- Email: [email protected]
Official Positions of the International Society for Clinical Densitometry
001-005.Leib
12/29/03
12:47 PM
Page 1
Journal of Clinical Densitometry, vol. 7, no. 1, 1–5, 2004 © Copyright 2004 by Humana Press Inc. All rights of any nature whatsoever reserved. 1094-6950/04/7:1–5/$25.00
Special Report
Official Positions of the International Society for Clinical Densitometry Edward S. Leib, MD, E. Michael Lewiecki, MD, Neil Binkley, MD, and Ronald C. Hamdy, MD For the International Society for Clinical Densitometry
Abstract The International Society for Clinical Densitometry (ISCD) has convened two Position Development Conferences at which a panel of experts agreed on recommendations for performance and clinical applications of bone density testing. These recommendation were reviewed by the ISCD Board of Directors, and those approved by the board are now official positions of the ISCD. These include (1) indications for bone density testing, (2) reference databases for T-scores, (3) standards for performing central dual-energy X-ray absorptiometry (DXA) for diagnosis, (4) interpretation of peripheral bone density results, (5) diagnosis of osteoporosis in postmenopausal women, (6) diagnosis of osteoporosis in men, (7) diagnosis in premenopausal women, (8) diagnosis in children, (9) indications and interpretation for serial bone mass measurement, (10) technical standards for phantom scanning and calibration, (11) technical standards for cross-calibration of DXA systems, and (12) standards for reporting of bone density results including correct nomenclature and preferred number of decimal digits.
the International Society for Clinical Densitometry (ISCD) has convened two Position Development Conferences (PDCs) at which panels of international experts in the field of bone densitometry have considered these issues. Recommendations of the panel have been approved by the ISCD Board of Directors and are official ISCD positions. The ISCD is a not-for-profit multidisciplinary professional society with a mission to enhance knowledge and quality of bone densitometry among healthcare professionals, to provide continuing education courses for clinicians and technologists, to increase patient awareness and access to bone densitometry, and to support clinical and scientific advances in the field. This document summarizes the official positions of the ISCD. Results of the 2001 PDC have been
Introduction With the increasing use of bone density testing for diagnosing osteoporosis and establishing fracture risk, inconsistencies have arisen in the way in which bone densitometry is performed and the results interpreted. Differences in indications for bone mass testing, acquisition techniques, interpretation of results for different ages, genders, race, and ethnicity, quality assurance, reporting methods, and terminology may have adverse effects on patient care and the exchange of scientific information. For this reason,
Received 11/03/03; Revised 11/07/03; Accepted 11/10/03 *Address correspondence to Edward Leib, International Society for Clinical Densitometry, 342 North Main St., West Hartford, CT 06117-2507. E-mail:[email protected]
1
001-005.Leib
12/29/03
12:47 PM
Page 2
2 previously published (1–6). The background and rationale for positions established from the 2003 PDC, held in Cincinnati, Ohio, in July 2003, are presented elsewhere in this issue of the Journal of Clinical Densitometry (7–12).
Positions of the ISCD Indications for Bone Mineral Density Testing • Women 65 yr of age and and older. • Postmenopausal women under 65 yr of age with risk factors. • Men 70 yr of age and older. • Adults with a fragility fracture. • Adults with a disease or condition associated with low bone mass or bone loss. • Adults taking medications associated with low bone mass or bone loss. • Any individual being considered for pharmacologic therapy. • Any individual being treated, to monitor treatment effect. • Any individual not receiving therapy in whom evidence of bone loss would lead to treatment. Women discontinuing estrogen should be considered for bone density testing according to the indications listed above.
