Bone Density Measurement Normal Normal Osteoporosis Osteoporosis - - PowerPoint PPT Presentation

Normal Normal Osteoporosis Osteoporosis

Bone Density Measurement

Chalermchai Apinyanurug

National Osteoporosis Foundation North American Menopause Society American Association of Clinical Endocrinolgist

• All women age ≥ 65 yr
• Younger PM women

with ≥ 1 risk factor

• PM women who

present with fractures

• All women age ≥ 65 yr
• All women with

medical causes of bone loss

• Younger PM women

with ≥ 1 risk factor

• All women age ≥ 65 yr
• All women age ≥ 40 yr

who have sustained a fracture unrelated to major trauma

• All peri- and PM

women who have risk factors for fracture or bone loss

Who should receive BMD testing?

Indications for Bone Mineral Density (BMD) Testing From ISCD 2006

• Women aged 65 and older, Men aged 70 and older
• Postmenopausal women under age 65 with risk factors
• 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
• r bone loss
• Anyone being considered for pharmacologic therapy
• Anyone being treated, to monitor treatment effect
• Anyone 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

Densitometry Technologies

Central BMD Measurements

– QCT – DEXA

Peripheral BMD Measurements

– Conventional X-ray – RA – radiographic absorptiometry – X-Ray Radiogrammetry – Ultrasonometry – Peripheral DEXA

Routine radiographic

–Low Radiation dose –Insensitive: bone loss is apparent only after a 30% loss

• measures the optical

density

• small, inexpensive
• fingers only
• poor hip fracture prediction

Radiographic Absorptiometry

• Width of cortical bone in fingers

using standard x-ray

• Can be added to existing mammo /

x-ray system (need computer and scanner)

• fingers only
• poor hip fracture prediction

Radiogrammetry

QCT : Quantitative CT

Disadvantage

• High radiation dose
• Less precise than DXA (2-5%)
• Large accuracy errors (15%)
• Expensive

Quantitative Ultrasound of Calcaneus

Advantage

• Portable
• Low costs
• Less time-consuming
• No radiation
• No need well-trained technician
• May predict fracture

Disadvantage

• Not a gold standard
• Diagnostic performance

(High specificity but low sensitivity)

Investigations of osteoporosis : Update 2007

What’s new in DXA equipment's?

New Detector : Direct-Digital Cadmium Zinc Telluride (CZT) Better image quality Low X-ray exposure High accuracy and precision

New technique : One Positioning

One Position, 3 Scans

• AP Spine
• Left Femur
• Right Femur

Old

New DXA equipment : Better Image Quality

New

New DXA equipment : Better Image Quality

Old New

New Asian Reference Database

• China
• Korea
• Indonesia
• Japan
• Thai

New software : Computer Assisted Densitometry

• Automatic verification

– Positioning – Bone edges – Analysis regions – Artifacts

• Clinical Benefits

– Reduce errors – Better scan evaluation

• BMD results

– Previous results – Reference Data Comparison – Trending – Bone strength assessments

• Hip Axis Length
• Femur Strength Index

New Report

New Hip Assessment

• Hip Axis Length
• Upper Neck
• Dual femur study
• Femur Strength Index

“A Better Way to Look at the Femur”

Osteoporosis International. January, 2006

Dual Femur study : Improved Diagnosis and Treatment Decisions

American Society for Bone and Mineral Research : ASBMR 2005

Femur Strength Index

• 2,506 women. > 50 yr.
• significant predictors of hip fracture
• Power for predicting fracture was improved by

combining T-score, FSI, and HAL compared with T- score alone.

Osteoporosis International. January, 2006

Body Composition Methods

Underwater Weighing (Hydrodensitometry) DXA (Dual-energy X-Ray Absorptiometry) BIS Near Infrared Interactance Air Displacement Imaging Methods (CT, MRI) Anthropometry BIA (Bioelectrical Impedance Analysis)

Body Composition with DXA

• Directly measures fat, lean, and bone mass
• Monitoring impact of treatment and exercise/diet

regimens.

