Official positions of the International Society for Clinical Densitometry (ISCD) on DXA evaluation in children and adolescents

Abstract

Dual-energy X-ray absorptiometry (DXA) is the most widely used technical instrument for evaluating bone mineral content (BMC) and density (BMD) in patients of all ages. However, its use in pediatric patients, during growth and development, poses a much more complex problem in terms of both the technical aspects and the interpretation of the results. For the adults population, there is a well-defined term of reference: the peak value of BMD attained by young healthy subjects at the end of skeletal growth. During childhood and adolescence, the comparison can be made only with healthy subjects of the same age, sex and ethnicity, but the situation is compounded by the wide individual variation in the process of skeletal growth (pubertal development, hormone action, body size and bone size). The International Society for Clinical Densitometry (ISCD) organized a Pediatric Position Development Conference to discuss the specific problems of bone densitometry in growing subjects (9–19 years of age) and to provide essential recommendations for its clinical use.

Appendices

Appendix 1: The new ISCD official positions on the skeletal health assessment in children and adolescents (males and females ages 5–19 years)

The new ISCD Official Positions resulting from the 2007 Pediatric PDC are reported below.

Fracture prediction and definition of osteoporosis

• 1. Fracture prediction should primarily identify children at risk of clinically significant fractures, such as the fracture of long bones in the lower extremities, vertebral compression fractures, or two or more long–bone fractures of the upper extremities.

Grade: Fair–C–W–Necessary

• 2. The diagnosis of osteoporosis in children and adolescents should NOT be made on the basis of densitometric criteria alone.

  • 2a. The diagnosis of osteoporosis requires the presence of both a clinically significant fracture history and low bone mineral content or bone mineral density.

  • 2b. A clinically significant fracture history is one or more of the following:

    • long bone fracture of the lower extremities

    • vertebral compression fracture

    • two or more long–bone fractures of the upper extremities

  • 2c. Low bone mineral content or bone mineral density is defined as a BMC or areal BMD Z-score that is less than or equal to −2.0, adjusted for age, gender and body size, as appropriate.

Grade: Fair–C–W–Necessary

DXA assessment in children and adolescents with diseases that may affect the skeleton

• 1. DXA measurement is part of a comprehensive skeletal health assessment in patients with increased risk of fracture.

Grade: Fair–C–W–Necessary

• 2. Therapeutic interventions should not be instituted on the basis of a single DXA measurement.

Grade: Fair–C–W–Necessary

• 3. When technically feasible, all patients should have spine and TBLH BMC and areal BMD measured

• 3a. Prior to initiation of bone-active treatment.

• 3b. To monitor bone-active treatment in conjunction with other clinical data.

Grade: Poor–C–W–Necessary

• 4. In patients with primary bone diseases or potential secondary bone diseases [e.g. due to chronic inflammatory diseases, endocrine disturbances, history of childhood cancer, or prior transplantation (non–renal)], spine and TBLH BMC and areal BMD should be measured at clinical presentation.

Grade: Poor–C–W–Necessary

• 5. In patients with thalassemia major, spine and TBLH BMC and areal BMD should be measured at fracture presentation or at age 10 years, whichever is earlier.

Grade: Fair–C–W–Necessary

• 6. In children with chronic immobilization (e.g. cerebral palsy), spine and TBLH BMC and areal BMD should be measured at fracture presentation.

DXA should not be performed if contractures prevent the safe and appropriate positioning of the child.

Grade: Poor–C–W–Necessary

• 7. The minimum time interval for repeating a bone density measurement to monitor treatment with a bone-active agent or disease processes is 6 months.

Grade: Poor–C–W–Necessary

DXA interpretation and reporting in children and adolescents

• 1. DXA is the preferred method for assessing BMC and areal BMD.

Grade: Good–B–W–Necessary

• 2. The PA spine and TBLH are the most accurate and reproducible skeletal sites for performing BMC and areal BMD measurements.

Grade: Good–B–W–Necessary

• 3. Soft tissue measures in conjunction with whole body scans may be helpful in evaluating patients with chronic conditions associated with malnutrition (such as anorexia nervosa, inflammatory bowel disease, cystic fibrosis), or with both muscle and skeletal deficits (such as idiopathic juvenile osteoporosis).

Grade: Fair–B–W–Necessary

• 4. The hip (including total hip and proximal femur) is not a reliable site for measurement in growing children due to significant variability in skeletal development and lack of reproducible regions of interest.

Grade: Fair–B–W–Necessary

• 5. In children with linear growth or maturational delay, spine and TBLH BMC and areal BMD results should be adjusted for absolute height or height age, or compared to pediatric reference data that provide age-, gender-, and height-specific Z-scores.

