V W Y Hung

The Chinese University of Hong Kong, Hong Kong, Hong Kong

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Publications (33)77.04 Total impact

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    ABSTRACT: We investigated the densitometric and microstructural features of the distal radius in psoriatic arthritis (PsA) patients using high-resolution peripheral quantitative computed tomography. PsA patients have unique bone microstructural deficits, manifested as lower cortical bone density and higher cortical porosity, which are associated with a propensity to bone fragility.
    Osteoporosis International 08/2014; · 4.04 Impact Factor
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    ABSTRACT: We conducted a cohort study to investigate if the vessel calcifications (VCs) found in the distal extremities are an index of low bone mass at multiskeletal sites. A total of 332 healthy women aged 41–80 years were recruited for bone mineral content (BMC) and bone mineral density measurement using peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA). Seven percent of the women showed VC at both upper and lower distal extremities based on pQCT images. Women who had VC were then compared with their age-matched non-VC counterparts. Results showed that peripheral VC was mainly formed at distal lower extremities, and the prevalence of VC increased with advancing age, with 0%, 5.6%, 9.3%, and up to 34.5% in the age groups of 41–50 years, 51–60 years, 61–70 years, and 71–80 years, respectively. Compared with the control group, the VC group showed a significantly higher body mass index (25.2 vs. 23.2, p < 0.01), lower BMC at the spine (27.4 g vs. 31.3 g, p < 0.05), and lower BMC (1.8 g vs. 2.0 g, p < 0.05) and bone mineral density (0.57 g/cm2 vs. 0.66 g/cm2, p < 0.05) at the hip as measured by DXA. The diagnosis of VC in the distal extremities by pQCT increased the diagnosis sensitivity of osteoporosis by 50%. The significance of our findings imply that in clinical settings using pQCT for bone assessment and identification of patients with VC in the distal extremities, patients should also be referred for central DXA measurement at the femoral neck for diagnosis of osteoporosis as well as further assessment of vascular disorders.
    Journal of Orthopaedic Translation. 01/2014; 2(1):43–48.
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    ABSTRACT: Adolescent idiopathic scoliosis (AIS) is associated with low bone mineral density (BMD). The underlying etiology and how it may relate to the development of osteopenia remains unknown. Leptin has been postulated as one of the etiologic factors of AIS because of its profound effects on bone metabolism and pubertal growth. Its modulator, soluble leptin receptor (sOB-R), may affect leptin bioavailability and signaling. This study aimed to investigate whether serum leptin and sOB-R levels may be associated with bone quality, and whether these relationships may differ between young adolescent girls with and without AIS. This was a case-control study involving 94 newly diagnosed AIS girls (Cobb angle 12-48°) aged 12 to 14 years old and 87 age and gender-matched normal controls. Subjects with BMI>23.0 Kg/m(2) were excluded. Anthropometric measurements including body weight, height, arm span and sitting height were taken. Serum total leptin and sOB-R were assayed with ELISA. Non-dominant distal radius was scanned with High Resolution pQCT for assessing bone quality in terms of bone morphometry, volumetric BMD (vBMD) and trabecular bone micro-architecture. Compared with normal controls, AIS girls had numerically higher sOB-R (p = 0.006), lower average vBMD (p = 0.048), lower cortical vBMD (p = 0.029), higher cortical bone perimeter (p = 0.014) and higher trabecular area (p = 0.027), but none remained statistically significant after the Hochberg-Benjamini procedure. Correlation analysis on serum leptin level indicated that distinctive correlations with trabecular bone parameters occurred only in AIS. This study showed that bone quality in AIS girls was deranged as compared with controls. In addition, the distinct differences in correlation pattern between leptin and trabecular bone parameters indicated possible abnormalities in bone metabolism and dysfunction of the leptin signaling pathway in AIS.