Reference Database for T-Scores • Use a uniform white (nonrace adjusted) female normative database for women of all ethnic groups. This only applies to the US population. • Use a uniform white (nonrace adjusted) male normative database for men of all ethnic groups. This only applies to the US population. Central Dual-Energy X-Ray Absorptiometry for Diagnosis • Skeletal sites to measure: – Measure bone mineral density (BMD) at both posterior-anterior (PA) spine and hip in all patients. – Forearm BMD should be measured under the following circumstances: ♦ Hip and/or spine cannot be measured or interpreted. ♦ Hyperparathyroidism. Journal of Clinical Densitometry
Leib et al. ♦ Very obese patients (over the weight limit
for dual-energy X-ray absorptiometry [DXA] table). • Spine region of interest (ROI): – Use PA L1–L4 for spine BMD measurement. – Use all evaluable vertebrae and only exclude vertebrae that are affected by local structural change or artifact. Use three vertebrae if four cannot be used and two if three cannot be used. – Lateral spine should not be used for diagnosis but may have a role in monitoring. • Hip ROI: – Use total proximal femur, femoral neck, or trochanter (whichever is lowest). – BMD may be measured at either hip. – Do not use Ward’s area for diagnosis. – There are insufficient data to determine whether mean T-scores for bilateral hip BMD can be used for diagnosis. – The mean hip BMD can be used for monitoring, with total hip being preferred. • Forearm ROI: – Use 33% radius (sometimes called one-third radius) of the nondominant forearm for diagnosis. Other forearm regions of interest are not recommended.
Peripheral Bone Densitometry • The World Health Organization (WHO) classification for diagnosis of osteoporosis and osteopenia should not be used with peripheral BMD measurement other than 33% radius. • Peripheral measurements: – Are useful for assessment of fracture risk. – Theoretically can be used to identify patients unlikely to have osteoporosis and identify patients who should be treated. However, this cannot be applied in clinical practice until device-specific cut-points are established. – Should not be used for monitoring.
Diagnosis in Postmenopausal Women • The WHO classification (normal, T-score –1.0 or above; osteoporosis, T-score –2.5 or below; osteopenia, T-score between –1.0 and –2.5) should be used. • The lowest T-score of PA spine, femoral neck, total hip, trochanter, or the 33% radius, if measured, should be selected. Volume 7, 2004
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Diagnosis in Men (20 Yr of Age and Older) • The WHO classification should not be applied in its entirety to men. • In men age 65 and older, T-scores should be used and osteoporosis diagnosed if the T-score is at or below –2.5. • In men ages 50 through 64, T-scores may be used and osteoporosis diagnosed if both the T-score is at or below –2.5 and other risk factors for fracture are identified. • Men at any age with secondary causes of low BMD (e.g., glucocorticoid therapy, hypogonadism, hyperparathyroidism) may be diagnosed clinically with osteoporosis supported by findings of low BMD. • The diagnosis of osteoporosis in men under age 50 should not be made on the basis of densitometric criteria alone.
Diagnosis in Premenopausal Women (20 Yr of Age to Menopause) • The WHO classification should not be applied to healthy premenopausal women. • Z-scores rather than T-scores should be used. • Osteoporosis may be diagnosed if there is low BMD with secondary causes (e.g., glucocorticoid therapy, hypogonadism, hyperparathyroidism) or with risk factors for fracture. • The diagnosis of osteoporosis in premenopausal women should not be made on the basis of densitometric criteria alone.
Diagnosis in Children (Males or Females Less Than 20 Yr of Age) • The WHO classification should not be applied to children. • T-scores should not be used in children; Z-scores should be used instead. • T-scores should not appear in reports or on DXA printouts in children. • The diagnosis of osteoporosis in children should not be made on the basis of densitometric criteria alone. • Terminology such as “low bone density for chronologic age” may be used if the Z-score is below –2.0. • Z-scores must be interpreted in light of the best available pediatric databases of age-matched Journal of Clinical Densitometry
• • •
•
•
controls. The reference database should be cited in the report. Spine and total body are the preferred skeletal sites for measurement. The value of BMD to predict fractures in children is not clearly determined. There is no agreement on standards for adjusting BMD or bone mineral content (BMC) for factors such as bone size, pubertal stage, skeletal maturity, or body composition. If adjustments are made, they should be clearly stated in the report. Serial BMD studies should be done on the same machine using the same scanning mode, software, and analysis when appropriate. Changes may be required with growth of the child. Any deviation from standard adult acquisition protocols, such as use of low-density software, or manual adjustment of ROI, should be stated in the report.
