (kappa 0.79 [95% CI, 0.62, 0.92]) and per-subject agreement was 95% (kappa, 0.88 [95% CI, 0.58, 1.0]). Accepting LVM as the gold standard, VFA had a positive predictive value (PPV) of 90% and a negative predictive value (NPV) of 95% in per-vertebra analysis and a PPV of 100% and NPV of 93% in per-subject analysis.

CONCLUSION

VFA reaches an excellent level of agreement between observers and a high level of accuracy in identifying VF in a paediatric population. The readability of vertebrae at the mid thoracic region is suboptimal and interpretation at this level should be exercised with caution.

The discriminative ability of FRAX, the WHO algorithm, to identify women with prevalent asymptomatic vertebral fractures: a cross-sectional study

BACKGROUND

A Moroccan model for the FRAX tool to determine the absolute risk of osteoporotic fracture at 10 years has been established recently. The study aimed to assess the discriminative capacity of FRAX in identifying women with prevalent asymptomatic vertebral fractures (VFs).

METHODS

We enrolled in this cross-sectional study 908 post-menopausal women with a mean age of 60.9 years ± 7.7 (50 to 91) with no prior known diagnosis of osteoporosis. Subjects were recruited from asymptomatic women selected from the general population. Lateral VFA images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genantsemiquantitative (SQ) approach and morphometry. We calculated the absolute risk of major fracture and hip fracture with and without bone mineral density (BMD)using the FRAX website.The overall discriminative value of the different risk scores was assessed by calculating the areas under the ROC curve (AUC).

RESULTS

VFA images showed that 179 of the participants (19.7%) had at least one grade 2/3 VF. The group of women with VFs had a statistically significant higher FRAX scores for major and hip fractures with and without BMD, and lower weight, height, and lumbar spine and hip BMD and T-scores than those without a VFA-identified VF. The AUC ROC of FRAX for major fracture without BMD was 0.757 (CI 95%; 0.718-0.797) and 0.736 (CI 95%; 0.695-0.777) with BMD, being 0.756 (CI 95%; 0.716-0.796) and 0.747 (CI 95%; 0.709-0.785), respectively for FRAX hip fracture without and with BMD. The AUC ROC of lumbar spine T-score and femoral neck T-score were 0.660 (CI 95%; 0.611-0.708) and 0.707 (CI 95%; 0.664-0.751) respectively.

CONCLUSION

In asymptomatic post-menopausal women, the FRAX risk for major fracture without BMD had a better discriminative capacity in identifying the women with prevalent VFs than lumbar spine and femoral neck T-scores suggesting its usefulness in identifying women in whom VFA could be indicated.

Prediction models of prevalent radiographic vertebral fractures among older men

No studies have compared how well different prediction models discriminate older men who have a radiographic prevalent vertebral fracture (PVFx) from those who do not. We used area under receiver operating characteristic curves and a net reclassification index to compare how well regression-derived prediction models and nonregression prediction tools identify PVFx among men age ≥65 yr with femoral neck T-score of -1.0 or less enrolled in the Osteoporotic Fractures in Men Study. The area under receiver operating characteristic for a model with age, bone mineral density, and historical height loss (HHL) was 0.682 compared with 0.692 for a complex model with age, bone mineral density, HHL, prior non-spine fracture, body mass index, back pain, grip strength, smoking, and glucocorticoid use (p values for difference in 5 bootstrapped samples 0.14-0.92). This complex model, using a cutpoint prevalence of 5%, correctly reclassified only a net 5.7% (p = 0.13) of men as having or not having a PVFx compared with a simple criteria list (age ≥ 80 yr, HHL >4 cm, or glucocorticoid use). In conclusion, simple criteria identify older men with PVFx and regression-based models. Future research to identify additional risk factors that more accurately identify older men with PVFx is needed.

Vertebral fracture assessment by dual X-ray absorptiometry: a valid tool to detect vertebral fractures in community-dwelling older adults in a population-based survey

OBJECTIVE

Vertebral fractures are associated with higher morbidity and mortality. Since 70% of vertebral fractures are clinically silent, a radiologic image of the spine has to be acquired for the diagnosis. The aim of this study was to compare the performance of Vertebral Fracture Assessment (VFA) by dual x-ray absorptiometry (DXA) with radiographs to identify vertebral fractures in community-dwelling older adults.

METHODS

A total of 429 older adults (ages ≥65 years) were enrolled in this cohort. VFA by DXA measurements were evaluated by 2 expert rheumatologists by consensus, and spine radiographs were analyzed according to the semiquantitative method by an expert radiologist. The correlation between VFA and spine radiographs to identify vertebral fractures was analyzed by kappa scores.

RESULTS

The prevalence of vertebral fractures in VFA and radiographs was 29.1% and 29.4%, respectively (P = 0.99). The frequency of unavailable vertebrae was significantly lower in spinal radiographs than in VFA (0.9% and 5.6%, respectively; P < 0.001), particularly in T4-T6. According to VFA, 5,013 vertebrae (96%) were identified as normal and 144 (2.7%) had grade 1, 58 (1.1%) had grade 2, and 12 (0.2%) had grade 3 fractures. The sensitivity of VFA was 72.9% and the specificity was 99.1% to identify vertebral fractures. The sensitivity increased to 92% and the specificity increased to 99.9% when excluding grade 1 deformities. A good correlation between VFA and radiographs (κ = 0.74) was observed, and the exclusion of grade 1 resulted in even better agreement (κ = 0.84).

