Michael M Ward

National Institute of Arthritis and Musculoskeletal and Skin Diseases, Maryland, United States

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Publications (121)674.36 Total impact

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    ABSTRACT: Syndesmophytes in AS typically grow slowly, but it is not known whether growth is uniform among syndesmophytes in the same intervertebral disc space (IDS) or among different IDSs in the same patient or if growth is heterogeneous. We examined the dynamics of syndesmophyte growth over 24 months using CT, with the main aim of determining if syndesmophytes in the same IDS or the same patient grow at similar rates.
    Rheumatology (Oxford, England) 11/2014; · 4.24 Impact Factor
  • Michael M. Ward, Lori C. Guthrie, Maria I. Alba
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    ABSTRACT: Objective: The patient global assessment (PGA) is intended to provide an integrated summary of all symptoms of arthritis, but it is not clear which disease features most impact patients' assessments of changes in their overall status. We investigated what aspects of rheumatoid arthritis (RA) activity correlated best with prospectively measured changes in the PGA, and with patients' retrospective judgments of improvement.Methods: We studied 250 patients with active RA in a prospective longitudinal study. Disease activity measures were collected before and after treatment escalation. Prospectively measured changes in PGA and patients' judgments of improvement or worsening at the follow-up visit were tested for correlations with changes in patient-reported measures of symptoms and functioning, joint counts, and laboratory tests.Results: Patients improved during the study, with the mean (± standard deviation) PGA decreasing from 55.6 ± 25.2 to 37.6 ± 24.0. At the follow-up visit, 167 patients (66.8%) reported improvement in overall arthritis status. Changes in pain severity, stiffness severity, and fatigue were the only significant correlates of changes in PGA. In contrast, changes in the Health Assessment Questionnaire, tender joint count or Disease Activity Score-28 (DAS28), and stiffness severity were associated with retrospective judgments of improvement.Conclusions: Prospectively measured changes in PGA in RA were related solely to other patient-reported measures, but patients' retrospective judgments of improvement were related to functional limitations, tender joint count, and DAS28. Patients' subjective judgments of improvement reflect aspects of RA different from the PGA, and may be a simple complementary measure of treatment efficacy. © 2014 American College of Rheumatology.
    Arthritis Care & Research. 10/2014;
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    ABSTRACT: Objective: Systemic lupus erythematosus (SLE) has among the highest hospital readmission rates among chronic conditions. We sought to identify patient-level, hospital-level, and geographic predictors of 30-day hospital readmissions in SLE.Methods: Using hospital discharge databases from 5 geographically dispersed states, we performed a study of all-cause SLE readmissions between 2008 and 2009. We evaluated each hospitalization as a possible index event leading up to a readmission, our primary outcome. We accounted for clustering of hospitalizations within patients and within hospitals and adjusted for hospital case-mix. Using multi-level mixed-effects logistic regression, we examined factors associated with 30-day readmissions and calculated risk-standardized hospital-level and state-level readmission rates.Results: We examined 55,936 hospitalizations among 31,903 patients with SLE. 9,244 (16.5%) hospitalizations resulted in readmission within 30 days. In adjusted analyses, age was inversely related to risk of readmission. Black and Hispanic patients were more likely to be readmitted compared to white patients, as were those with Medicare or Medicaid insurance (versus private insurance). Several lupus clinical characteristics, including lupus nephritis, serositis and thrombocytopenia were associated with readmission. Readmission rates varied significantly between hospitals after accounting for patient-level clustering and hospital case mix. There was also geographic variation, with risk-adjusted readmission rates lower in New York and higher in Florida compared to California.Conclusions: We found that about 1 in 6 hospitalized patients with SLE were readmitted within 30 days, with higher rates in historically underserved populations. Significant geographic and hospital-level variation in risk-adjusted readmission rates suggests potential for quality improvement. © 2014 American College of Rheumatology.