    PLoS ONE 01/2014; 9(2):e87939. · 3.53 Impact Factor
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    ABSTRACT: Adolescent idiopathic scoliosis (AIS) is prevalent among adolescents and can carry significant morbidities. We evaluated the use of quantitative ultrasound (QUS) for predicting curve progression in patients with AIS. We recruited 294 girls with AIS at a mean age of 13.4 years, and they were prospectively followed beyond skeletal maturity for curve progression. We recorded 3 calcaneal QUS measurements at baseline, namely broadband ultrasound attenuation (BUA), velocity of sound (VOS), and stiffness index (SI). Logistic regression analysis indicated that SI, age, menarchal status, and Cobb angle were significant prognostic factors to be included in the final prediction model. The adjusted odds ratio of curve progression for Z-score of SI≦0 was 2.00 (95% CI: 1.08-3.71). The area under the ROC curve was 0.831 (95% CI: 0.785-0.877). The results of this study indicate that SI was an independent and significant prognostic factor for AIS and could be considered in addition to other prognostic factors when estimating the risk for curve progression and planning treatment for patients with AIS.
    Ultrasound in medicine & biology 12/2012; · 2.46 Impact Factor
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    ABSTRACT: Compared to controls, HR-pQCT at distal radius of SLE patients on chronic glucocorticoid (SLE/GC) revealed reduced bone area, vBMD, deteriorated microarchitecture, and unevenly distributed stresses limited to cortical bone. Despite similar trabecular quality, whole bone strength decreased in patients. These alterations may partly explain high fracture rates in SLE/GC. INTRODUCTION: To assess bone geometric, densitometric, microarchitectural, and biomechanical properties in patients with systemic lupus erythematosus (SLE) on long-term glucocorticoid (GC) (SLE/GC) as compared with healthy controls. METHODS: A total of 180 female SLE patients and 180 healthy controls were in this cross-sectional study to assess areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry. High-resolution peripheral quantitative computed tomography (HR-pQCT) and microfinite element analysis (μFEA) was performed at distal radius. RESULTS: In addition to significantly lower aBMD at femoral neck, total hip and lumbar spine, cortical area, average volumetric BMD (vBMD) and cortical vBMD also significantly reduced by 5.3, 5.7, to 1.9 % in SLE patients, respectively. Deteriorations of cortical microarchitecture were pronounced in patients, with 6.3 % reduction in cortical thickness and 13.6 % higher in cortical porosity. Local stresses were more unevenly distributed through cortical bone in patients. SLE/GC patients had decreased whole bone stiffness, estimated failure load, and apparent modulus. Parameters related to trabecular bone density and microarchitecture were comparable between patients and controls. CONCLUSION: In SLE/GC patients, despite a reduction in bone area, vBMD and deteriorated microarchitecture and unevenly distributed stresses limited to the cortical compartment, whole bone strength decreased. HR-pQCT and μFEA were promising in elucidating the potential underlying pathophysiology of bone loss and propensity to fracture in SLE/GC and provide us additional information about alterations of bone quality which might better predict fracture risk beyond aBMD in SLE/GC.
    Osteoporosis International 10/2012; · 4.04 Impact Factor
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    ABSTRACT: We assessed the relationship of bone density and microarchitecture between hand, peripheral, and axial skeletal sites using high-resolution peripheral quantitative computed tomography (HR-pQCT) and dual-energy X-ray absorptiometry (DXA) in patients with rheumatoid arthritis (RA) and which factors influence these parameters. This was a cross-sectional study of 100 female patients (53.4 ± 9.3 years) with RA. HR-pQCT scans at distal radius and the second metacarpal head were performed to assess cortical and trabecular volumetric bone mineral density (vBMD) and microarchitecture. DXA scans at the hip, lumbar spine, and ultradistal radius were performed to assess areal BMD. There was significant correlation in vBMD and microarchitectural parameters between the second metacarpal head and distal radius (r = 0.201-0.628). Areal BMD at the axial skeleton was moderately associated with vBMD at the peripheral sites (r = 0.354-0.558). Factors related to disease severity/chronicity significantly correlated with vBMD and microarchitecture at the distal radius and the second metacarpal head. Factors related to disease activity were more likely to correlate with vBMD and microarchitecture at the second metacarpal head but not those at the distal radius. HR-pQCT is a promising technique that is capable of providing detailed quantitative assessment of disease-associated periarticular bone loss at both cortical and trabecular bone compartments in patients with RA. Future longitudinal studies will be needed to investigate whether assessment by HR-pQCT can be used as a marker of disease activity and a predictor of disease progression in RA.