CONCLUSION

In community-dwelling older adults, VFA and radiographs had comparable performances in identifying vertebral fractures, particularly if mild deformities are excluded. Therefore, this methodology is a feasible and promising alternative to improve the management of patients with a high risk of osteoporotic fractures.

Diagnostic performance of vertebral fracture assessment by the lunar iDXA scanner compared to conventional radiography

The purpose of this study was to evaluate the diagnostic performance of vertebral fracture assessment (VFA) using the Lunar iDXA scanner. Conventional spinal radiographs and images acquired by dual-energy X-ray absorptiometry (DXA) of 350 subjects (269 females, 81 males) were evaluated by two different readers. We visualized 4,476/4,550 (98.4 %) vertebrae from T4 to L4 on VFA images compared to 4,535/4,550 (99.7 %) on radiographs. Among the visualized vertebrae, 205/4,535 (4.5 %) and 190/4,476 (4.2 %) were identified as nonfracture deformities by reading of radiographs and VFA, respectively. Vertebral fractures (VFs) were 231 in 126 patients and 228 in 125 patients by semiquantitative assessment of radiographs (SQ-Rx) and by VFA, respectively. There was excellent agreement between the two techniques and high diagnostic performance of VFA both on a per-vertebra basis (k score = 0.984, 95 % CI 0.972-0.996, sensitivity 98.68 %, specificity 99.91 %, PPV 98.25 %, NPV 99.93 %) and on a per-patient basis (k score = 0.957, 95 % CI 0.925-0.988, sensitivity 96.83 %, specificity 98.66 %, PPV 97.60 %, NPV 98.22 %). In older patients (≥65 years) affected by moderate or severe osteoarthritis, SQ-Rx and VFA identified 96 VFs and 95 versus 90 vertebral deformities, respectively. This study demonstrates that most vertebrae are evaluable using the iDXA scanner, with improved VFA diagnostic performance even in discriminating mild VFs from vertebral deformities. Therefore, VFA may be appropriate as an alternative to conventional radiography in patients at high risk of VF who are undergoing DXA bone densitometry and in the follow-up of osteoporotic patients on treatment.

Intrarater reliability of dual-energy X-ray absorptiometry-based measures of vertebral height in postmenopausal women

The primary purpose was to estimate intrarater reliability of vertebral body height (VH) measures in postmenopausal women based on duplicate analyses of vertebral fracture assessment (VFA) images. The secondary purpose was to determine the consistency in classification of vertebral deformity on duplicate analyses. Thirty-two VFA were randomly selected from a database of 464 scans acquired in postmenopausal women using dual-energy X-ray absorptiometry (Discovery A; Hologic Inc., Waltham, MA). Visible endplates were marked on each image on 2 occasions (4 wk apart) by a single rater; the semiautomated software derived measures of anterior, middle, and posterior VH and classified severity of vertebral deformity. Intrarater reliability was assessed using the intraclass correlation coefficient (with 95% confidence interval [CI]) when ≥ 22 VFA could be analyzed. Reliability of grading deformity of 267 vertebrae was assessed using Cohen's unweighted kappa (with 95% CI). Reliability of anterior, middle, and posterior height measures from T8 to L4 was 0.85 and greater except for T8 anterior VH and T9 posterior VH (0.76 [0.43, 0.90] and 0.62 [0.15, 0.83], respectively). Chance-corrected agreement for 4 grades of vertebral deformity was 0.48 (0.30, 0.66) and for 2 categories (normal/mild and moderate/severe) was 0.70 (50, 0.90). Intrarater reliability was acceptable for VH measures from T10 to L4. Reliability in grading severity of deformity was improved by classifying as <25% deformity (nonfracture) and as >25% deformity (fracture).

The importance of morphometric radiographic vertebral assessment for the detection of patients who need pharmacological treatment of osteoporosis among postmenopausal diabetic Korean women

Many diabetic patients with vertebral fractures remain undiagnosed and untreated. We found that more than two-thirds of osteoporotic diabetic women could not be identified for pharmacological treatment according to the NOF guidelines if without radiographic vertebral assessment. This study shows the importance of radiographic vertebral assessment for identifying patients who need treatment for osteoporosis in diabetic women.

INTRODUCTION

Diagnosis of vertebral fracture (VF) is important for identifying patients who need pharmacologic therapy for osteoporosis. However, many patients with vertebral fractures remain undiagnosed and untreated. This study evaluated the number of patients with VFs who would be unrecognized as candidates for osteoporosis treatments according to the National Osteoporosis Foundation (NOF) Clinician’s Guidelines to the Treatment of Osteoporosis, among postmenopausal diabetic Korean women without spinal imaging.

METHODS

A total of 873 postmenopausal diabetic women were enrolled. Lateral plain radiographs of the thoracolumbar spine and total hip BMD were obtained. The Fracture Risk Assessment Tool (FRAX®) probability was computed using the algorithm available online at http://www.shef.ac.uk/FRAX (South Korea version). The subjects with and without VFs were classified into candidates for osteoporosis treatment [Tx+by NOF] and not candidates for osteoporosis treatment [Tx−by NOF] according to the NOF pharmacologic treatment guidelines, regardless of the presence of VFs.

RESULTS

Forty-six percent of postmenopausal diabetic womenhad morphometric VFs. Among the subjects with morphometric VFs, only 2% of the patients had previously diagnosed VFs by medical doctors. In addition, 73.6% of the patients with VFs were not included in the [Tx+by NOF] group, given the assumption of no radiographic diagnosis of VFs.