    Arthritis & Rheumatology. 06/2014;
  • Michael M. Ward, Lori C. Guthrie, Maria I. Alba
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    ABSTRACT: Objective: Despite wide use of the Short-Form 36 (SF-36) in clinical trials of rheumatoid arthritis (RA), estimates of minimal clinically important improvement (MCII) for its scales are not well-established. We estimated MCIIs for SF-36 scales in patients with active RA.Methods: In this prospective longitudinal study, we studied 243 patients who had active RA, and who completed the SF-36 before and after treatment escalation. We first assessed responsiveness with standardized response means (SRM). For scales with adequate responsiveness (SRM ≥ 0.50), we used patient judgments of improvement in arthritis status as anchors for estimating MCIIs. We used receiver operating characteristic curve analysis to identify the MCIIs as the change associated with a specificity of 0.80 for improvement.Results: Patients had substantial improvement in RA activity with treatment. However, among SF-36 scales, only the physical functioning and bodily pain scale and the physical component summary had adequate responsiveness. Using 0.80 specificity for improvement as the criterion, the MCIIs were 7.1 for the physical functioning scale, 4.9 for the bodily pain scale, and 7.2 for the physical component summary.Conclusions: Low responsiveness precluded estimation of valid MCIIs for many SF-36 scales in patients with RA, particularly the scales assessing mental health. Although the SF-36 has been included in many clinical trials to broaden the assessment of health status, low responsiveness limits the interpretation of changes in its mental health-related scales. © 2014 American College of Rheumatology.
    Arthritis Care & Research. 06/2014;
  • Michael M Ward, Lori C Guthrie, Maria I Alba
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    ABSTRACT: Thresholds of minimal clinically important improvement (MCII) are needed to plan and interpret clinical trials. We estimated MCIIs for the rheumatoid arthritis (RA) activity measures of patient global assessment, pain score, Health Assessment Questionnaire Disability Index (HAQ), Disease Activity Score-28 (DAS28), Simplified Disease Activity Index (SDAI), and Clinical Disease Activity Index (CDAI). In this prospective longitudinal study, we studied 250 patients who had active RA. Disease activity measures were collected before and either 1 month (for patients treated with prednisone) or 4 months (for patients treated with disease modifying medications or biologics) after treatment escalation. Patient judgments of improvement in arthritis status were related to prospectively assessed changes in the measures. MCIIs were changes that had a specificity of 0.80 for improvement based on receiver operating characteristic curve analysis. We used bootstrapping to provide estimates with predictive validity. At baseline, the mean (±SD) DAS28-ESR (erythrocyte sedimentation rate) was 6.16±1.2 and mean SDAI was 38.6±14.8. Improvement in overall arthritis status was reported by 167 patients (66.8%). Patients were consistent in their ratings of improvement versus no change or worsening, with receiver operating characteristic curve areas ≥0.74. MCIIs with a specificity for improvement of 0.80 were: patient global assessment -18, pain score -20, HAQ -0.375, DAS28-ESR -1.2, DAS28-CRP (C-reactive protein) -1.0, SDAI -13, and CDAI -12. MCIIs for individual core set measures were larger than previous estimates. Reporting the proportion of patients who meet these MCII thresholds can improve the interpretation of clinical trials in RA.
