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Protocol - Spine and Femur Bone Density by Dual-Energy X-ray Absorptiometry

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Description:

The Framingham Osteoporosis Study Generation 3 Musculoskeletal Exam includes instructions for preparing the sample person for the scan, performing quality assurance procedures, and performing the scan of the hip and spine.

Protocol:

The following is a summary of the Framingham Osteoporosis Study Generation 3 Musculoskeletal Exam (May 2008–2010) manual. These excerpts refer to a specific make and model dual-energy X-ray absorptiometry (DXA) scanner (GE Lunar densitometer©). Several brands of DXA scanners are available and manufacturer-specific software, calibration, and quality control practices should be followed.

A downloadable procedure manual for the Framingham Osteoporosis Study Generation 3 Musculoskeletal Exam (May 2008–2010) is available.

Framingham Osteoporosis Study Generation 3 Musculoskeletal Exam

A. Pre-Clinic Procedures

Dual energy x-ray absorptiometry poses a radiation hazard. Thus, the Framingham Osteoporosis Study Generation 3 Musculoskeletal Exam includes a pre-clinic pregnancy screening questionnaire which is administered to all women younger than 55 years old ten days prior to the visit. Women who are pregnant or trying to get pregnant are excluded from the exam. Women who do not use birth control are asked to abstain from sex 7 days prior to their exam.

B. Daily Quality Assurance and Phantom Procedures

A quality assurance test is performed each day using a black calibration block which consists of tissue-equivalent material and three bone-simulating chambers of known mineral content. Additionally, an encapsulated spine phantom scan is collected every day to standardize on known "vertebral heights."

C. Participants Enter Main Clinic

The lab technician collects urine for a pregnancy test on all women younger than 55 who have not had a tubal ligation or hysterectomy. The technician uses the results of the pregnancy test to complete the Pregnancy Determination form (see Appendix A of the Framingham Osteoporosis Study Generation 3 Musculoskeletal Exam for form). The lab technician also measures/records the participant's weight and height if they are not already noted.

D. Participants Enter Bone Room

Consent participant/review pregnancy issues

For men and women who are either aged 55 years or older or have had a tubal ligation or hysterectomy, the bone technician will explain and gather consent for the bone scan. For all other women, the bone technician will review the results of the pregnancy test. If the test is positive, the participant is excluded from the test and is asked to reschedule her scan. If the test is negative, the participant is asked whether she had intercourse in the past week. If the participant indicates the possibility of being pregnant, she is excluded from the test and is asked to reschedule her scan. Once the technician establishes that there is no risk of pregnancy, the technician will explain and gather consent for the bone scan.

Participant preparation

The technician asks the participant to remove any metallic items such as rings, piercings, watches, or hair clips. The technician asks the participant whether he or she has implanted metallic medical devices such as spine implants, hip replacements, pins, and screws. The technician notes the location of any metal items that are not removed before the scan.

E. Hip and AP DXA Scan Procedures

DXA scan acquisition

The technician asks the participant whether he or she has had hip implant/replacement to determine which hip to scan. If both hips have been replaced, the hip scan is not performed. The spine scan is completed regardless of any implants.

Prepare the participant for scan

The participant lies in middle of scanning table. The technician measures the participant's waist thickness at the belly button and hip thickness at the inferior iliac spine. The technician records the participant's name, ID, birth date, height, weight, gender, and ethnicity and notes any conditions that may affect DXA scan results.

Femur Scan

The technician makes sure that the participant is correctly positioned in the middle of the table and that the participant's pelvis is flat and that the spine is straight. The technician then correctly positions the leg and stabilizes it with a foot brace and tissue equivalent bags.

The technician monitors the scan image to make sure that the participant is properly positioned. If the scan is too high or too low, the scan is aborted and started again with a new start position. A correct femur image will show the greater trochanter, the femoral neck, and the ischium.

Spine Scan

The technician removes the foot brace and tissue equivalent bags and positions the participant for the spine scan. The technician uses a support block to elevate the participant's legs.

The technician monitors the scan image to make sure that the participant is properly positioned. If the scan is too high or too low, the scan is aborted and started again with a new start position. The technician notes any artifacts seen in the scan. A correct spine image will show the spine in the center, include all of L4, the top of L5 and approximately half of T12.