CONCLUSIONS

With regard to increased risk of VFs in postmenopausal Korean women with type 2 diabetes mellitus, radiographic vertebral assessment would be useful for the clinical identification of osteoporosis and fractures.

Vertebral morphometry by dual-energy X-ray absorptiometry (DXA) for osteoporotic vertebral fractures assessment (VFA)

PURPOSE

This study was done to evaluate the diagnostic accuracy of dual-energy X-ray absorptiometry (DXA) compared with conventional radiography for identifying vertebral fractures.

MATERIALS AND METHODS

A total of 930 postmenopausal women underwent conventional radiography and DXA imaging of the spine. The images were evaluated by two expert skeletal radiologists using the semiquantitative (SQ) method for conventional radiography and the morphometric vertebral fracture assessment (VFA) for DXA.

RESULTS

The SQ method for radiography (SQ-Rx) analysed 99.1% of vertebrae, identifying 442 vertebral fractures; VFA analysed 97.5% vertebrae, detecting 420 vertebral fractures. Agreement between SQ-Rx and VFA reached 98.76%, and the κ-score was 0.96 [95% confidence interval (CI), 0.95-0.98]. Assessing the grading of vertebral fractures, agreement reached 97.5% and the κ-score was 0.841 (95% CI, 0.821-0.891). Considering SQ-Rx method as "gold standard", VFA had a sensitivity of 97.85 % and a specificity of 99.81%. The negative (NPV) and positive (PPV) predictive value for VFA were 99.83 % and 98.15%, respectively. Fractures were identified in 251 (27 %) and 242 (26 %) of patients on SQ-Rx and VFA, respectively. On a per-patient basis, the agreement between the two methods was 97% and the κ-score was 0.95 (95% CI, 0.920-0.968). The diagnostic parameters for VFA were 97.23% sensitivity, 98.86% specificity, 97.60% PPV and 98.84% NPV.

CONCLUSIONS

This study demonstrated that VFA with DXA may reach a high level of accuracy for diagnosing vertebral fractures, suggesting that VFA should be introduced in the screening of individuals with a risk of osteoporosis and in the follow-up of osteoporotic patients receiving treatment.

Uncertainties in the prevention and treatment of glucocorticoid-induced osteoporosis

Much knowledge has accrued since the 2001 American College of Rheumatology (ACR) guidelines were published to assist clinicians in the prevention and treatment of glucocorticoid-induced osteoporosis (GIO). Therefore, the ACR undertook a comprehensive effort to review the literature and update the GIO guidelines [Grossman JM, Gordon R, Ranganath VK, et al. American College of Rheumatology 2010 recommendations for the prevention and treatment of glucocorticoid-induced osteoporosis. Arthritis Care Res (Hoboken). 2010;62:1515-1526]. Herein, we review the new guidelines for JBMR readers, highlighting the changes introduced by the 2010 publication. We discuss several patient scenarios for which the new treatment guidelines do not apply, or for which our committee interprets existing literature differently and suggests an alternative approach.

The Prevalence of Undetected Vertebral Fracture in Patients with Back Pain by Dual-Energy X-ray Absorptiometry (DXA) of the Lateral Thoracic and Lumbar Spine

STUDY DESIGN

This is a prospective study.

PURPOSE

This study is conducted to determine the prevalence of unrecognized vertebral fracture (VF) in patients who present with back pain.

OVERVIEW OF LITERATURE

VF is often unrecognized, and significantly increases the risk of further fractures. Unfortunately, the patients at a high risk for VF usually do not receive adequate therapy to reduce the fracture risk.

METHODS

This is a prospective study of 344 patients who presented with back pain from April 2008 to May 2009. The patients underwent dual-energy X-ray absorptiometry (DXA) evaluation and vertebral fracture assessment from T4 to L4 using a hologic densitometer.

RESULTS

Three hundred forty four of 386 patients who presented with back pain were included. Forty two patients were excluded because of a prior history of VF or the lack of written consent. Most of the patients were female (95.3%). The mean age of the patients was 58.21 ± 11.74 years. According to the World Health Organization definition (based on the T-score), 13.4% of the patients had normal lumbar spine bone mineral density (BMD). 27.9% of them were osteopenic and 58.7% were osteoporotic. The overall prevalence of VF, as established by lateral vertebral assessment, was 39% (n = 134). Moreover, 62.6% (n = 84) of the patients with VF had more than one fracture and 64.1% (n = 86) of them had Grade 2 or 3 fracture.

CONCLUSIONS

We recommend performing not only DXA scanning for BMD evaluation, but also VFA by DXA in old patients with back pain.

Radiology of osteoporosis

Bone densitometric studies have shown that osteoporosis is a result of prolonged, slow bone loss and that the pattern of loss is different for trabecular and cortical bone. Structurally-insufficient osteoporotic bone is predisposed to fractures. Among the clinically manifest osteoporotic fractures, distal radius leads the list, followed by hip, spine, and proximal humerus. This article examines the use of conventional radiography as well as other imaging-based modalities for the evaluation of osteoporosis and associated fractures in the axial and appendicular skeleton.

Evaluation of vertebral fracture assessment by dual X-ray absorptiometry in a multicenter setting

SUMMARY

The utility of vertebral fracture assessment (VFA) by DXA to detect prevalent vertebral fracture in a multicenter setting was investigated by comparison to conventional radiography. While limited by lower image quality, overall performance of VFA was good but had a tendency to miss mild prevalent fractures.