    Annals of the rheumatic diseases 05/2014; · 8.11 Impact Factor
  • Michael M. Ward, Lori C. Guthrie, Maria I. Alba
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    ABSTRACT: Objective: We examined the association of the American College of Rheumatology (ACR) response criteria (ACR20, ACR50, ACR70) and the European League Against Rheumatism (EULAR) response criteria with patient-reported improvement in rheumatoid arthritis (RA) activity.Methods: We studied 250 patients with active RA before and after escalation of anti-rheumatic treatment in a prospective longitudinal study. We asked patients to report if they subjectively judged if they had experienced important improvement with treatment, and compared the proportion that reported improvement with the proportion that met ACR20, ACR50, ACR70, and EULAR responses.Results: Improvement in overall arthritis status was reported by 167 patients (66.8%), while 107 patients (42.8%) had an ACR20 response, 52 (20.8%) had an ACR50 response, 24 (9.6%) had an ACR70 response, and 136 (54.4%) had a EULAR moderate/good response. An ACR20 response had a sensitivity of 0.57 and a specificity of 0.85 for clinically important improvement as judged by patients. Sensitivities of the ACR50, ACR70, and EULAR moderate/good responses were 0.30, 0.14, and 0.68, respectively, while their specificities were 0.97, 0.99, and 0.73, respectively. The ACR hybrid score with the highest sensitivity and specificity for important improvement was 19.99%.Conclusions: Among patients with active RA, ACR20 responses are highly specific measures of improvement as judged by patients, but exclude a substantial proportion of patients who consider themselves improved. Response criteria are associated with, but not equivalent to, patient-perceived improvement. © 2014 American College of Rheumatology.
    Arthritis & Rheumatology. 05/2014;
  • Grant H Louie, Michael M Ward
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    ABSTRACT: One of the major goals of treatment of ankylosing spondylitis is to prevent or slow the development of spinal new bone formation. Recent observational studies are compared with the results from clinical trials for the effects of tumor necrosis factor-alpha inhibitors (TNFi) and NSAIDs on radiographic measures of spinal damage. Data from clinical trials indicate that treatment up to 2 years with TNFi was not associated with a difference in rates of progression of spinal damage, compared with historical controls. These studies were based on open-label extensions, and analyzed as cohort studies. Recent observational studies have suggested that TNFi may reduce radiographic progression. The different conclusions may be related to the longer treatment and observation period of these observational studies, which may have permitted detection of changes in this slowly evolving process. There is emerging evidence from a clinical trial and retrospective studies that continuous NSAID use may slow radiographic progression. Lack of evidence that TNFi slows radiographic progression in ankylosing spondylitis in data from clinical trials may be because of the design of these studies, and possibly not a true null treatment effect.
    Current opinion in rheumatology 01/2014; · 4.60 Impact Factor
  • Michael M. Ward, Lori C. Guthrie, Maria Alba
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    ABSTRACT: Objective Estimates of minimal clinically important improvements (MCIIs) are larger among patients with higher values at baseline, suggesting that these patients require larger changes to appreciate improvements. We examined if baseline dependency of MCIIs was associated with specific patients across three measures, or was owing to floor and ceiling effects. Study Design and Setting We prospectively examined 250 outpatients with active rheumatoid arthritis (RA). We used an anchor-based approach to estimate MCIIs for three measures of RA activity (patient global assessment, swollen joint count, and walking time). We examined if the same patients constituted the baseline subgroups with high MCIIs across measures. Results The MCIIs were greater for those with higher baseline values of all three measures. At the ceiling, there was little opportunity to improve, and judgments were unrelated to measured changes. At midrange, improvements were balanced by worsenings, including some judged as improvements. At the floor, improvements were not similarly balanced. Patients in subgroups with high MCII for patient global assessment were not also predominantly in subgroups with high MCII for the swollen joint count or walking time, and vice versa. Conclusion Variation in MCII by baseline values is because of floor and ceiling effects rather than expectations of particular patients.
    Journal of clinical epidemiology 01/2014; · 5.48 Impact Factor
  • Michael M. Ward
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    ABSTRACT: Recent clinical trials have provided evidence for the efficacy of low-dose intravenous cyclophosphamide and mycophenolate mofetil as induction treatment for patients with proliferative lupus nephritis in comparative trials with standard-dose intravenous cyclophosphamide. Trials of maintenance treatments have had more variable results, but suggest that the efficacy of mycophenolate mofetil may be similar to that of quarterly standard-dose intravenous cyclophosphamide and somewhat more efficacious than azathioprine. Differential responses to mycophenolate mofetil based on ethnicity suggest that it may be more effective in black and Hispanic patients. Rituximab was not efficacious as an adjunct to induction treatment with mycophenolate mofetil.