Serial BMD Measurement • Serial BMD testing can be used to determine whether treatment should be started on untreated patients, because significant loss may be an indication for treatment. • Serial BMD testing can monitor response to therapy by finding an increase or stability of bone density. • Serial BMD testing can evaluate individuals for nonresponse by finding loss of bone density, suggesting the need for reevaluation of treatment and evaluation for secondary causes of osteoporosis. • Followup BMD testing should be done when the expected change in BMD equals or exceeds the least significant change (LSC). • Intervals between BMD testing should be determined according to each patient’s clinical status. Typically 1 yr after initiation or change of therapy is appropriate, with longer intervals once therapeutic effect is established. • In conditions associated with rapid bone loss, such as glucocorticoid therapy, testing more frequently is appropriate.
Phantom Scanning and Calibration The Quality Control (QC) program at a DXA center should include adherence to manufacturer guidelines for system maintenance. In addition, if not Volume 7, 2004
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4 recommended in the manufacturer protocol, the following QC procedures are advised: • Perform periodic (at least once per week) phantom scans for any DXA system as an independent assessment of system calibration. • Plot and review data from calibration and phantom scans. • Verify the phantom mean BMD after any service performed on the densitometer. • Establish and enforce corrective action thresholds that trigger a call for service. • Maintain service logs. • Comply with government inspections, radiation surveys, and regulatory requirements. • Each DXA center should determine its precision error and calculate the LSC. The precision error supplied by the manufacturer should not be used. • If a DXA center has more than one technologist, an average precision error, combining data from all technologists, should be used to establish precision error and LSC for the center, provided the precision error for each technologist is within a pre-established range of acceptable performance. • At the present time, in the absence of an industrywide competency threshold, the center’s discretion must be used to define acceptable performance. • An industry-wide competency threshold (expressed as the % CV) should be established to define the minimum skill level. This competency threshold could be used to verify that the skill level of different technologists is similar. • Every technologist should perform an in vivo precision assessment using patients who are representative of the clinic’s patient population. • Each technologist should do one complete precision assessment after basic scanning skills have been learned (e.g., manufacturer training) and after having performed approx 100 patient scans. • A repeat precision assessment should be done if a new DXA system is installed. • A repeat precision assessment should be done if a technologist’s skill level has changed. • To perform a precision analysis: – Measure 15 patients three times, or 30 patients two times, repositioning the patient after each scan. – Calculate the root mean square standard deviation (RMS-SD) for the group. Journal of Clinical Densitometry
Leib et al. – Calculate LSC for the group at 95% confidence interval. • Precision assessment should be standard clinical practice. Precision assessment is not research and may potentially benefit patients. It should not require approval of an institutional review board. Adherence to local radiologic safety regulations is necessary. Performance of a precision assessment requires the consent of participating patients.
Cross-Calibration of DXA Systems Until such time as DXA manufacturers develop practical standardized procedures for phantom and in vivo cross-calibration, it is necessary to reestablish the BMD baseline on the new DXA system and not rely on the baseline acquired with the old DXA or cross-calibration formulas.
Baseline DXA Report: Minimum Requirements • Demographics (i.e., name, medical record identifying number, date of birth, sex). • Requesting provider. • Indications for the test. • Manufacturer and model of instrument used. • Technical quality and limitations of the study, stating why a specific site or ROI is invalid or not included. • BMD in g/cm2 for each skeletal site. • The skeletal sites, ROIs, and, if appropriate, the side, that were scanned. • The T-score and/or Z-score where appropriate. • WHO classification for diagnosis in postmenopausal women and in men over age 65 and men from 50 to 65 yr of age with other risk factors. • Risk factors including information regarding previous nontraumatic fractures. • A statement about fracture risk. Any use of relative fracture risk must specify the population of comparison (e.g., young adult or agematched). The ISCD favors the use of absolute fracture risk prediction when such methodologies are established. • A general statement that a medical evaluation for secondary causes of low BMD may be appropriate. • Recommendations for the necessity and timing of the next BMD study. Volume 7, 2004
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Special Report
Followup DXA Report: Minimum Requirements • Statement regarding which previous or baseline study and ROI is being used for comparison. • Statement about the LSC at your center and the statistical significance of the comparison. • Report significant change, if any, between the current and previous study or studies in g/cm2 and percentage. • Comments on any outside study including manufacturer and model on which previous studies were performed and the appropriateness of the comparison. • Recommendations for the necessity and timing of the next BMD study.