DXA scan analysis

Femur scan

The technician adjusts the image so that the bone edges can be clearly seen and makes sure that the bone and tissue are correctly identified by the analysis software. The technician ensures the region of interest is correctly positioned as follows:

  1. The Neck Region of Interest (ROI) does not include any portion of the greater trochanter
  2. Soft tissue is contained in both ends of the Neck Region of Interest
  3. The Neck Region of Interest (ROI) is perpendicular to the femoral neck.
  4. The Neck Region of Interest (ROI), ideally, does not contain any portion of the ischium. If the ischium is include in the Neck Region of Interest (ROI), the program automatically types the bone as Neutral.

Spine Scan

The technician adjusts the image so that the bone edges can be clearly seen and makes sure that the bone and tissue are correctly identified by the analysis software. The technician ensures the region of interest is correctly positioned as follows:

  1. Make sure the intervertebral markers are between the vertebral bodies
  2. Make sure the intervertebral markers are located at the lowest point of the bone density as indicated on the bone profile.

GE Lunar DXA systems and related software, such as enCORE, are under copyright. ©2010 General Electric Company. All rights reserved. GE and GE Monogram are trademarks of General Electric Company. GE Healthcare is a division of General Electric Company.

Protocol Name from Source:

The Expert Review Panel has not reviewed this measure yet.

Availability:

Publicly available

Personnel and Training Required

Technicians may or may not be certified radiology technologists depending on state laws. Regardless of formal education, study personnel should receive specialized training in the survey protocol and basic techniques of the operation of the specific make and model of the dual-energy X-ray absorptiometry (DXA) machine used.Device-specific education and training should be provided to the operators and interpreters prior to clinical use. Quality control procedures should be performed regularly.

Equipment Needs

Several dual-energy X-ray absorptiometry (DXA) machines are marketed commercially. According to the International Society for Clinical Densitometry (2007), "Bone density measurements from different devices cannot be directly compared." Because there are many manufacturers, models, and software versions of the DXA machine, investigators must report those they are using. Regular scans (i.e., weekly at a minimum for large studies) using DXA phantoms are recommended as an independent assessment of system calibration. Studies that use more than one scanner device should also implement a plan to monitor inter-scanner differences at baseline and at regular intervals during the study.

Note: Manufacturers of DXA equipment are constantly striving to improve and update both their equipment and software with the latest technological advances. The recommended equipment for this protocol in PhenX is current as of June 2009. Please refer to the DXA specifications for your model number to ensure that the level of information collected is compatible with the PhenX protocol.

Requirements
Requirement CategoryRequired
Major equipment Yes
Specialized training Yes
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual Yes
Mode of Administration

Noninvasive radiologic assessment

Life Stage:

Adult, Senior

Participants:

Adults, ages 18 years and older

Specific Instructions:

Given that there are multiple manufacturers and models of dual-energy X-ray absorptiometry (DXA) machines (each with associated software), investigators must report the equipment they are using and cannot directly compare bone density measurements from different DXA machines (per the International Society for Clinical Densitometry (2007) and Bonnick, S. L. (2009)). Additionally, weekly scans using DXA phantoms are recommended as an independent assessment of system calibration. Studies that use more than one DXA machine should also implement a plan to monitor inter-scanner differences at baseline and at regular intervals during the study. Additionally, for studies involving more than one technician, an average precision error that combines data from all of the technicians should be used to establish the least significant change (LSC) and the precision error for the DXA facility (per the International Society for Clinical Densitometry (2007)). Lastly, the precision error for technicians should be evaluated periodically, such as after they have received training on the specific DXA machine, have completed DXA scans on about 100 patients, if there has been a change in their skill level, or if a new DXA system is used (per the International Society for Clinical Densitometry (2007)).

Note: Manufacturers of DXA equipment are constantly striving to improve and update both their equipment and software with the latest technological advances. Hence, please refer to the DXA specifications for your model number to ensure that the level of information collected is compatible with the PhenX protocol.

Given that the selected protocol uses a GE Lunar densitometer©, the PhenX Skin, Bone, Muscle and Joint Working Group recommends that users of HologicTM densitometers find comparable protocols used by the National Health and Nutrition Examination Survey (NHANES).

DXA measurement is complex and requires costly hardware, specialized software to analyze the DXA scans, rigorous quality control, specialized examiners, continuous equipment calibration and monitoring, and scan quality control monitoring. Although excerpts of the procedure manual for the Framingham Osteoporosis Study Generation 3 Musculoskeletal Exam (May 2008–2010) protocol are provided for informational purposes, investigators should review all facets of the protocol prior to undertaking DXA examinations in a study.

