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Interpretation of DXA Scans

Deborah Sellmeyer, MDProfessor of Medicine

Division of Endocrinology, Gerontology, and Metabol ismStanford University, School of Medicine

DXA Technology

X-ray Source (two energies with different attenuation profiles)

Collimator (pinhole for pencil beam, slit for fan beam)

Patient

Detector (detects 2 tissue types - bone and soft tissue)

Very low radiation to patient.

Very little scatter radiation to technologist

Lumbar Spine Positioning

• Straight spine

• Equal soft tissue on both sides of vertebra

• Correct labeling

• No artifacts

Hip Positioning• Femoral shaft vertical

• Small amount lesser trochanter

• Rotation decreases lesser trochanter and apparent femoral neck BMD

• No ischium in femoral neck ROI

Femoral Neck ROI different between Hologic and GE Lunar

GE Lunar

Hologic

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Hip PositioningDXA #1Name, contact info for facility Name, contact info for facility

Patient NameMed Record numberDOB

Patient NameMed Record numberDOB

Demo-graphics

DateSoftware

TechnologistMachine

Measured directly

Calculated =BMC (g)

area (cm2)

T-score = SD’s above (+) or below (-) young reference population

Z-score = SD’s above or below age matched reference population

Referencepopulation

DXA #2

T-score-0.9-1.5-0.7-2.2-1.4

Z-score

0.90.51.4-0.00.7

BMD(g/cm2)0.8260.8601.0030.8690.892

Region

L1L2L3L4

Total

T-score-1.8-0.7

Z-score-0.10.7

Region

NeckTotal

BMD(g/cm2)0.6590.871

DXA #3

T-score-1.3-1.5-3.4-2.4-2.2

Z-Score

Region

L1L2L3L4

Total

BMD(g/cm2)0.7780.8580.7110.8480.800

T-score-2.8-2.6

Z-Score

Region

NeckTotal

BMD(g/cm2)0.5410.622

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DXA #4

T-score-5.2-5.3-5.3-4.6-5.1

Z-score-3.5-3.5-3.4-2.5-3.2

BMD(g/cm2)0.3530.4400.4960.6150.490

Region

L1L2L3L4

Total

T-score-3.6-3.6

Z-Score-2.0-2.3

Region

NeckTotal

BMD(g/cm2)0.4480.497

DXA #5

T-score-2.6-2.9-3.2-3.4-3.1

Z-score-1.6-1.8-2.0-2.2-1.9

BMD(g/cm2)0.6380.7040.7340.7430.709

Region

L1L2L3L4

Total

T-score-2.5-2.2

Z-Score-1.4-1.5

Region

NeckTotal

BMD(g/cm2)0.5740.677

DXA #6

T-score

0.71.21.21.51.1

Z-score

1.62.22.32.62.2

BMD(g/cm2)1.0001.1641.2181.2781.171

Region

L1L2L3L4

Total

T-score-0.20.5

Z-Score

0.81.2

Region

NeckTotal

BMD(g/cm2)0.8221.005

DXA #7

BMD(g/cm2)0.8911.0431.0711.1401.046

Region

L1L2L3L4

Total

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DXA #8

April 2017

DXA #9

T-score-8.5-8.5

Z-score-7.4-7.4

BMD(g/cm2)0.0520.052

Region

L1Total

Jan 2014 DXA: Lumber spine (L1-L4) BMD is 0.762 g/cm2, with a T-score of -2.6.

April 2017

DXA #9

T-score-8.5-8.5

Z-score-7.4-7.4

BMD(g/cm2)0.0520.052

Region

L1Total

DXA #10

T-score-2.6-2.9

Z-Score

Region

NeckTotal

BMD(g/cm2)0.5820.573

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DXA #11

0 10 20 30 40 50 60 70

BON

E MASS

AGE

50% during adolescence

Using pediatric reference, Z-score = -0.1

http://www.bcm.edu/bodycomplab/mainbodycomp.htm

T-score-2.6-2.9

Z-Score

Region

NeckTotal

BMD(g/cm2)0.5820.573

DXA #12

GE Lunar

Hologic

DXA #13

Hologic

GE Lunar

DXA #14

2017

2016T-

score-2.8-1.8

Z-Score-1.5-0.8

Region

NeckTotal

BMD(g/cm2)0.5390.726

T-score-2.3-1.6

Z-Score-0.9-0.6

Region

NeckTotal

BMD(g/cm2)0.5950.745

Change (%)