DXA Report: Optional Items • Recommendation for further non-BMD testing, such as X-ray, magnetic resonance imaging, computed tomography, etc. • Recommendations for pharmacological and nonpharmacological interventions. • Addition of the percentage compared to a reference population. • Specific recommendations for evaluation of secondary osteoporosis.
DXA Report: Items That Should Not Be Included • A statement that there is bone loss without knowledge of previous bone density. • Mention of “mild,” “moderate,” or “marked” osteopenia or osteoporosis. • Separate diagnoses for different regions of interest (e.g., osteopenia at the hip and osteoporosis at the spine). • Expressions such as, “She has the bones of an 80yr-old,” if the patient is not 80 yr old. • Results from skeletal sites that are not technically valid. • The change in BMD if it is not a significant change based on the precision error and LSC.
DXA Nomenclature • DXA, not DEXA. • T-score - not T score, t-score, or t score • Z-score - not Z score, z-score, or z score Journal of Clinical Densitometry
5
DXA Decimal Digits Preferred number of decimal digits for DXA reporting are as follows: • • • • • •
BMD: three digits (e.g., 0.927 g/cm2). T-score: one digit (e.g., –2.3). Z-score: one digit (e.g., 1.7). BMC: two digits (e.g., 31.76 g). Area: two digits (e.g., 43.25 cm2). % reference database: Integer (e.g., 82%).
References 1. Lenchik L, Leib ES, Hamdy RC, Binkley NC, Miller PD, and Watts NB. 2002 Executive summary International Society for Clinical Densitometry position development conference Denver, Colorado July 20-22, 2001. J Clin Densitom 5 Suppl:51–53. 2 . Lenchik L, Kiebzak GM, and Blunt BA. 2002 What is the role of serial bone mineral density measurements in patient management? J Clin Densitom 5 Suppl:S29–S38. 3 . Hamdy RC, Petak SM, and Lenchik L. 2002 Which central dual X-ray absorptiometry skeletal sites and regions of interest should be used to determine the diagnosis of osteoporosis? J Clin Densitom 5 Suppl:S11–S18. 4 . Binkley NC, Schmeer P, Wasnich RD, and Lenchik L. 2002 What are the criteria by which a densitometric diagnosis of osteoporosis can be made in males and non-Caucasians? J Clin Densitom 5 Suppl:S19–S27. 5. Miller PD, Njeh CF, Jankowski LG, and Lenchik L. 2002 What are the standards by which bone mass measurement at peripheral skeletal sites should be used in the diagnosis of osteoporosis? J Clin Densitom 5 Suppl:S39–S45. 6. Leib ES, Lenchik L, Bilezikian JP, Maricic MJ, and Watts NB. 2002 Position statements of the International Society for Clinical Densitometry: methodology. J Clin Densitom 5 Suppl:S5–S10. 7. International Society for Clinical Densitometry Position Development Conference. Executive summary: Cincinnati Ohio, July 25-27, 2003. 2004 J Clin Densitom 7:7–12. 8. International Society for Clinical Densitometry Position Development Conference. Introduction, methods, and participants. 2004 J Clin Densitom 7:13–15. 9 . International Society for Clinical Densitometry Position Development Conference. The diagnosis of osteoporosis in men, premenopausal women, and children. 2004 J Clin Densitom 7:17–26. 10. International Society for Clinical Densitometry Position Development Conference. Technical standardization for dualenergy x-ray absorptiometry. 2004 J Clin Densitom 7:27–36. 11. International Society for Clinical Densitometry Position Development Conference. Indications and reporting for dual-energy x-ray absorptiometry. 2004 J Clin Densitom 7:37–44. 12. International Society for Clinical Densitometry Position Development Conference. Nomenclature and decimal places in bone densitometry. 2004 J Clin Densitom 7:45–49.