• Android/Gynoid Ratio identifies women

with cardiovascular disease

• Better than cholesterol, better than

triglycerides

Body Composition and Cardiovascular Disease

Ragi et al. ASBMR 2005

Estimated Total Body % Fat from Spine and Femur Scans

ASBMR 2005

Osteoporosis

Normal Bone Mass

Low Bone Mass (Osteopenia)

• 4.0 -3.5 -3.0 -2.5
• 2.0 -1.5 -1.0
• 0.5 0 +0.5 +1.0

Assessment of Fracture Risk and Its Application to Screening For Postmenopausal Osteoporosis WHO Study group; 1994.

Interpreting T-scores (WHO)

Correlates With Lifetime Fracture Risk for Caucasian Women

Clinical Risk Score

Index value = 0.2 x (weight - age), then drop the decimal digit

Osteoporosis Self-Assessment Tool for Asians (OSTA) Research Group Osteoporos Int 2001;12:699-705

Osteoporosis Self-Assessment Tool for Asians (OSTA)

OSTA index ≤ -1: High risk > -1: Low risk

• 21 clinics, 8 countries: 860 PM women
• 59% Chinese, 18% Korean, 11% Thai, 8% Filipinos,

4% Indian, Malay and others OSTA index < -4: High risk

• 1 to -4 : Medium risk

> -1: Low risk

Countries N Age Sens Spec PPV Filipinos

1465 40-89 90 66 23

Singapore

135 57-80 97 43 34

Thai

Khon Kaen Songkhla 322 388 45-84 43-91 97 93 (93) 54 61 (30) 21 24 (15)

Original

860 45-88 91 45 21

Chinese

722 1127 1101 43-81 88 54 34

Japanese

47-91 90 38-43 NA

Korean

48-87 87 67 24

Validation of OSTA in Asians

Sens: Sensitivity, Spec: Specificity, PPV: Positive predictive value

Khon Kaen Osteoporosis Study (KKOS) scoring system

Age (y) Score Weight (kg) Score < 45 45 - 49 50 - 54 55 - 59 60 - 64 65 - 69 70 - 74 75 - 79 80 - 84 85 – 89 > 90 + 7.5 + 6.0 + 4.5 + 3.0 + 1.5

• 1.5
• 3.0
• 4.5
• 6.0
• 7.5

< 30 30 - 34 35 - 39 40 - 44 45 - 49 50 - 54 55 - 59 60 - 64 65 - 69 70 - 74 75 - 79 80 - 84 85 - 89 > 90

• 14
• 12
• 10
• 8
• 6
• 4
• 2

+ 2 + 4 + 6 + 8 + 10 + 12

KKOS score

• high risk ≤ -1
• low risk > -1

Sensitivity 86% Specificity 65%

1- Specificity

Sensitivity

AUC 0.85

Pongchaiyakul C. J Med Assoc Thai 2004;87:910-6.

Probability (%) of having osteoporosis for a given Age and Body weight

Weight (kg) < 45 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85-89 > 90

< 30 58.7 67.4 75.0 81.3 86.3 90.2 93.0 95.1 96.6 97.6 98.3 30-34 47.5 56.8 65.6 73.5 80.1 85.4 89.5 92.5 94.7 96.3 97.4 35-39 36.6 45.6 54.9 63.8 71.9 78.8 84.4 88.7 91.9 94.3 96.0 40-44 26.9 34.8 43.6 52.9 62.0 70.3 77.5 83.3 87.9 91.3 93.9 45-49 19.0 25.4 33.0 41.7 51.0 60.2 68.7 76.1 82.2 87.0 90.7 50-54 13.0 17.8 23.9 31.3 39.8 49.0 58.3 67.0 74.6 81.0 86.1 55-59 8.7 12.1 16.7 22.5 29.7 38.0 47.1 56.4 65.2 73.1 80.0 60-64 5.7 8.1 11.3 15.6 21.2 28.1 36.2 45.1 54.4 63.4 71.6 65-69 3.7 5.3 7.5 10.5 14.6 19.9 26.5 34.4 43.2 52.5 61.6 70-74 2.4 3.4 4.9 7.0 9.8 13.7 18.7 25.0 32.6 41.3 50.5 75-79 1.5 2.2 3.2 4.6 6.5 9.2 12.8 17.5 23.6 30.9 39.4 80-84 1.0 1.4 2.1 3.0 4.2 6.0 8.5 11.9 16.4 22.2 29.3 85-89 0.6 0.9 1.3 1.9 2.7 3.9 5.6 7.9 11.1 15.4 20.9 > 90 0.4 0.6 0.8 1.2 1.8 2.5 3.6 5.2 7.4 10.4 14.4