10.4%

T-score-2.3-2.8

Scan Date

May 2017Jan 2016

BMD(g/cm2)0.5950.539

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DXA #15

Change (%)

-9.7%

T-score-3.2-2.6

Scan Date

Oct 2009Oct 2007

BMD(g/cm2)0.6900.764

Change (%)

13.7%

T-score-0.9-1.7

Scan Date

Oct 2009Oct 2007

BMD(g/cm2)0.8290.729

DXA #15

T-score-2.2-2.5-2.4-3.1-2.6

Z-score-1.3-1.4-1.3-1.9-1.5

BMD(g/cm2)0.6790.7550.8200.7780.764

Region

L1L2L3L4

Total

T-score-2.9-3.1-3.4-3.5-3.2

Z-score-1.8-1.9-2.1-2.1-2.0

BMD(g/cm2)0.6750.6860.7140.6810.690

Region

L1L2L3L4

Total

2007 2009

DXA #15

T-score-2.4-0.9

Z-Score-1.2-0.1

Region

NeckTotal

BMD(g/cm2)0.5870.829

T-score-1.6-1.7

Z-Score-0.5-1.0

Region

NeckTotal

BMD(g/cm2)0.6750.729

2007 2009

DXA #16

T-score-3.0-1.9

Z-Score-2.3-1.4

Region

NeckTotal

BMD(g/cm2)0.5170.713

T-score-3.1-2.6

Z-Score-2.4-2.2

Region

NeckTotal

BMD(g/cm2)0.5080.625

97 x 96NECK 49 x 15

97 x 115NECK 48 x 15

2014 2015

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Aug 2018 Aug 2018

DXA #17

T-score-1.4-1.8-2.4-2.0

Z-score

0.70.70.10.4

BMD(g/cm2)0.8350.8900.7940.834

Region

L1L3L4

Total

T-score-2.6-1.9

Z-Score-0.5-0.2

Region

NeckTotal

BMD(g/cm2)0.5650.710

Change (%)

9.1%

T-score-2.0-2.6

Scan Date

Aug 2018Aug 2013

BMD(g/cm2)0.8340.764

Change (%)

-10.6%

T-score-1.9-1.2

Scan Date

Aug 2018Aug 2013

BMD(g/cm2)0.7100.795

Aug 2018

DXA #17

T-score-1.4-1.8-2.4-2.0

Z-score

0.70.70.10.4

BMD(g/cm2)0.8350.8900.7940.834

Region

L1L3L4

Total

Change (%)

9.1%

T-score-2.0-2.6

Scan Date

Aug 2018Aug 2013

BMD(g/cm2)0.8340.764

Aug 2013

T-score-2.7-2.8-2.7-2.3-2.6

Z-score-0.9-0.7-0.6-0.1-0.6

BMD(g/cm2)0.6950.7250.7820.8110.757

Region

L1L2L3L4

Total

Aug 2018

DXA #17

T-score-2.6-1.9

Z-Score-0.5-0.2

Region

NeckTotal

BMD(g/cm2)0.5650.710

Change (%)

-10.6%

T-score-1.9-1.2

Scan Date

Aug 2018Aug 2013

BMD(g/cm2)0.7100.795

Aug 2013

T-score-1.7-1.2

Z-Score

0.10.3

Region

NeckTotal

BMD(g/cm2)0.6610.795

Aug 2018Aug 2013

DXA #17

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DXA #18

June 2019

April 2018

Lumbar spine

April 2018

Lumbar spine

June 2019

DXA #18

April 2018

June 2019

DXA #18DXA #19

183.2

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DXA #19

183.2

111.1

DXA #19

Radius styloid process excluded

Ultradistal line where radius and ulna meet

1/3 forearm site determine by radius length

Size of ROI boxROI should extend beyond soft tissue

DXA #20

2014

Correct positioning

ROI box too high

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2015

DXA #21

Correct positioning

Did not measure forearm.

ROI too short

185x77

228x91

DXA #22

2017

T-score-3.2

Z-Score-2.1

Radius

1/3

BMD(g/cm2)0.503

Change (%)

-21.1%

T-score-3.2-0.9

Scan Date

March 2017July 2015

BMD(g/cm2)0.5030.638

DXA #22

2015

2017

T-score-3.2

Z-Score-2.1

Radius

1/3

BMD(g/cm2)0.503

T-score-0.9

Z-Score-0.0

Radius

1/3

BMD(g/cm2)0.638

228x84

228x84

DXA #23

T-score-6.8

Z-Score-3.5

Radius

1/3

BMD(g/cm2)0.289

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Questions?