    Rheumatic Disease Clinics of North America 01/2014; · 2.10 Impact Factor
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    ABSTRACT: Accurate measurement of syndesmophyte development and growth in ankylosing spondylitis (AS) is needed for studies of biomarkers and of treatments to slow spinal fusion. We tested the longitudinal validity and sensitivity to change of quantitative measurement of syndesmophytes using CT. We performed lumbar spine CT scans on 33 patients with AS at baseline, 1 year and 2 years. Volumes and heights of syndesmophytes were computed in four intervertebral disk spaces. We compared the computed changes to a physician's ratings of change based on CT scan inspection. Sensitivity to change of the computed measures was compared with that of the modified Stoke AS Spinal Score (radiography) and a scoring method based on MRI. At years 1 and 2, respectively 24 (73%) and 26 (79%) patients had syndesmophyte volume increases by CT. At years 1 and 2, the mean (SD) computed volume increases per patient were, respectively 87 (186) and 201 (366) mm(3). Computed volume changes were strongly associated with the physician's visual ratings of change (p<0.0002 and p<0.0001 for changes at years 1 and 2, respectively). The sensitivity to change over 1 year was higher for the CT volume measure (1.84) and the CT height measure (1.22) than either the MRI measure (0.50) or radiography (0.29). CT-based syndesmophytes measurements had very good longitudinal validity and better sensitivity to change than radiography or MRI. This method shows promise for longitudinal clinical studies of syndesmophyte development and growth.
    Annals of the rheumatic diseases 12/2013; · 8.11 Impact Factor
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    ABSTRACT: Abstract Purpose . Time perspective, a psychological construct denoting subjective orientation to either present or future concerns, has been inconsistently associated with healthy behaviors in adults. We hypothesized that associations would be stronger in young adults, who are first developing independent attitudes, than in older adults. Design . Cross-sectional survey. Setting . The study was conducted in three cities in the Mid-Atlantic region. Subjects . Subjects were 790 patrons of barber and beauty shops. Measures . Measures used were the Zimbardo Time Perspective Inventory future, present-fatalistic, and present-hedonistic subscales and current smoking, days per week of recreational exercise, and height and weight, by self-report. Analysis . We tested if associations between time perspective and exercise, obesity, and current smoking differed by age group (18-24 years, 25-34 years, and 35 years and older) using analysis of variance and logistic regression. Results . Higher future time perspective scores, indicating greater focus on future events, was associated with more frequent exercise, whereas higher present-fatalistic time perspective scores, indicating more hopelessness, was associated with less frequent exercise in 18- to 24-year-olds, but not in older individuals. Lower future time perspective scores, and higher present-hedonistic time perspective scores, indicating interest in pleasure-seeking, were also associated with obesity only in 18- to 24-year-olds. Current smoking was not related to time perspective in any age group. Conclusion . Time perspective has age-specific associations with exercise and obesity, suggesting stages when time perspective may influence health behavior decision making.