    Calcified Tissue International 09/2012; 91(5):343-55. · 2.75 Impact Factor
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    ABSTRACT: To evaluate bone quality in patients with systemic lupus erythematosus (SLE) who were undergoing longterm glucocorticoid (GC) therapy, and to focus on the correlation between bone quality and organ damage. Seventy-eight female patients with SLE and organ damage taking longterm GC, and 72 age-matched SLE patients without damage taking longterm GC were recruited for study. Clinical variables of interest included disease activity, cumulative organ damage (by Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index; SDI), major organ involvement (musculoskeletal damage and neuropsychiatric damage, etc.), and use of medication. Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry. Bone geometry, volumetric BMD (vBMD), microarchitecture, and biomechanical properties were measured by high-resolution peripheral quantitative computed tomography (HR-pQCT). Patients were mean age of 45 years (SD 10) and 54% were postmenopausal. The median SDI score of the cohort was 1 (interquartile range 1-2, range 1-5). Compared with patients without damage, the prevalence of osteopenia at either total hip or lumbar spine was significantly higher, and there were trends of deterioration of bone geometry, vBMD, microarchitecture, and biomechanical properties in patients with organ damage. Potential risk factors for bone quality in patients with damage were screened by univariate analysis. During multiple regression analysis, SDI was the only clinical variable consistently associated with deterioration of vBMD and microarchitecture. Cumulative organ damage consistently correlated with deterioration of vBMD and bone microarchitecture in SLE patients with damage on longterm GC therapy. HR-pQCT provides an insight into the underlying mechanism of bone loss in SLE.
    The Journal of Rheumatology 08/2012; 39(10):1955-63. · 3.26 Impact Factor
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    ABSTRACT: A cross-sectional and prospective longitudinal study on the anthropometric parameters and growth pattern of girls with adolescent idiopathic scoliosis (AIS). To investigate the growth pattern of girls with AIS with different severities, using cross-sectional and prospective longitudinal data set in comparison with age-matched healthy controls. AIS occurs in children during their pubertal growth spurt. Although there is no clear consensus on the difference in body height between girls with AIS and healthy controls, it is generally thought that the development and curve progression in girls with AIS is closely associated with their growth rate. There is no concrete prospective longitudinal study to document clearly the growth pattern and growth rate of subjects with AIS . A total of 611 girls with AIS and 296 healthy age-matched controls were included in the study and among them, 194 girls with AIS and 116 healthy controls were followed up until skeletal maturity. The girls with AIS were grouped into moderate (AIS20) and severe curve (AIS40) groups on the basis of maximum curve magnitude at skeletal maturity. Clinical data and detailed anthropometric parameters were recorded. In the cross-sectional analysis, the groups of subjects were compared within different age groups (from the age of 12-16 yr). In the longitudinal study, linear mixed modeling with respect to age or years since menarche was employed to formulate the growth trajectory of different anthropometric parameters. In the cross-sectional analysis, the girls with AIS were generally taller, with longer arm span and lower body mass index than the healthy controls. The girls with AIS40 were found to be significantly shorter in height (P = 0.006) and arm span (P = 0.025) at the age of 12 years but caught up and overtook the control group at the age of 14 to 16 years. In the longitudinal study, the average growth rate of arm span in girls with AIS40 was significantly higher than that in girls with AIS20 (> 30%) (P = 0.004) and controls (> 70%) (P = 0.0004). The age of menarche of girls with AIS40 was significantly delayed by 5.9 months and 3.8 months when compared with the control group and girls with AIS20, respectively (P < 0.05). The growth patterns of girls with AIS with confirmed curve severities were significantly different from healthy age-matched controls. Girls with severe AIS had delayed menarche with faster skeletal growth rate during the age of 12 to 16 years. Monitoring the rate of change of arm span of girls with AIS could be an important additional clinical parameter in helping predict curve severity in girls with AIS.