Selection Rationale

The Framingham Osteoporosis Study Generation 3 Musculoskeletal Exam was selected as the best practice methodology for the determination of bone density at the hip and lower spine by dual-energy X-ray absorptiometry. The Framingham Heart Study is a long-running, large prospective cohort study to determine the characteristics that contribute to cardiovascular disease. The Framingham Heart Study has included an osteoporosis component since 1988.

Language

English

Standards
StandardNameIDSource
Common Data Elements (CDE) Bone Dual X-ray Absorptometry Femur Bone Density Assessment Score 3158227 CDE Browser
Common Data Elements (CDE) Bone Dual X-ray Absorptometry Vertebra Bone Density Assessment Score 3158231 CDE Browser
Logical Observation Identifiers Names and Codes (LOINC) Spine - femur bone density DXA proto 62910-5 LOINC
Derived Variables

None

Process and Review

The Expert Review Panel has not reviewed this measure yet.

Source

U.S. Department of Health and Human Services, National Institutes of Health, National Heart, Lung and Blood Institute, and Boston University. (May 2008–2010). Framingham Heart Study (FHS). Framingham Osteoporosis Study Generation 3 Musculoskeletal Exam manual. Rockville, MD: U.S. Department of Health and Human Services.

General References

International Society for Clinical Densitometry. (2007). Official positions and pediatric official positions of the International Society for Clinical Densitometry. Available at

http://www.iscd.org/Visitors/pdfs/ISCD2007OfficialPositions-Combined-AdultandPediatric.pdf.

Bonnick, S. L. (2009).Bone densitometry in clinical practice: Application and interpretation, 3rd ed. Humana Press.

Protocol ID:

170701

Variables:
Export Variables
Variable NameVariable IDVariable DescriptionVersiondbGaP Mapping
PX170701_Birth_Control PX170701070000 Did you use one of the following forms of birth control each time you had sexual intercourse in the past seven days? (Birth control methods not found on this list are not considered effective in preventing pregnancies by our study physicians.) 4 N/A
PX170701_DXA_Machine_Manufacturer PX170701080200 Dual-energy x-ray absorptiometry (DXA) manufacturer 4 N/A
PX170701_DXA_Machine_Name PX170701080100 Dual-energy x-ray absorptiometry (DXA) machine name 4 N/A
PX170701_Femur_Scan_ID PX170701090000 Femur scan image name (ID) 4 N/A
PX170701_Intercourse_In_Last_Week PX170701060000 Have you had sexual intercourse in the past seven days? 4 N/A
PX170701_Last_Menstrual_Period PX170701030100 If no, when was your last menstrual period? 4 N/A
PX170701_Pregnancy_Test_Required PX170701040000 Pregnancy Test Required? 4 N/A
PX170701_Pregnancy_Test_Result PX170701040100 If yes, Result: 4 N/A
PX170701_Pregnant PX170701010000 Are you pregnant? 4 Variable Mapping
PX170701_Spine_Scan_ID PX170701100000 Spine scan image name (ID) 4 N/A
PX170701_WomenOver55_Hysterectomy PX170701030000 For women >55 years old: Have you had a hysterectomy 4 N/A
PX170701_WomenUnder55_Hysterectomy_Tubal_Ligation PX170701020000 For women <55 years old: Have you had a hysterectomy [removal of the uterus] or tubal ligation [tubes tied]? 4 N/A
Research Domain Information
Measure Name:

Spine and Femur Bone Density by Dual-Energy X-ray Absorptiometry

Release Date:

November 12, 2010

Definition

This is a measure to obtain spine and femur dual-energy X-ray absorptiometry (DXA) scans to assess bone mineral density.

Purpose

Bone density (or bone mineral density; BMD) is a risk factor for fracture, and is often used to categorize individuals into disease categories such as osteoporosis or osteopenia.

Keywords

arthritis, dual-energy X-ray absorptiometry, DXA, X-rays, radiograph, body composition, bone density, bone mineral density, BMD, DEXA, osteoporosis, osteopenia, National Health and Nutrition Examination Survey, NHANES, The International Society for Clinical Densitometry, ISCD, Framingham Osteoporosis Study, Framingham Heart Study, FHS, Hologic