    American journal of health promotion: AJHP 11/2013; · 2.37 Impact Factor
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    ABSTRACT: We investigated the quality of care and factors associated with variations in care among a national cohort of Medicaid enrollees with incident lupus nephritis. Using Medicaid Analytic eXtract (MAX) files from 47 U.S. states and D.C. for 2000-2006, we identified a cohort of individuals with incident lupus nephritis. We assessed performance on three measures of health care quality: receipt of immunosuppressive, renal-protective anti-hypertensive, and anti-malarial medications. We examined performance on these measures over one year, and applied multivariable logistic regression models to understand whether sociodemographic, geographic or health care access factors were associated with higher performance on quality measures. We identified 1711 Medicaid enrollees with incident lupus nephritis. Performance on quality measures was low at 90 days (21.9% for immunosuppressive therapy, 44.0% for renal protection and 36.4% for anti-malarials), but increased by one year (33.7%, 56.4%, and 45.8%, respectively). Younger individuals, Blacks and Hispanics were more likely to receive immunosuppressive therapy and hydroxychloroquine. Younger individuals were less likely to receive renal-protective anti-hypertensive medications. We found significant geographic variation in performance, with patients in the Northeast receiving higher quality of care compared to other regions. Poor access to health care, as assessed by having a greater number of treat-and-release emergency departments visits compared to ambulatory encounters, was associated with lower receipt of recommended treatment. These nationwide data suggest low overall quality of care and potential delays in care for Medicaid enrollees with incident lupus nephritis. Significant regional differences also suggest room for quality improvement. © 2013 American College of Rheumatology.
    Arthritis care & research. 10/2013;
  • Robert A Colbert, Michael M Ward
    The Lancet 09/2013; · 39.21 Impact Factor
  • Michael M Ward
    The Journal of Rheumatology 08/2013; 40(8):1241-3. · 3.26 Impact Factor
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    ABSTRACT: We studied the effect of Tumor Necrosis Factor-Alpha (TNF)-inhibitors on progressive spine damage in Ankylosing Spondylitis (AS) patients. All AS patients (satisfying the modified New York criteria) prospectively followed and with at least two sets of spinal radiographs at a minimum gap of 1.5 years were included (n=334). Patients received clinical standard of care, which included non-steroidal anti-inflammatory drugs and TNF-inhibitors. Radiographic severity was assessed by the modified Stokes Ankylosing Spondylitis Spine Score (mSASSS). Patients with a rate of progression more than 1 mSASSS unit/year were considered progressors. Univariable and multivariable regression analyses were done. Propensity score matching (PSM) and sensitivity analysis were performed. A zero-inflated negative binomial (ZINB) model was used to analyze the effect of TNF-inhibitor on change in mSASSS with varying follow-up periods. Potential confounders like Bath AS Disease Activity Index (BASDAI), ESR, CRP, HLA-B27, gender, age of onset, smoking and baseline damage were included in the model. TNF-inhibitor treatment was associated with a 50% reduction in the odds of progression (OR: 0.52; CI: 0.30-0.88; p=0.02). Patients with a delay in starting therapy of more than 10 years were more likely to progress compared to those who started earlier (OR=2.4; 95% CI: 1.09-5.3; p=0.03). In the ZINB model TNF-inhibitor use significantly reduced progression when the gap between x-rays was more than 3.9 years. The protective effect of TNF-inhibitors was stronger after propensity score matching. TNF-inhibitors appear to reduce radiographic progression in AS, especially with early initiation and longer duration of follow up. © 2013 American College of Rheumatology.
    Arthritis & Rheumatology 07/2013; · 7.48 Impact Factor
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    ABSTRACT: OBJECTIVE: The human major histocompatibility complex class I chain-related gene A (MICA) controls the immune process by balancing activities of natural killer cells, γδ T cells and αβ CD8 T cells, and immunosuppressive CD4 T cells. MICA is located near HLA-B on chromosome 6. Recent genomewide association studies indicate that genes most strongly linked to ankylosing spondylitis (AS) susceptibility come from the region containing HLA-B and MICA. While HLA-B27 is a well-known risk genetic marker for AS, the potential effect of linkage disequilibrium (LD) shields any associations of genes around HLA-B with AS. The aim of this study was to investigate a novel independent genetic association of MICA to AS. METHODS: We examined 1543 AS patients and 1539 controls from two ethnic populations by sequencing MICA and genotyping HLA-B alleles. Initially, 1070 AS patients and 1003 controls of European ancestry were used as a discovery cohort, followed by a confirmation cohort of 473 Han Chinese AS patients and 536 controls. We performed a stratified analysis based on HLA-B27 carrier status. We also conducted logistic regression with a formal interaction term. RESULTS: Sequencing of MICA identified that MICA*007:01 is a significant risk allele for AS in both Caucasian and Han Chinese populations, and that MICA*019 is a major risk allele in Chinese AS patients. Conditional analysis of MICA alleles on HLA-B27 that unshielded LD effect confirmed associations of the MICA alleles with AS. CONCLUSIONS: Parallel with HLA-B27, MICA confers strong susceptibility to AS in US white and Han Chinese populations.