Volume 7, 2004
12/29/03
12:47 PM
Page 1
Journal of Clinical Densitometry, vol. 7, no. 1, 1–5, 2004 © Copyright 2004 by Humana Press Inc. All rights of any nature whatsoever reserved. 1094-6950/04/7:1–5/$25.00
Special Report
Official Positions of the International Society for Clinical Densitometry Edward S. Leib, MD, E. Michael Lewiecki, MD, Neil Binkley, MD, and Ronald C. Hamdy, MD For the International Society for Clinical Densitometry
Abstract The International Society for Clinical Densitometry (ISCD) has convened two Position Development Conferences at which a panel of experts agreed on recommendations for performance and clinical applications of bone density testing. These recommendation were reviewed by the ISCD Board of Directors, and those approved by the board are now official positions of the ISCD. These include (1) indications for bone density testing, (2) reference databases for T-scores, (3) standards for performing central dual-energy X-ray absorptiometry (DXA) for diagnosis, (4) interpretation of peripheral bone density results, (5) diagnosis of osteoporosis in postmenopausal women, (6) diagnosis of osteoporosis in men, (7) diagnosis in premenopausal women, (8) diagnosis in children, (9) indications and interpretation for serial bone mass measurement, (10) technical standards for phantom scanning and calibration, (11) technical standards for cross-calibration of DXA systems, and (12) standards for reporting of bone density results including correct nomenclature and preferred number of decimal digits.
the International Society for Clinical Densitometry (ISCD) has convened two Position Development Conferences (PDCs) at which panels of international experts in the field of bone densitometry have considered these issues. Recommendations of the panel have been approved by the ISCD Board of Directors and are official ISCD positions. The ISCD is a not-for-profit multidisciplinary professional society with a mission to enhance knowledge and quality of bone densitometry among healthcare professionals, to provide continuing education courses for clinicians and technologists, to increase patient awareness and access to bone densitometry, and to support clinical and scientific advances in the field. This document summarizes the official positions of the ISCD. Results of the 2001 PDC have been
Introduction With the increasing use of bone density testing for diagnosing osteoporosis and establishing fracture risk, inconsistencies have arisen in the way in which bone densitometry is performed and the results interpreted. Differences in indications for bone mass testing, acquisition techniques, interpretation of results for different ages, genders, race, and ethnicity, quality assurance, reporting methods, and terminology may have adverse effects on patient care and the exchange of scientific information. For this reason,
Received 11/03/03; Revised 11/07/03; Accepted 11/10/03 *Address correspondence to Edward Leib, International Society for Clinical Densitometry, 342 North Main St., West Hartford, CT 06117-2507. E-mail:[email protected]
1
001-005.Leib
12/29/03
12:47 PM
Page 2
2 previously published (1–6). The background and rationale for positions established from the 2003 PDC, held in Cincinnati, Ohio, in July 2003, are presented elsewhere in this issue of the Journal of Clinical Densitometry (7–12).
Positions of the ISCD Indications for Bone Mineral Density Testing • Women 65 yr of age and and older. • Postmenopausal women under 65 yr of age with risk factors. • Men 70 yr of age and older. • Adults with a fragility fracture. • Adults with a disease or condition associated with low bone mass or bone loss. • Adults taking medications associated with low bone mass or bone loss. • Any individual being considered for pharmacologic therapy. • Any individual being treated, to monitor treatment effect. • Any individual not receiving therapy in whom evidence of bone loss would lead to treatment. Women discontinuing estrogen should be considered for bone density testing according to the indications listed above.