INTRODUCTION

In osteoporosis clinical trials standardized spine radiographs are used to detect vertebral fractures as a study endpoint. Lateral spine imaging with dual X-ray absorptiometry (DXA) scanners, known as vertebral fracture assessment (VFA) by DXA, presents a potential alternative to conventional radiography with lower radiation dose and greater patient convenience.

METHODS

We investigated in a multicenter setting the ability of VFA to detect fractures in comparison with conventional radiography. The study examined 203 postmenopausal women who had imaging of the spine by DXA and radiography. Three radiologists experienced in vertebral fracture assessment independently read the VFA scans and radiographs using the Genant semiquantitative method on two occasions.

CONCLUSIONS

Analyzing the data from all readable vertebrae, the kappa statistic, sensitivity, and specificity ranged from 0.64-0.77, 0.65-0.84, and 0.97-0.98, respectively. Considering only moderate and severe fractures improved the kappa statistic (0.80-0.91) and sensitivity (0.70-0.86). While image quality of VFA is inferior to radiography, the detection of vertebral fractures using visual scoring is feasible. However, VFA underperformed due to unreadable vertebrae and reduced sensitivity for mild fractures. Nevertheless, VFA correctly identified most moderate and severe vertebral fractures. Despite this limitation, VFA by DXA provides an important tool for clinical research.

Morphometric vertebral fractures of the lower thoracic and lumbar spine, physical function and quality of life in men

The epidemiology and sequelae of morphometric vertebral fracture (MVF) are poorly documented. We found that MVFs of the lower thoracic and lumbar spine were associated with poor quality of life and impaired physical function in men. We recommend that morphometric X-ray absorptiometry be included in routine requests for bone densitometry.

INTRODUCTION

Vertebral fractures are sentinel events for osteoporosis. We aimed to compare quality of life and physical function in men with and without MVF.

METHODS

Using morphometric X-ray absorptiometry (T10-L4), MVFs were identified in a random sample of men aged 20-93 years. Moderate and severe wedge, biconcave or compression deformities (>25% reduction in any vertebral height) were classified as MVFs.

RESULTS

Of 1,147 men, MVFs were identified in 64. No MVFs were detected for men in their twenties. Prevalence was 1.5% for 30-39 years, 1.4% 40-49 years, 3.2% 50-59 years, 4.7% 60-69 years, 10.0% 70-79 years and 14.6% 80+ years. Among 555 men aged 60+ years, those with MVFs were twice as likely to have quality of life scores in the lowest tertile (age-adjusted OR = 2.35, 95%CI 1.24-4.45). MVFs were associated with lower mean age-adjusted physical activity scores [11.3 (95%CI 9.0-13.8) vs 14.0 (13.2-14.9), P = 0.04] and longer mean age-adjusted 'Up-&-Go' times [9.5 (8.9, 10.1) vs 8.9 (8.8, 9.1) s, P = 0.06].

CONCLUSION

Despite most men being unaware of their condition, MVFs were associated with poor quality of life and impaired physical function. We recommend that morphometric X-ray absorptiometry be included in routine requests for bone densitometry because detection of MVFs has important implications for osteoporosis management in men.

Vertebral Fracture Assessment: the 2007 ISCD Official Positions

Vertebral fracture assessment (VFA) is an established, low radiation method for detection of prevalent vertebral fractures. Vertebral fractures are usually not recognized clinically at the time of their occurrence, but their presence indicates a substantial risk for subsequent fractures independent of bone mineral density. Significant evidence supporting VFA use for many post-menopausal women and older men has accumulated since the last ISCD Official Position Statement on VFA was published. The International Society for Clinical Densitometry considered the following issues at the 2007 Position Development Conference: (1) What are appropriate indications for Vertebral Fracture Assessment; (2) What is the most appropriate method of vertebral fracture detection with VFA; (3) What is the sensitivity and specificity for detection of vertebral fractures with this method; (4) When should additional spine imaging be performed following a VFA; and (5) What are the reporting obligations for those interpreting VFA images?

Routine versus targeted vertebral fracture assessment for the detection of vertebral fractures

Fracture risk is underestimated in women with unknown vertebral fractures. Using VFA, we compared two screening methods: targeted (6,388 women) and routine (2,176 women). Routine screening detected fractures in 20%. Targeted screening only required 5% attending for DXA to undergo VFA but only detected 9.6% of women with fractures.

INTRODUCTION

BMD alone underestimates fracture risk in women with unknown vertebral fractures. We report the results of routine vertebral fracture assessment (VFA) screening and compare with targeted screening.

METHOD

Our centre initially targeted VFA at women with reasons to suspect a vertebral fracture. Later we changed to routine VFA screening for all women over 65. We retrospectively compare each screening method's ability to detect vertebral fractures.

RESULTS

Six thousand three hundred and eighty-eight women over 65 underwent DXA during the period of targeted VFA and 2,176 during routine VFA. Routine VFA detected 420 (20.0%) women with fracture. Most vertebral fractures (56.2%) occurred in women with osteopenia. Routine VFA would be expected to alter the management of 1 in 6 osteopenic women. Targeted VFA was performed in 332 (5.2%) women detecting 122 (1.9%) women with fractures. It was estimated that targeted VFA only detected 9.6% of women with a vertebral fracture. Targeted VFA failed to detect fractures in 18.1% of the population attending for DXA and in 29% of those with osteoporosis.

CONCLUSION

Routine VFA detects vertebral fractures in 20% of women over 65. Targeted VFA greatly reduces the number of VFAs performed but only detects a minority of the women with vertebral fractures.