    Annals of the rheumatic diseases 06/2013; · 8.11 Impact Factor
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    ABSTRACT: BACKGROUND: While arthritis is the most common cause of disability, non-Hispanic blacks and Hispanics experience worse arthritis impact despite having the same or lower prevalence of arthritis compared to non-Hispanic whites. People with arthritis who exercise regularly have less pain, more energy, and improved sleep, yet arthritis is one of the most common reasons for limiting physical activity. Mind-body interventions, such as yoga, that teach stress management along with physical activity may be well suited for investigation in both osteoarthritis and rheumatoid arthritis. Yoga users are predominantly white, female, and college educated. There are few studies that examine yoga in minority populations; none address arthritis. This paper presents a study protocol examining the feasibility and acceptability of providing yoga to an urban, minority population with arthritis.Methods/design: In this ongoing pilot study, a convenience sample of 20 minority adults diagnosed with either osteoarthritis or rheumatoid arthritis undergo an 8-week program of yoga classes. It is believed that by attending yoga classes designed for patients with arthritis, with racially concordant instructors; acceptability of yoga as an adjunct to standard arthritis treatment and self-care will be enhanced. Self-care is defined as adopting behaviors that improve physical and mental well-being. This concept is quantified through collecting patient-reported outcome measures related to spiritual growth, health responsibility, interpersonal relations, and stress management. Additional measures collected during this study include: physical function, anxiety/depression, fatigue, sleep disturbance, social roles, and pain; as well as baseline demographic and clinical data. Field notes, quantitative and qualitative data regarding feasibility and acceptability are also collected. Acceptability is determined by response/retention rates, positive qualitative data, and continuing yoga practice after three months. DISCUSSION: There are a number of challenges in recruiting and retaining participants from a community clinic serving minority populations. Adopting behaviors that improve well-being and quality of life include those that integrate mental health (mind) and physical health (body). Few studies have examined offering integrative modalities to this population. This pilot was undertaken to quantify measures of feasibility and acceptability that will be useful when evaluating future plans for expanding the study of yoga in urban, minority populations with arthritis.Trial registration: ClinicalTrials.gov: NCT01617421.
    Health and Quality of Life Outcomes 04/2013; 11(1):55. · 2.27 Impact Factor
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    ABSTRACT: To examine associations between time perspective and smoking, body mass index, and exercise. In this community-based survey, adults reported smoking and exercise habits and weight and height and completed the Zimbardo Time Perspective Inventory. Subjects (N=265) who were more future oriented reported more frequent exercise, but were more likely to smoke. Fatalistic and hedonistic present orientations were not associated with smoking, obesity, or exercise. Time perspective is not consistently associated with common health behaviors in adults.