    Spine 05/2012; 37(18):E1148-54. · 2.16 Impact Factor
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    ABSTRACT: Recent familial segregation studies supported a multifactorial genetic model for the etiology of adolescent idiopathic scoliosis (AIS). However, the extent of quantitative genetic effects, such as heritability, have not been fully evaluated. This genetic epidemiology study examined the sibling recurrent risk and heritability of AIS in first-degree relatives of 415 Chinese female patients, which is up to now the largest cohort. They were first diagnosed by community screening program and compared to 203 age-matched normal controls. Out of the total 531 sibs of AIS cases, 94 sibs had scoliosis (sibling recurrence risk = 17.7%). The prevalence of AIS among male and female sibs of an index case were 11.5% (95% CI = 7.5-15.5) and 23.0% (95% CI = 18.1-27.9), respectively. Female sibs of an index case had an increased risk of 8.9-fold (95% CI = 3.2-34.4) for developing AIS. These recurrent risks were significantly higher than the risk in the control group (p < 0.0001). Overall, heritability was estimated to be 87.5 ± 11.1%. The results confirmed the prevailing impression of strong genetic influence on the risk of AIS. Here we provided a large-scale study for the genetic aggregation estimates in an Asian population for the first time. The finding also positioned AIS among other common disease or complex traits with a high heritability.
    Journal of Orthopaedic Research 02/2012; 30(9):1464-9. · 2.88 Impact Factor
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    ABSTRACT: Introduction: Growth rate and pattern of girls with Adolescent idiopathic scoliosis (AIS) are proposed to be related to its occurrence and progression. The cross-sectional nature of previous studies did not allow a comprehensive understanding of the relationship. The current study aimed to use both cross-sectional and longitudinal anthropometric data to elucidate the growth pattern of AIS girls of different severities. Methodology: 611 AIS and 296 control girls aged between 12 and 16 were recruited. 194 AIS and 116 controls among the recruited subjects participated in the longitudinal study. The AIS girls were further divided into two groups according to their curve severity. Anthropometric parameters were measured at each visit. The differences in all parameters between AIS of different severities and control subjects were analyzed with one-way ANOVA in the cross-sectional study. While the growth patterns in terms of arm span were evaluated by linear mixed model in the longitudinal study. Results: In the cross-sectional study, severe AIS started with a shorter arm span than moderate AIS and control at age 12 but overtook at age 14-16. For the longitudinal analysis from age 12 to 16, moderate AIS had a longer arm span than control but with similar growth rate. While severe AIS had a higher growth rate than moderate AIS by 71% (p=0.001) and control by 30% (p=0.07) respectively. Discussion: Growth spurt during puberty is a key factor associated with the etiopathogenesis and curve progression in AIS. The current study showed that AIS of different severities and normal controls had different growth rate between age 12 and 16, revealing its possible association with scoliosis development and progression. The findings corroborated the hypothesis of abnormal skeletal growth in AIS which may contribute to its etiopathogenesis. The measurement of arm span growth could be an important clinical parameter in helping to predict the development of severe scoliosis in AIS.
    Studies in health technology and informatics 01/2012; 176:474.
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    ABSTRACT: Corticosteroids are prescribed for the treatment of many medical conditions and their adverse effects on bone, including steroid-associated osteoporosis and osteonecrosis, are well documented. Core decompression is performed to treat osteonecrosis, but the results are variable. As steroids may affect bone turnover, this study was designed to investigate bone healing within a bone tunnel after core decompression in an experimental model of steroid-associated osteonecrosis. A total of five 28-week-old New Zealand rabbits were used to establish a model of steroid-induced osteonecrosis and another five rabbits served as controls. Two weeks after the induction of osteonecrosis, core decompression was performed by creating a bone tunnel 3 mm in diameter in both distal femora of each rabbit in both the experimental osteonecrosis and control groups. An in vivo micro-CT scanner was used to monitor healing within the bone tunnel at four, eight and 12 weeks postoperatively. At week 12, the animals were killed for histological and biomechanical analysis. In the osteonecrosis group all measurements of bone healing and maturation were lower compared with the control group. Impaired osteogenesis and remodelling within the bone tunnel was demonstrated in the steroid-induced osteonecrosis, accompanied by inferior mechanical properties of the bone. We have confirmed impaired bone healing in a model of bone defects in rabbits with pulsed administration of corticosteroids. This finding may be important in the development of strategies for treatment to improve the prognosis of fracture healing or the repair of bone defects in patients receiving steroid treatment.