High prevalence of morphometric vertebral deformities in patients with inflammatory bowel disease

BACKGROUND

Earlier studies have documented that the prevalence of decreased bone mineral density (BMD) is elevated in patients with inflammatory bowel disease. The objective of this study was to investigate the prevalence of vertebral deformities in inflammatory bowel disease patients and their relation with BMD and bone turnover.

METHODS

One hundred and nine patients with Crohn's disease (CD) and 72 with ulcerative colitis (UC) (age 44.5+/-14.2 years) were studied. BMD of the hip (by dual X-ray absorptiometry) was measured and a lateral single energy densitometry of the spine for assessment of vertebral deformities was performed. Serum markers of bone resorption (carboxy-terminal cross-linked telopeptide of type I collagen) and formation (procollagen type I amino-terminal propeptide) were measured, and determinants of prevalent vertebral deformities were assessed using logistic regression analysis.

RESULTS

Vertebral deformities were found in 25% of both CD and UC patients. Comparing patients with and without vertebral deformities, no significant difference was found between Z-scores and T-scores of BMD, or levels of serum carboxy-terminal cross-linked telopeptide of type I collagen and serum procollagen type I amino-terminal propeptide. Using logistic regression analysis the only determinant of any morphometric vertebral deformity was sex. The presence of multiple vertebral deformities was associated with older age and glucocorticoid use.

CONCLUSION

The prevalence of morphometric vertebral deformities is high in CD and UC. Male sex, but neither disease activity, bone turnover markers, clinical risk factors, nor BMD predicted their presence. The determinants for having more than one vertebral deformity were age and glucocorticoid use. This implies that in addition to screening for low BMD, morphometric assessment of vertebral deformities is warranted in CD and UC.

Algorithm-based qualitative and semiquantitative identification of prevalent vertebral fracture: agreement between different readers, imaging modalities, and diagnostic approaches

We compared SQ and ABQ diagnosis of VF imaged by radiography and X-ray absorptiometry. Mild ABQ VF had stronger associations with osteoporosis than mild SQ VF. Interobserver agreement (radiographic diagnosis) was better for ABQ.

INTRODUCTION

Vertebral fracture (VF) assessment from images acquired by X-ray absorptiometry (VFA) is often based on a semiquantitative approach (SQ); prevalent VF is identified if vertebral height appears reduced by >20%. Algorithm-based qualitative definition of osteoporotic VF (ABQ) requires evidence of endplate depression, and there is no threshold for reduction in vertebral height. The aims of this study were to (1) compare the prevalence of VFs; (2) compare the characteristics of women with and without VFs; (3) compare interobserver agreement; and (4) compare agreement between methods and imaging modalities for ABQ and SQ definitions of VFs.

MATERIALS AND METHODS

Spine radiographs and absorptiometry images for 203 elderly women were assessed using ABQ (readers ABQ-1 and ABQ-2). These readings were compared with SQ assessments (readers SQ-1 and SQ-2) of the same images performed in a previous study. Agreement between readers and methods was assessed by kappa (kappa) statistics.

RESULTS

The prevalence of VF was 15-18% (radiography) and 12-24% (VFA) for ABQ and SQ, respectively. Women with ABQ or SQ fractures were older and had lower BMD than those without fracture (p < 0.01). Mild ABQ (but not SQ) VF was associated with low BMD. Kappa scores for interobserver agreement for radiography and VFA, respectively, were as follows: ABQ, kappa = 0.74 (95% CI, 0.60, 0.87) and 0.65 (95% CI, 0.48, 0.81); SQ, kappa = 0.53 (95% CI, 0.46, 0.60) and 0.51 (95% CI, 0.44, 0.58). For agreement between ABQ-1 and SQ-1, kappa = 0.55 (95% CI, 0.39, 0.72) for radiography and 0.41 (95% CI, 0.25, 0.58 for VFA.

CONCLUSIONS

The prevalence of radiographic VF identified by ABQ and SQ was similar, but on VFA was 50% higher for SQ. Mild ABQ VF was associated with low BMD. Interobserver agreement for radiographic diagnosis was significantly better for ABQ than for SQ. Agreement between ABQ and SQ was moderate.

Comparison of densitometric and radiographic vertebral fracture assessment using the algorithm-based qualitative (ABQ) method in postmenopausal women at low and high risk of fracture

Using ABQ diagnosis, the sensitivity to detect VF of densitometric versus radiographic assessment in 755 postmenopausal women was 71-81% and specificity was 97%. Misdiagnosis was influenced by image quality and was more common for mild deformities.

INTRODUCTION

Using densitometric vertebral fracture assessment (VFA), prevalent fractures are identified when vertebral height appears reduced by >or=20%. However, this approach does not discriminate between osteoporotic vertebral fracture (VF) and nonosteoporotic deformity, which increases the false-positive rate. Algorithm-based qualitative diagnosis (ABQ) focuses on vertebral endplate fracture to exclude these deformities but has not been applied in VFA. We wished to determine whether densitometric image quality is adequate for ABQ assessment. Our aims were to (1) calculate agreement between VFA and radiography using ABQ to identify prevalent VF and (2) identify the primary reasons for any discordant diagnosis.

METHODS

Radiographic and densitometric spine images for postmenopausal women at low risk (LR; n = 459) and high risk (HR; n = 298) of VF were assessed using ABQ. Agreement between imaging modalities for VF diagnosis was assessed by kappa statistics using ABQ radiographic readings as the gold standard.