Grade: Good–A–W–Necessary

• 6. An appropriate reference data set must include a sample of the general healthy population sufficiently large to characterize the normal variability in bone measures that takes into consideration gender, age, and race/ethnicity.

Grade: Good–A–W–Necessary

• 7. When upgrading densitometer instrumentation or software, it is essential to use reference data valid for the hardware and software technological updates.

Grade: Good–C–W–Necessary

• 8. Baseline DXA reports should contain the following information:

  • DXA manufacturer, model and software version

  • referring physician

  • patient age, gender, race/ethnicity, weight, and height

  • relevant medical history including previous fractures

  • indication for study

  • bone age results, if available

  • technical quality

  • BMC and areal BMD

  • BMC and areal BMD Z-score

  • source of reference data for Z-score calculations

  • adjustments made for growth and maturation

  • interpretation

  • recommendations for the necessity and timing of the next DXA study are optional

Grade: Good–C–W–Necessary

• 9. Serial DXA testing

• 9a. Should be done only when the expected change in areal BMD equals or exceeds the least significant change.

Grade: Fair–C–W–Necessary

• 9b. Serial DXA reports should include the same information as for baseline testing, but additionally include:

  • indications for follow-up scan

  • comparability of studies

  • interval changes in height, weight

  • BMC and areal BMD Z-scores adjusted or unadjusted for height or other adjustments

  • percentage change in BMC and areal BMD and interval change in Z-scores

  • recommendations for the necessity and timing of the next BMD study are optional.

Grade: Fair–C–W–Necessary

• 10. Accurate interpretation of serial DXA results requires knowledge of the least significant change (LSC) for all sites measured and for all technologists at the DXA testing facility.

Grade: Good–A–W–Necessary

• 11. Terminology

T–scores should not appear in pediatric DXA reports.

Grade: Good–C–W–Necessary

The term ‘‘osteopenia’’ should not appear in pediatric DXA reports.

Grade: Good–A–W–Necessary

The term ‘‘osteoporosis’’ should not appear in pediatric DXA reports without knowledge of clinically significant fracture history.

Grade: Good–A–W–Necessary

‘‘Low bone mineral content or bone mineral density for chronologic age’’ is the preferred term when BMC or BMD Z-scores are less than or equal to −2.0.

Grade: Fair–C–W–Necessary

Appendix 2

2007 PDC participants and support staff

Note: Disclosure for the Pediatric PDC Steering Committee and Task Force chairs is available at https://doi.org/www.ISCD.org.

2007 Pediatric PDC steering committee

Sanford Baim, MD, Medical College of Wisconsin, Milwaukee, WI, USA (Co-chair)

Mary B. Leonard, MD, MSCE, Children’s Hospital of Philadelphia, Philadelphia, PA, USA (Co–chair)

Maria Luisa Bianchi, MD, Istituto Auxologico Italiano IRCCS, Milan, Italy

Didier B. Hans, PhD, Geneva University Hospital, Geneva, Switzerland

Heidi Kalkwarf, PhD, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA

Frank Rauch, MD, Shriners Hospital for Children, Montreal, Quebec, Canada

2007 Pediatric PDC moderators

Craig B. Langman, MD, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA

Sanford Baim, MD, Medical College of Wisconsin, Milwaukee, WI, USA

2007 Pediatric PDC expert panelists

Shona L. Bass, PhD, Deakin University, Burwood, VIC, Australia

Thomas O. Carpenter, MD, Yale University School of Medicine, New Haven, CT, USA

Emma Clark, MD, Bristol Royal Infirmary, Bristol, UK

Barbara A. Cromer, MD, Metro Health Medical Center, Cleveland, OH, USA

Tim Cundy, MD, University of Auckland, Auckland, New Zealand

Francis H. Glorieux, MD, PhD, Shriners Hospital for Children, Montreal, QC, Canada

Ghada El–Hajj Fuleihan, MD, MPH, American University of Beirut, Beirut, Lebanon

Sue C. Kaste, DO, St. Jude Children’s Research Hospital, Memphis, TN, USA

Gordon L. Klein, MD, MPH, University of Texas Medical Branch Child Health Center, Galveston, TX, USA

Roman S. Lorenc, MD, PhD, Specjalistyczny Osrodek Medycyny Wieku, Warsaw, Poland

M. Zulf Mughal, MBChB, St. Mary’s Hospital, Manchester, UK

Aenor J. Sawyer, MD, San Ramon Regional Medical Center, San Ramon, CA, USA

Francisco A. Sylvester, MD, Connecticut Children’s Medical Center, Hartford, CT USA

Hiroyuki Tanaka, MD, PhD, Okayama University Graduate School of Medicine & Dentistry, Okayama, Japan

Definitions of Osteoporosis in Children and Adolescents Task Force

Chairs:

Frank Rauch, MD, Shriners Hospital for Children, Montreal, Quebec, Canada

Horacio Plotkin, MD, Children’s Hospital and University of Nebraska Medical Center, Omaha, NE, USA

Task Force members:

Linda A. DiMeglio, MD, MPH, Indiana University School of Medicine, Indianapolis, IN, USA

Raoul Engelbert, PhD, Utrecht University, The Netherlands

Richard C. Henderson, MD, PhD, University of North Carolina, Chapel Hill, NC, USA

Craig F. J. Munns, MBBS, PhD, The Children’s Hospital at Westmead, Westmead, Australia

Deborah Wenkert. MD, Shriners Hospital for Children, St. Louis, MO, USA

Philip Zeitler, MD, PhD, The Children’s Hospital of Denver, Denver, CO, USA

Task Force consultants/advisors:

Frank Rauch, MD, Shriners Hospital for Children, Montreal, Quebec, Canada

DXA Assessment in Children and Adolescents with Diseases that may Affect the Skeleton Task Force

Chair:

Nicholas J. Bishop, MRCP, MD, University of Sheffield, Sheffield, UK

Task Force members:

Maria Luisa Bianchi, MD, Istituto Auxologico Italiano IRCCS, Milan, Italy

Pierre Braillon, MD, Department of Pediatric Imaging, Hospital Debrousse, Lyon, France

Jon Burnham, MD, MSCE, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA

Rolando Cimaz, MD, Azienda Ospedaliera Universitaria Meyer, Florence, Italy

Justin Davies, MD, Southampton University Hospital Trust, Southampton, UK

Mary Fewtrell, MD, MB, ChB, Institute of Child Health, London, UK

Wolfgang Hogler, DSc, Princess of Wales Children’s Hospital Birmingham, Birmingham, UK

Kathy Kennedy, MB, ChB, Institute of Child Health, London, UK

Outi Makitie, MD, Helsinki University Hospital, Helsinki, Finland

M. Zulf Mughal, MBChB, St. Mary’s Hospital, Manchester, UK

Nick Shaw, MD, Birmingham Children’s Hospital, Birmingham, UK

Maria Vogiatzi, MD, New York Presbyterian Hospital, New York, New York, USA

Kate A. Ward, PhD, University of Manchester, Manchester, UK

Task Force Consultants/Advisors:

Maria Luisa Bianchi, MD, Istituto Auxologico Italiano IRCCS, Milan, Italy

DXA Interpretation and Reporting of Bone Densitometry in Children and Adolescents Task Force

Chair:

Catherine M. Gordon, MD, MSc, Children’s Hospital Boston, Boston, MA, USA

Task Force members:

Laura K. Bachrach, MD, Stanford University School of Medicine, Stanford, CA, USA

Thomas O. Carpenter, MD, Yale University School of Medicine, New Haven, CT, USA

Nicola J. Crabtree, BSc, MSc, Queen Elizabeth Hospital Bone Density, Birmingham, UK

Ghada El–Hajj Fuleihan, MD, MPH, American University of Beirut, Beirut, Lebanon

Stepan Kutilek, MD, PhD, Czech, Pardubice, Czech Republic

Roman S. Lorenc, MD, The Children’s Memorial Health Institute, Warsaw, Poland

Laura Tosi, MD, Children’s National Medical Center, Washington, D.C., USA

Kate A.Ward, PhD, University of Manchester, Manchester, UK

Leanne M. Ward, MD, Children’s Hospital of Eastern Ontario, Ottawa, ON, Canada

Task Force consultants/advisors:

Heidi J. Kalkwarf, PhD, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA

ISCD staff

Martin Rotblatt, CAE, Associate Director, ISCD, West Hartford, CT, USA

Appendix 3

Nomenclature

DXA not DEXA

Z-score not Z score, z–score, or z score

DXA decimal digits

Preferred number of decimal digits for DXA reporting:

BMD (e.g. 0.927 g/cm²) 3 digits

Z-score (e.g. 1.7) 1 digit

BMC (e.g. 31.76 g) 2 digits

Area (e.g. 43.25 cm²) 2 digits

Percentage reference database (e.g. 82%) integer

Glossary

BMC:

bone mineral content

BMD:

bone mineral density

DXA:

dual–energy X–ray absorptiometry

ISCD:

International Society for Clinical Densitometry

LSC:

least significant change

NHANES III:

National Health and Nutrition Examination Survey III

PA:

posterior anterior

pDXA:

peripheral dual–energy x–ray absorptiometry

pQCT:

peripheral quantitative computed tomography

QC:

quality control

QCT:

quantitative computed tomography

QUS:

quantitative ultrasound

ROI:

region of interest

SSI:

strain strength index

TBLH:

total body less head

VFA:

vertebral fracture assessment

vBMD:

volumetric BMD

WHO:

World Health Organization