Reference Database for T-Scores • Use a uniform white (nonrace adjusted) female normative database for women of all ethnic groups. This only applies to the US population. • Use a uniform white (nonrace adjusted) male normative database for men of all ethnic groups. This only applies to the US population. Central Dual-Energy X-Ray Absorptiometry for Diagnosis • Skeletal sites to measure: – Measure bone mineral density (BMD) at both posterior-anterior (PA) spine and hip in all patients. – Forearm BMD should be measured under the following circumstances: ♦ Hip and/or spine cannot be measured or interpreted. ♦ Hyperparathyroidism. Journal of Clinical Densitometry
Leib et al. ♦ Very obese patients (over the weight limit
for dual-energy X-ray absorptiometry [DXA] table). • Spine region of interest (ROI): – Use PA L1–L4 for spine BMD measurement. – Use all evaluable vertebrae and only exclude vertebrae that are affected by local structural change or artifact. Use three vertebrae if four cannot be used and two if three cannot be used. – Lateral spine should not be used for diagnosis but may have a role in monitoring. • Hip ROI: – Use total proximal femur, femoral neck, or trochanter (whichever is lowest). – BMD may be measured at either hip. – Do not use Ward’s area for diagnosis. – There are insufficient data to determine whether mean T-scores for bilateral hip BMD can be used for diagnosis. – The mean hip BMD can be used for monitoring, with total hip being preferred. • Forearm ROI: – Use 33% radius (sometimes called one-third radius) of the nondominant forearm for diagnosis. Other forearm regions of interest are not recommended.
Peripheral Bone Densitometry • The World Health Organization (WHO) classification for diagnosis of osteoporosis and osteopenia should not be used with peripheral BMD measurement other than 33% radius. • Peripheral measurements: – Are useful for assessment of fracture risk. – Theoretically can be used to identify patients unlikely to have osteoporosis and identify patients who should be treated. However, this cannot be applied in clinical practice until device-specific cut-points are established. – Should not be used for monitoring.
Diagnosis in Postmenopausal Women • The WHO classification (normal, T-score –1.0 or above; osteoporosis, T-score –2.5 or below; osteopenia, T-score between –1.0 and –2.5) should be used. • The lowest T-score of PA spine, femoral neck, total hip, trochanter, or the 33% radius, if measured, should be selected. Volume 7, 2004
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3
Diagnosis in Men (20 Yr of Age and Older) • The WHO classification should not be applied in its entirety to men. • In men age 65 and older, T-scores should be used and osteoporosis diagnosed if the T-score is at or below –2.5. • In men ages 50 through 64, T-scores may be used and osteoporosis diagnosed if both the T-score is at or below –2.5 and other risk factors for fracture are identified. • Men at any age with secondary causes of low BMD (e.g., glucocorticoid therapy, hypogonadism, hyperparathyroidism) may be diagnosed clinically with osteoporosis supported by findings of low BMD. • The diagnosis of osteoporosis in men under age 50 should not be made on the basis of densitometric criteria alone.
Diagnosis in Premenopausal Women (20 Yr of Age to Menopause) • The WHO classification should not be applied to healthy premenopausal women. • Z-scores rather than T-scores should be used. • Osteoporosis may be diagnosed if there is low BMD with secondary causes (e.g., glucocorticoid therapy, hypogonadism, hyperparathyroidism) or with risk factors for fracture. • The diagnosis of osteoporosis in premenopausal women should not be made on the basis of densitometric criteria alone.
Diagnosis in Children (Males or Females Less Than 20 Yr of Age) • The WHO classification should not be applied to children. • T-scores should not be used in children; Z-scores should be used instead. • T-scores should not appear in reports or on DXA printouts in children. • The diagnosis of osteoporosis in children should not be made on the basis of densitometric criteria alone. • Terminology such as “low bone density for chronologic age” may be used if the Z-score is below –2.0. • Z-scores must be interpreted in light of the best available pediatric databases of age-matched Journal of Clinical Densitometry
• • •
•
•
controls. The reference database should be cited in the report. Spine and total body are the preferred skeletal sites for measurement. The value of BMD to predict fractures in children is not clearly determined. There is no agreement on standards for adjusting BMD or bone mineral content (BMC) for factors such as bone size, pubertal stage, skeletal maturity, or body composition. If adjustments are made, they should be clearly stated in the report. Serial BMD studies should be done on the same machine using the same scanning mode, software, and analysis when appropriate. Changes may be required with growth of the child. Any deviation from standard adult acquisition protocols, such as use of low-density software, or manual adjustment of ROI, should be stated in the report.