RESULTS

The prevalence of VF was 11-29% (radiography) and 9-26% (VFA) in the LR and HR groups, respectively. Agreement between imaging modalities was good or very good (kappa = 0.62-0.81 in the LR and HR populations). The sensitivity to detect women with VF by VFA was 71% and 84% in the LR and HR populations, respectively, and specificity was 97%. Fifty-two (77%) and 60 (61%) of vertebrae misclassified by VFA in the LR and HR populations were mild fractures and 37 (54%) and 62 (63%) were wedge fractures. One third of fractures missed by VFA were related to poor or unreadable image quality (n = 27 and 28 vertebrae in the LR and HR populations, respectively).

CONCLUSIONS

There was good agreement between VFA and radiography using ABQ to identify prevalent VF in women at LR or HR of osteoporotic VF. Vertebrae misclassified by VFA were primarily mild fractures or deformities, and two thirds of all fractures missed by VFA were related to poor or unreadable image quality.

The relationship of an Asian-specific screening tool for osteoporosis to vertebral deformity and osteoporosis

An Asian-specific screening tool for osteoporosis, the so-called OSTA index, was devised and is likely to be helpful in determining which postmenopausal women need bone mineral density (BMD) measurement. Besides BMD, prevalent vertebral fracture is a strong risk factor for future fractures. However, the relationship of the OSTA index to prevalent vertebral fractures is currently unknown. In this study, we evaluated the performance of the OSTA index in elderly Thai women and assessed the relationship of the index to prevalent vertebral deformities. Subjects consisted of 741 healthy Thai elderly women. BMD was measured by DEXA and T-score <or=2.5 SD is defined as osteoporosis. Prevalent vertebral deformities were determined by morphometric X-ray absorptiometry. OSTA index >-1 is classified as having low risk of osteoporosis, -1 to -4 as intermediate risk and, <-4 as high risk. Data were expressed as mean +/- SD. The mean age and body weight of subjects were 67 +/- 4.8 years and 57.8 +/- 8.7 kg, respectively. The area under the ROC curve for OSTA index to identify osteoporosis at femoral neck and lumbar spine was 0.80 and 0.72, respectively. Femoral neck osteoporosis was found in 40.4%, 6.3%, and 2.4% of subjects with high-risk, intermediate-risk, and low-risk OSTA indexes, respectively. With regard to vertebral deformities, the area under the ROC curve relating OSTA index to vertebral deformities was 0.70 (P < 0.001). The prevalence of vertebral deformities in according to the OSTA index was 19.2% in the high-risk, 7.9% in the intermediate-risk, and 2.8% in the low-risk group. We concluded that the OSTA index can be of assistance in the selection of postmenopausal women for BMD measurement. In addition, this index may be helpful in the identification of postmenopausal women with vertebral deformity and those who need antifracture treatments.

An evaluation of densitometric vertebral fracture assessment in men

The utility of, and potential indications for, densitometric vertebral fracture assessment were evaluated in 1,168 men. A bimodal fracture distribution was observed, identifying fractures in 17% of men with no fracture history. Osteopenia or height loss of > or = 2.5'' may be indications for VFA in men.

INTRODUCTION

Densitometric vertebral fracture assessment (VFA) is an excellent means to detect unappreciated vertebral fractures in women. However, little evaluation of VFA in men has been performed. This study evaluated VFA utility and explored potential VFA indications in men.

METHODS

The study cohort consists of a population of 1,168 men (mean age, weight and BMI of 69.1 years, 188.8 pounds and 28.1 kg/m(2), respectively) referred for clinically indicated bone mineral density (BMD) measurement at the Wm. S. Middleton VAMC. Lateral VFA images and scans of the lumbar spine, proximal femur and non-dominant radius, were obtained by two technologists using a GE Healthcare Lunar Prodigy densitometer. Vertebral fractures were defined using the Genant visual semi-quantitative approach.

RESULTS

Seventy-eight percent of vertebrae from T4-L5 and 93% from T8-L5 were adequately visualized on VFA. Vertebral fractures were detected in 32% (374/1,168) of these men. A bimodal distribution was observed with fractures being most common in the mid-thoracic spine and at the thoraco-lumbar junction. As would be expected, the prevalence of VFA-detected fractures increased with age and as BMD declined. Fracture prevalence did not increase until a historical height loss of > or = 6.4 cm (2.5 inches) was reported. VFA-identified fractures were present in 17% of men who had no history of fracture. Furthermore, in men with densitometric osteopenia, no historical fracture and absence of glucocorticoid use (n = 158), vertebral fractures were detected in 18%.

CONCLUSION

VFA allows evaluation of the majority of vertebral bodies in men and identifies a substantial number of individuals with previously unappreciated fracture. Additionally, a more stringent height loss requirement, perhaps 2.5 inches or more, or densitometric osteopenia (low bone mineral density by DXA), may be appropriate as indications for performance of VFA in men.