    Journal of Bone and Joint Surgery - British Volume 04/2011; 93(4):558-65. · 2.69 Impact Factor
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    ABSTRACT: A case-control study comparing bone quality in Adolescent Idiopathic Scoliosis (AIS) with normal controls. To evaluate bone quality with quantitative ultrasound (QUS) in AIS and normal controls so as to detect any derangement in bone quality among AIS subjects. AIS is characterized by complex spinal deformities. Despite its high prevalence and clinical impact in adolescents, etiology of AIS remains unknown but one possible mechanism is related to derangement of bony mechanical stability, as quantified by bone mineral density (BMD) and bone quality. AIS is known for its association with osteopenia, but little is known about the bone quality in AIS. With technological advancement, QUS can provide objective measurement of bone quality. In this study, we sought to compare bone quality in AIS with normal controls using QUS in addition to the conventional BMD measurement. Six hundred thirty-five AIS girls and 269 age-matched normal girls were investigated. Broadband ultrasound attenuation (BUA), velocity of sound (VOS), and stiffness index (SI) were measured over the nondominant calcaneus using QUS. The results were correlated with anthropometric measurement, radiologic assessment, and BMD of both hips. The z-score of BMD at the femoral neck of AIS subjects (-0.47 ± 0.97) was significantly lower than that of normal controls (-0.12 ± 1.01, P < 0.001). Crude comparison showed that BUA, VOS, and SI of AIS group were 3.8% (P < 0.01), 0.5% (P = 0.042), and 6.9% (P < 0.01) lower than controls, respectively. After controlling confounding from maturity, body weight, body height, and BMD with multiple linear regression analysis for both mild (Cobb's angle ≤ 25°) and severe (Cobb's angle > 25°) curves, BUA and SI were found to be statistically significantly lower in AIS as compared with controls (P < 0.05). In addition to higher prevalence of osteopenia, AIS patients were also found to have deranged bone quality. These might contribute to the etiopathogenesis of spinal deformities in AIS.
    Spine 01/2011; 36(15):1211-7. · 2.16 Impact Factor
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    ABSTRACT: The purpose of this research is to assess the effects of oral ibandronate on bone microarchitecture by using high-resolution peripheral quantitative computed tomography (HR-pQCT) in patients with systemic lupus erythematosus (SLE) taking a long-term glucocorticoid. In this double-blind placebo-controlled study, 40 Chinese female SLE patients taking prednisolone were randomly assigned to receive either monthly oral ibandronate (150 mg) or placebo with daily 1-hydroxycholecalciferol (Alfacalcidol; 1 μg) and calcium supplement for 12 months. Assessments of bone microarchitecture by using HR-pQCT and area bone mineral density (aBMD) of the lumbar spine and hip with dual-energy x-ray absorptiometry (DXA) were performed at baseline and 12 months. No differences in baseline characteristics were found between the two groups. After 12 months, no statistical differences were noted in any of the bone densities, microarchitectural parameters, or percentage changes of these parameters, as measured with HR-pQCT or DXA between the two groups. However, within the active group, the percentage improvement was significant in cortical bone density (P = 0.023) which was absent in the placebo group. Improvement was also seen in the aBMD of both the lumbar spine (P < 0.0001) and the hip (P < 0.005). In the placebo group, the percentage increase in trabecular separation was significant (P = 0.04), and the percentage improvement in aBMD in the spine also was significant (P = 0.049). Oral ibandronate treatment improves microarchitecture in SLE patients taking long-term glucocorticoid assessed with HR-pQCT, and this new technology may have a role in assessing bony changes in future longitudinal studies in SLE patients. ClinicalTrials.gov identifier: NCT00668330.