    American journal of health behavior 03/2013; 37(2):171-80. · 1.31 Impact Factor
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    ABSTRACT: OBJECTIVE: Syndesmophyte growth in ankylosing spondylitis can be difficult to measure using radiographs because of poor visualisation and semiquantitative scoring methods. We developed and tested the reliability and validity of a new computer-based method that fully quantifies syndesmophyte volumes and heights on CT scans. METHODS: In this developmental study, we performed lumbar spine CT scans on 38 patients and used our algorithm to compute syndesmophyte volume and height in four intervertebral disk spaces. To assess reliability, we compared results between two scans performed on the same day in nine patients. To assess validity, we compared computed measures to visual ratings of syndesmophyte volume and height on both CT scans and radiographs by two physician readers. RESULTS: Coefficients of variation for syndesmophyte volume and height, based on repeat scans, were 2.05% and 2.40%, respectively. Based on Bland-Altman analysis, an increase in syndesmophyte volume of more than 4% or in height of more than 0.20 mm represented a change greater than measurement error. Computed volumes and heights were strongly associated with physician ratings of syndesmophyte volume and height on visual examination of both the CT scans (p<0.0001) and plain radiographs (p<0.002). Syndesmophyte volumes correlated with the Schober test (r=-0.48) and lateral thoracolumbar flexion (r=-0.60). CONCLUSIONS: This new CT-based method that fully quantifies syndesmophytes in three-dimensional space had excellent reliability and face and construct validity. Given its high precision, this method shows promise for longitudinal clinical studies of syndesmophyte development and growth.
    Annals of the rheumatic diseases 01/2013; · 8.11 Impact Factor
  • Sovira Tan, Jianhua Yao, Lawrence Yao, Michael M Ward
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    ABSTRACT: Purpose: Evaluation of treatments of many spine disorders requires precise measurement of the heights of vertebral bodies and disk spaces. The authors present a semiautomated computer algorithm measuring those heights from spine computed tomography (CT) scans and evaluate its precision.Methods: Eight patients underwent two spine CT scans in the same day. In each scan, five thoracolumbar vertebral heights and four disk heights were estimated using the algorithm. To assess precision, the authors computed the differences between the height measurements in the two scans, coefficients of variation (CV), and 95% limits of agreement. Intraoperator and interoperator precisions were evaluated. For local vertebral and disk height measurement (anterior, middle, posterior) the algorithm was compared to a manual mid-sagittal plane method.Results: The mean (standard deviation) interscan difference was as low as 0.043 (0.031) mm for disk heights and 0.044 (0.043) mm for vertebral heights. The corresponding 95% limits of agreement were [-0.085, 0.11] and [-0.10, 0.12] mm, respectively. Intraoperator and interoperator precision was high, with a maximal CV of 0.30%. For local vertebral and disk heights, the algorithm improved upon the precision of the manual mid-sagittal plane measurement by as much as a factor of 6 and 4, respectively.Conclusions: The authors evaluated the precision of a novel computer algorithm for measuring vertebral body heights and disk heights using short term repeat CT scans of patients. The 95% limits of agreement indicate that the algorithm can detect small height changes of the order of 0.1 mm.
    Medical Physics 01/2013; 40(1):011905. · 2.91 Impact Factor

Publication Stats

3k Citations
674.36 Total Impact Points


  • 2004–2014
    • National Institute of Arthritis and Musculoskeletal and Skin Diseases
      Maryland, United States
  • 2003–2013
    • National Institutes of Health
      • National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
      Bethesda, MD, United States
  • 2012
    • The Reading Hospital and Medical Center
      West Reading, Pennsylvania, United States
    • Duke University
      Durham, North Carolina, United States
    • Allegheny General Hospital
      Pittsburgh, Pennsylvania, United States
    • University of Texas Health Science Center at Houston
      Houston, Texas, United States
    • University of Toronto
      • Department of Laboratory Medicine and Pathobiology
      Toronto, Ontario, Canada
  • 2011
    • National Technical University of Athens
      Athínai, Attica, Greece
  • 2007
    • Cedars-Sinai Medical Center
      • Cedars Sinai Medical Center
      Los Angeles, CA, United States
    • University of Pittsburgh
      • Division of Rheumatology and Clinical Immunology
      Pittsburgh, PA, United States
  • 2001–2007
    • Stanford Medicine
      Stanford, California, United States
  • 2006
    • U.S. Department of Health and Human Services
      Washington, Washington, D.C., United States
  • 2001–2002
    • VA Palo Alto Health Care System
      Palo Alto, California, United States