Serial BMD Measurement • Serial BMD testing can be used to determine whether treatment should be started on untreated patients, because significant loss may be an indication for treatment. • Serial BMD testing can monitor response to therapy by finding an increase or stability of bone density. • Serial BMD testing can evaluate individuals for nonresponse by finding loss of bone density, suggesting the need for reevaluation of treatment and evaluation for secondary causes of osteoporosis. • Followup BMD testing should be done when the expected change in BMD equals or exceeds the least significant change (LSC). • Intervals between BMD testing should be determined according to each patient’s clinical status. Typically 1 yr after initiation or change of therapy is appropriate, with longer intervals once therapeutic effect is established. • In conditions associated with rapid bone loss, such as glucocorticoid therapy, testing more frequently is appropriate.
Phantom Scanning and Calibration The Quality Control (QC) program at a DXA center should include adherence to manufacturer guidelines for system maintenance. In addition, if not Volume 7, 2004
001-005.Leib
12/29/03
12:47 PM
Page 4
4 recommended in the manufacturer protocol, the following QC procedures are advised: • Perform periodic (at least once per week) phantom scans for any DXA system as an independent assessment of system calibration. • Plot and review data from calibration and phantom scans. • Verify the phantom mean BMD after any service performed on the densitometer. • Establish and enforce corrective action thresholds that trigger a call for service. • Maintain service logs. • Comply with government inspections, radiation surveys, and regulatory requirements. • Each DXA center should determine its precision error and calculate the LSC. The precision error supplied by the manufacturer should not be used. • If a DXA center has more than one technologist, an average precision error, combining data from all technologists, should be used to establish precision error and LSC for the center, provided the precision error for each technologist is within a pre-established range of acceptable performance. • At the present time, in the absence of an industrywide competency threshold, the center’s discretion must be used to define acceptable performance. • An industry-wide competency threshold (expressed as the % CV) should be established to define the minimum skill level. This competency threshold could be used to verify that the skill level of different technologists is similar. • Every technologist should perform an in vivo precision assessment using patients who are representative of the clinic’s patient population. • Each technologist should do one complete precision assessment after basic scanning skills have been learned (e.g., manufacturer training) and after having performed approx 100 patient scans. • A repeat precision assessment should be done if a new DXA system is installed. • A repeat precision assessment should be done if a technologist’s skill level has changed. • To perform a precision analysis: – Measure 15 patients three times, or 30 patients two times, repositioning the patient after each scan. – Calculate the root mean square standard deviation (RMS-SD) for the group. Journal of Clinical Densitometry
Leib et al. – Calculate LSC for the group at 95% confidence interval. • Precision assessment should be standard clinical practice. Precision assessment is not research and may potentially benefit patients. It should not require approval of an institutional review board. Adherence to local radiologic safety regulations is necessary. Performance of a precision assessment requires the consent of participating patients.
Cross-Calibration of DXA Systems Until such time as DXA manufacturers develop practical standardized procedures for phantom and in vivo cross-calibration, it is necessary to reestablish the BMD baseline on the new DXA system and not rely on the baseline acquired with the old DXA or cross-calibration formulas.
Baseline DXA Report: Minimum Requirements • Demographics (i.e., name, medical record identifying number, date of birth, sex). • Requesting provider. • Indications for the test. • Manufacturer and model of instrument used. • Technical quality and limitations of the study, stating why a specific site or ROI is invalid or not included. • BMD in g/cm2 for each skeletal site. • The skeletal sites, ROIs, and, if appropriate, the side, that were scanned. • The T-score and/or Z-score where appropriate. • WHO classification for diagnosis in postmenopausal women and in men over age 65 and men from 50 to 65 yr of age with other risk factors. • Risk factors including information regarding previous nontraumatic fractures. • A statement about fracture risk. Any use of relative fracture risk must specify the population of comparison (e.g., young adult or agematched). The ISCD favors the use of absolute fracture risk prediction when such methodologies are established. • A general statement that a medical evaluation for secondary causes of low BMD may be appropriate. • Recommendations for the necessity and timing of the next BMD study. Volume 7, 2004
001-005.Leib
12/29/03
12:47 PM
Page 5
Special Report
Followup DXA Report: Minimum Requirements • Statement regarding which previous or baseline study and ROI is being used for comparison. • Statement about the LSC at your center and the statistical significance of the comparison. • Report significant change, if any, between the current and previous study or studies in g/cm2 and percentage. • Comments on any outside study including manufacturer and model on which previous studies were performed and the appropriateness of the comparison. • Recommendations for the necessity and timing of the next BMD study.