Age (yr)

High risk Intermediate risk Low risk

10 20 30 40 50 60

Prevalence of osteoporosis by DXA (%) OSTA Score QUS of calcaneus (T-score)

<-2.5 >-2.5 Low risk (>-1) High risk (<-1)

Figure 1. Prevalence of osteoporosis (by DXA) according to QUS of calcaneus and OSTA score

2.9 14.3 (OR: 5.6) 56.7 (OR: 43.7) 21.4 (OR: 9.1)

10 20 30 40 50 60 70

Prevalence of osteoporosis by DXA (%) KKOS Score QUS of calcaneus (T-score)

<-2.5 >-2.5 Low risk (>-1) High risk (<-1)

Figure 2. Prevalence of osteoporosis (by DXA) according to QUS of calcaneus and KKOS score

2.3 16.7 (OR: 8.6) 58.6 (OR: 60.9) 20.7 (OR: 11.2)

Osteoporosis International 2007;18(4):525-31.

QUS T-score (SD) Weight (kg) Age (yr)

• 4
• 3
• 2
• 1

50 0.49 0.33 0.20 0.12 0.07 55 0.59 0.43 0.28 0.17 0.10 60 0.68 0.53 0.37 0.23 0.14 65 0.77 0.63 0.47 0.32 0.19 70 0.83 0.72 0.57 0.41 0.27 75 0.88 0.79 0.67 0.51 0.35 80 0.92 0.85 0.75 0.61 0.45 85 0.94 0.90 0.82 0.70 0.55 50 0.28 0.17 0.10 0.05 0.03 55 0.37 0.24 0.14 0.08 0.04 60 0.47 0.32 0.20 0.11 0.06 65 0.57 0.41 0.27 0.16 0.09 70 0.67 0.51 0.36 0.22 0.13 75 0.75 0.62 0.45 0.30 0.18 80 0.82 0.71 0.56 0.40 0.25 85 0.87 0.78 0.65 0.50 0.34

50 kg 40 kg

Predicted probability of having osteoporosis for a given age, weight and QUS

QUS T-score (SD) Weight (kg) Age (yr)

• 4
• 3
• 2
• 1

50 0.49 0.33 0.20 0.12 0.07 55 0.59 0.43 0.28 0.17 0.10 60 0.68 0.53 0.37 0.23 0.14 65 0.77 0.63 0.47 0.32 0.19 70 0.83 0.72 0.57 0.41 0.27 75 0.88 0.79 0.67 0.51 0.35 80 0.92 0.85 0.75 0.61 0.45 85 0.94 0.90 0.82 0.70 0.55 50 0.28 0.17 0.10 0.05 0.03 55 0.37 0.24 0.14 0.08 0.04 60 0.47 0.32 0.20 0.11 0.06 65 0.57 0.41 0.27 0.16 0.09 70 0.67 0.51 0.36 0.22 0.13 75 0.75 0.62 0.45 0.30 0.18 80 0.82 0.71 0.56 0.40 0.25 85 0.87 0.78 0.65 0.50 0.34

50 kg 40 kg

Predicted probability of having osteoporosis for a given age, weight and QUS

Points

10 20 30 40 50 60 70 80 90 100

Age

35 45 55 65 75 85

Weight

95 90 85 80 75 70 65 60 55 50 45 40 35 30

QUS

4 3 2 1

• 1
• 2
• 3
• 4
• 5

Total Points

40 80 120 160 200 240 280

Linear Predictor

• 8
• 6
• 4
• 2

1 2 3 4 5

Risk of Osteoporosis

0.01 0.1 0.3 0.6 0.8 0.95 0.99

Female: 70 yr, 50 kg, QUS T-score = -3 SD

48 67 78

~0.5 48+67+78 =193

193

110

Female Age 70 yr BW 50 kg QUS T-sc = -3

Easy Nomogram

Risk of Osteoporosis

Risk of osteoporosis

0.3 0.1 0.05 0.01 0.6 0.8 0.9 0.99

0.5

QUS T-scores Clinical risk scores

Probability of Osteoporosis ~ 50%