    Arthritis research & therapy 10/2010; 12(5):R198. · 4.27 Impact Factor
  • Bone 10/2010; 47. · 4.46 Impact Factor
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    ABSTRACT: High-resolution peripheral quantitative computed tomography (HR-pQCT) is a new noninvasive bone imaging technology that generates high-resolution 3-D images for quantitatively analysis of the bone microarchitecture in human. To enable quantitative evaluation of bone changes, either bone gain or loss, accurate alignment between the baseline and follow-up scans of the same individual is necessary. The major difficulties in achieving efficient and automatic registration of the HR-pQCT data are the large data size, deformations in the nonskeletal structures, and the complexity of the trabecular bone geometry. In this paper, we propose an automatic surface-based approach for fast and accurate registration of the HR-pQCT data, where the rigid registration is applied on the surfaces of the bony structures extracted from the grayscale HR-pQCT. The bony structure segmentation is performed via an automatic method that can adaptively determine the thresholds for separating the bony structure from the background and nonskeletal tissues. Experimental results performed on ten pairs of baseline and follow-up wrist scans of five adolescents and five elderly patients with osteoporosis showed the advantage of the proposed method in the high degree of automation, while the resultant parameters describing bone mineral density and trabecular architecture after registration were comparable with the outputs of the scanner's software. This automatic and accurate matching procedure may contribute to the clinical application and research of HR-pQCT.
    IEEE transactions on information technology in biomedicine: a publication of the IEEE Engineering in Medicine and Biology Society 09/2010; 14(5):1291-7. · 1.69 Impact Factor
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    ABSTRACT: We assessed the relationship between vertebral fracture and bone microarchitecture in patients with systemic lupus erythematosus (SLE) on chronic corticosteroid therapy using high-resolution peripheral quantitative computed tomography (HR-pQCT). Fifty-nine Chinese women with SLE taking corticosteroid were selected to participate in a cross-sectional study. Vertebral fracture was confirmed semiquantitatively by lateral radiographs of the thoracic and lumbar spine. Density and microarchitecture at the distal radius were measured with HR-pQCT. Areal bone mineral density (aBMD) at hip and lumbar spine was measured by dual-energy X-ray absorptiometry (DEXA). Twelve patients had vertebral fractures. The aBMD of spine or hip did not differ between those with and without vertebral fractures. Measures by HR-pQCT revealed that patients with vertebral fractures had significantly lower level of average bone density (p = 0.007), cortical bone density (p = 0.029), trabecular bone density (p = 0.024), trabecular bone volume to tissue volume (p = 0.023), and trabecular thickness (p = 0.011) than those without vertebral fractures. Independent explanatory variables associated with higher risk of vertebral fractures were older age (p = 0.013) and lower average cortical bone density (p = 0.029). Vertebral fracture in patients with SLE on chronic corticosteroid treatment was associated with alterations of bone density and microarchitectures measured by HR-pQCT and DEXA. However, alterations were more pronounced in measurements by HR-pQCT. Low cortical bone density and old age were significant predictors of vertebral fracture risk.
    The Journal of Rheumatology 07/2010; 37(7):1473-9. · 3.26 Impact Factor
  • Spine 01/2010; 35(1):130; author reply 130-1. · 2.16 Impact Factor
  • IEEE Transactions on Information Technology in Biomedicine. 01/2010; 14:1291-1297.
  • Bone 01/2009; 44. · 4.46 Impact Factor
  • Bone 01/2009; 45. · 4.46 Impact Factor

Publication Stats

245 Citations
77.04 Total Impact Points

Institutions

  • 2005–2014
    • The Chinese University of Hong Kong
      • • Department of Orthopaedics and Traumatology
      • • Department of Imaging and Interventional Radiology
      Hong Kong, Hong Kong
    • The Hong Kong Polytechnic University
      Hong Kong, Hong Kong
  • 2010
    • Prince of Wales Hospital, Hong Kong
      Chiu-lung, Kowloon City, Hong Kong
  • 2008
    • Caritas Hong Kong
      Chiu-lung, Kowloon City, Hong Kong