DXA Report: Optional Items • Recommendation for further non-BMD testing, such as X-ray, magnetic resonance imaging, computed tomography, etc. • Recommendations for pharmacological and nonpharmacological interventions. • Addition of the percentage compared to a reference population. • Specific recommendations for evaluation of secondary osteoporosis.
DXA Report: Items That Should Not Be Included • A statement that there is bone loss without knowledge of previous bone density. • Mention of “mild,” “moderate,” or “marked” osteopenia or osteoporosis. • Separate diagnoses for different regions of interest (e.g., osteopenia at the hip and osteoporosis at the spine). • Expressions such as, “She has the bones of an 80yr-old,” if the patient is not 80 yr old. • Results from skeletal sites that are not technically valid. • The change in BMD if it is not a significant change based on the precision error and LSC.
DXA Nomenclature • DXA, not DEXA. • T-score - not T score, t-score, or t score • Z-score - not Z score, z-score, or z score Journal of Clinical Densitometry
5
DXA Decimal Digits Preferred number of decimal digits for DXA reporting are as follows: • • • • • •
BMD: three digits (e.g., 0.927 g/cm2). T-score: one digit (e.g., –2.3). Z-score: one digit (e.g., 1.7). BMC: two digits (e.g., 31.76 g). Area: two digits (e.g., 43.25 cm2). % reference database: Integer (e.g., 82%).
References 1. Lenchik L, Leib ES, Hamdy RC, Binkley NC, Miller PD, and Watts NB. 2002 Executive summary International Society for Clinical Densitometry position development conference Denver, Colorado July 20-22, 2001. J Clin Densitom 5 Suppl:51–53. 2 . Lenchik L, Kiebzak GM, and Blunt BA. 2002 What is the role of serial bone mineral density measurements in patient management? J Clin Densitom 5 Suppl:S29–S38. 3 . Hamdy RC, Petak SM, and Lenchik L. 2002 Which central dual X-ray absorptiometry skeletal sites and regions of interest should be used to determine the diagnosis of osteoporosis? J Clin Densitom 5 Suppl:S11–S18. 4 . Binkley NC, Schmeer P, Wasnich RD, and Lenchik L. 2002 What are the criteria by which a densitometric diagnosis of osteoporosis can be made in males and non-Caucasians? J Clin Densitom 5 Suppl:S19–S27. 5. Miller PD, Njeh CF, Jankowski LG, and Lenchik L. 2002 What are the standards by which bone mass measurement at peripheral skeletal sites should be used in the diagnosis of osteoporosis? J Clin Densitom 5 Suppl:S39–S45. 6. Leib ES, Lenchik L, Bilezikian JP, Maricic MJ, and Watts NB. 2002 Position statements of the International Society for Clinical Densitometry: methodology. J Clin Densitom 5 Suppl:S5–S10. 7. International Society for Clinical Densitometry Position Development Conference. Executive summary: Cincinnati Ohio, July 25-27, 2003. 2004 J Clin Densitom 7:7–12. 8. International Society for Clinical Densitometry Position Development Conference. Introduction, methods, and participants. 2004 J Clin Densitom 7:13–15. 9 . International Society for Clinical Densitometry Position Development Conference. The diagnosis of osteoporosis in men, premenopausal women, and children. 2004 J Clin Densitom 7:17–26. 10. International Society for Clinical Densitometry Position Development Conference. Technical standardization for dualenergy x-ray absorptiometry. 2004 J Clin Densitom 7:27–36. 11. International Society for Clinical Densitometry Position Development Conference. Indications and reporting for dual-energy x-ray absorptiometry. 2004 J Clin Densitom 7:37–44. 12. International Society for Clinical Densitometry Position Development Conference. Nomenclature and decimal places in bone densitometry. 2004 J Clin Densitom 7:45–49.
Volume 7, 2004