Vertebral Fracture Assessment by dual-energy X-ray absorptiometry: insurance coverage issues in the United States. A White Paper of the International Society for Clinical Densitometry

Clinical trial data and fracture risk prediction models unequivocally demonstrate the utility of identifying prevalent vertebral fractures to predict future fractures of all types. Knowledge of prevalent vertebral fractures can alter patient management decisions and result in initiation of therapy to reduce fracture risk in some patients who would not otherwise be treated. Cost-benefit analysis demonstrates that identifying and treating patients with vertebral fractures, even those with a densitometric classification of osteopenia, is cost effective. Vertebral fractures can be readily identified in the office setting using standard radiography or Vertebral Fracture Assessment (VFA), a software addition to a central dual-energy X-ray absorptiometry (DXA) machine. In the United States, VFA was assigned a Current Procedural Terminology (CPT) code in January 2005. Nevertheless, coverage of VFA has not been uniformly embraced by Medicare carriers, companies that contract with the federal government to administer Medicare coverage and process claims for a region of the United States. Unlike DXA, for which uniform national coverage of qualified Medicare beneficiaries is mandated by the Balanced Budget Act of 1997, VFA coverage policies are determined by the local Medicare carriers. Third-party insurers are also variable in their coverage of VFA. This International Society for Clinical Densitometry (ISCD) White Paper documents the role of VFA in the evaluation and treatment of women with postmenopausal osteoporosis and compares it with standard spine radiography. Arguments used by some Medicare carriers and insurers to deny coverage of VFA in the United States are analyzed and critiqued. For health care providers within the United States, this White Paper may serve as a resource to respond to insurers who deny coverage of VFA. For health care providers regardless of their country, this article underscores the value of VFA as an alternative to spine radiography in the evaluation and management of postmenopausal women with suspected osteoporosis.

Enhanced prediction of fracture risk combining vertebral fracture status and BMD

Prevalent vertebral fractures are associated with increased fracture risk, but the magnitude of this effect across a range of BMD T-scores has not been quantified. In this analysis, for any given BMD T-score, incident fracture risk varied up to twelve fold when information regarding prevalent radiographic vertebral fracture status was considered.

BACKGROUND

Clinical fracture risk evaluation of older women usually includes assessment of bone mineral density (BMD) but often not vertebral fracture status. In this analysis, we quantified the impact of vertebral fracture burden on two year fracture risk across a range of BMD T-scores.

METHODS

Data were from 2,651 postmenopausal women who were assigned to the placebo groups of the Fracture Prevention Trial (median observation 21 months) and the Multiple Outcomes of Raloxifene Evaluation Trial (MORE; observation 2 years). Using the Genant visual semiquantitative criteria, we defined prevalent vertebral fracture status as: a) presence or absence of fracture; b) fracture number; c) maximum semi-quantitative (SQ) score (normal=0, mild fracture=1, moderate fracture=2, severe fracture=3); and d) spinal deformity index (SDI) score (sum of SQ scores of T4 to L4 vertebrae). Incident fractures over two years were identified via lateral spine radiographs and outside the spine by questioning of patients and review of radiographs or radiographic reports.

RESULTS

Femoral neck BMD T-score provided significant information regarding fracture risk. Across the range of T-scores, vertebral fracture status provided additional prognostic information. The risk increased with increasing number and severity of prevalent vertebral fractures and SDI, a summary measure of spine fracture burden. Across a range of BMD values, prevalent spine fracture burden as assessed by SDI increased the risk of incident vertebral fractures by up to 12-fold, nonvertebral fractures by about twofold, and any fractures by up to sevenfold.

CONCLUSIONS

These findings indicate that at any given BMD T-score, the risk of incident vertebral, non-vertebral, and any fracture depended heavily on prevalent radiographic vertebral fracture status. Assessment of vertebral fracture status, in addition to BMD, provides practical and relevant clinical information to aid in predicting fracture risk in postmenopausal women.

Risk factors for prevalent vertebral fractures in black and white female densitometry patients

This cross-sectional study compared risk factors for prevalent vertebral fractures (diagnosed using densitometric spine image Vertebral Fracture Assessment [VFA]) in 176 black and 345 white women recruited during their clinical bone mineral density (BMD) testing at the University of Chicago Hospitals. We used logistic regression to assess the association of prevalent vertebral fractures and risk factors (age, height loss, history of nonvertebral fractures, BMD, and use of corticosteroids). The prevalence of vertebral fractures was 21% for both races. All risk factors of interest were significantly associated with vertebral fractures in white women. Among black women, only age and corticosteroid use were found to be significant predictors of presence of vertebral fracture(s). In women without history of corticosteroid use, the probability of having vertebral fracture(s) given age was lower (p=0.02) in black subjects. In 77 patients with a history of corticosteroid use, the probability of having vertebral fracture(s) was higher in black than in white women after adjustment for age (p=0.045), BMD (p=0.045), or cumulative corticosteroid dose (p=0.08). Fewer black women were prescribed pharmacologic therapy for osteoporosis, regardless of their BMD level and corticosteroid use. We conclude that use of corticosteroids may be associated with relatively greater vertebral fracture risk in blacks than in whites.

Clinical review: Clinical applications of vertebral fracture assessment by dual-energy x-ray absorptiometry

CONTEXT

Vertebral fracture (VF) is the most common type of fragility fracture, yet most VFs are not clinically apparent. VFs are associated with a significant increase in morbidity, mortality, and risk of future fracture. Many patients with VFs do not have T-scores classified as osteoporosis. Knowledge of VFs may change diagnostic classification, estimation of future fracture risk, and clinical management. VF assessment (VFA) by dual-energy x-ray absorptiometry is a method for imaging the spine to diagnose VFs.

EVIDENCE ACQUISITION

Background information and medical evidence on the technology and clinical applications of VFA was acquired by electronic searching of PubMed for appropriate terms that included vertebral fracture, imaging, diagnosis, dual-energy x-ray absorptiometry, and cost effectiveness. Matches with the highest levels of medical evidence were selected for review, recognizing that the new and evolving nature of the field required inclusion of some material that relied partly on expert opinion.

EVIDENCE SYNTHESIS

The sensitivity and specificity of VFA compare favorably with spine radiographs in the ability to diagnose grade 2 and 3 VFs. VFA involves less radiation, lower cost, and often greater patient convenience than spine radiography. Cost effectiveness modeling suggests that imaging of the spine in selected patients provides essential diagnostic and therapeutic information at a nominal cost. Patients with T-scores that are classified as low bone mass (osteopenia) who are selected for pharmacological therapy based on the presence of a VF benefit by reduction in fracture risk. Guidelines for the clinical application of VFA have been developed by the International Society for Clinical Densitometry.

CONCLUSIONS

VFA is a technology for diagnosing VFs that may alter diagnostic classification, improve fracture risk stratification, and identify patients likely to benefit from pharmacological therapy who otherwise might not be treated.

Radiographic texture analysis of densitometer-generated calcaneus images differentiates postmenopausal women with and without fractures

INTRODUCTION

Bone fragility is determined by bone mass, measured as bone mineral density (BMD), and by trabecular structure, which cannot be easily measured using currently available noninvasive methods. In previous studies, radiographic texture analysis (RTA) performed on the radiographic images of the spine, proximal femur, and os calcis differentiated subjects with and without osteoporotic fractures. The present cross-sectional study was undertaken to determine whether such differentiation could also be made using high-resolution os calcis images obtained on a peripheral densitometer.

METHODS

In 170 postmenopausal women (42 with and 128 without prevalent vertebral fractures) who had no secondary causes of osteoporosis and were not receiving treatment for osteoporosis, BMD of the lumbar spine, proximal femur, and os calcis was measured using dual energy x-ray absorptiometry. Vertebral fractures were diagnosed on densitometric spine images. RTA, including Fourier-based and fractal analyses, was performed on densitometric images of os calcis.

RESULTS

BMD at all three sites and all texture features was significantly different in subjects with and without fractures, with the most significant differences observed for the femoral neck and total hip measurements and for the RTA feature Minkowski fractal (p<0.001). In univariate logistic regression analysis, Minkowski fractal predicted the presence of vertebral fractures as well as femoral neck BMD (p<0.001). In multivariate logistic regression analysis, both femoral neck BMD and Minkowski fractal yielded significant predictive effects (p=0.001), and when age was added to the model, the effect of RTA remained significant (p=0.002), suggesting that RTA reflects an aspect of bone fragility that is not captured by age or BMD. Finally, when RTA was compared in 42 fracture patients and 42 nonfracture patients matched for age and BMD, the RTA features were significantly different between the groups (p=0.003 to p=0.04), although BMD and age were not.

CONCLUSION

This study suggests that RTA of densitometer-generated calcaneus images provides an estimate of bone fragility independent of and complementary to BMD measurement and age.

Detection of abdominal aortic calcification with lateral spine imaging using DXA

Radiographic abdominal aortic calcification (AAC) is associated with incident cardiovascular disease and mortality independent of other risk factors. Lateral spine imaging using dual-energy X-ray absorptiometry (DXA) is now available to detect prevalent vertebral fracture (called vertebral fracture assessment), but its potential utility to detect radiographic AAC has not been investigated. Fifty-seven of 205 women age 65 or older who had participated in a prior study of the detection of prevalent vertebral fracture with lateral DXA had technically adequate radiographs and lateral DXA images to assess AAC. Two readers scored both the radiographic and lateral DXA images for AAC using a previously validated 24-point scale, blinded to both of each other's readings and also to their own readings on the other technology. The agreement between radiograph and lateral DXA AAC scores was very good (intra-class correlation coefficient [ICC] of 0.81 (95% confidence interval [CI]: 0.66-0.90) for reader 1 and 0.82 (95% CI: 0.69-0.90) for reader 2). The ICC between the two reader's AAC scores on radiographs was 0.92 (95% CI: 0.88-0.95) and on lateral DXA images was 0.89 (95% CI: 0.80-0.94). Lateral spine imaging with DXA shows very good agreement with standard radiography in the detection of AAC. Lateral imaging of the spine with DXA intended to detect vertebral fracture is a promising technology for the simultaneous assessment of a risk factor for cardiovascular disease incidence and death.

Addition of right lateral decubitus positioning improves vertebral visualization with VFA in selected patients

Densitometric vertebral fracture assessment (VFA) allows detection of clinically unappreciated vertebral fracture. However, vertebral visualization using VFA can be suboptimal. In such individuals, alternative spine positioning may enhance visualization. Consistent with this, we observed that reversal of positioning (right lateral decubitus rather than standard left lateral decubitus, subsequently referred to as "reverse" positioning) improved visualization in patients with suboptimal vertebral visualization. This report describes 33 such individuals (i.e., 30 men and 3 women); their mean age and their lowest T-score (L1-L4 spine, proximal femur or 0.3 radius) was 69.9 yr and 2.2, respectively. All images were acquired using a GE Healthcare Lunar Prodigy densitometer (GE Healthcare, Madison, WI). Reverse VFA increased the number of visualized vertebrae in 82% of these patients (27 of 33; p<0.0001). Specifically, only 62% of vertebrae from T4-L5 were visualized using the standard left lateral position. Addition of either full or partial reverse VFA increased (p<0.0001) the number of visualized vertebrae to 83% (384 of 462). In this cohort, reverse positioning allowed detection of 4 additional vertebral fractures, including two in patients without previously identified fractures. We conclude that in selected patients with suboptimal vertebral visualization on VFA, addition of reverse positioning improves visualization and may enhance vertebral fracture detection.