Role of ultrasound measurements
in fracture risk assessment
2nd Strong Bone Asia, 2008
Assoc. Prof. Chatlert Pongchaiyakul, MD.
Division of Endocrinology and Metabolism,
Department of Medicine, Faculty of Medicine, KKU, THAILAND
Treatment
- Clinical risk factors
- Fracture risk assessment
tools
Diagnosis Osteoporosis :
WHO by DXA
Definition of Osteoporosis
Skeletal disorder characterized
by compromised bone strength
leading to an increased risk of fracture
Bone strength primarily reflects the
integration of bone density and bone quality
NIH Consensus Conference, 2000
BMD Assessment
•
•
•
•
•
•
Digital X-ray radiogrammetry (DXR)
Radiographic absorptiometry (RA)
Single photon absorptiometry (SPA)
Single energy X-ray absorptiometry (SXA)
Dual photon absorptiometry (DPA)
Dual energy X-ray absorptiometry / dual Xray absorptiometry (DXA)
• Quantitative computed tomography (QCT)
• Quantitative ultrasound (QUS)
BMD Assessment
•
•
•
•
•
•
Digital X-ray radiogrammetry (DXR)
Radiographic absorptiometry (RA)
Single photon absorptiometry (SPA)
Single energy X-ray absorptiometry (SXA)
Dual photon absorptiometry (DPA)
Dual energy X-ray absorptiometry / dual Xray absorptiometry (DXA)
• Quantitative computed tomography (QCT)
• Quantitative ultrasound (QUS)
10-year probabilities
by age and FNBMD T-score
Kanis JA, et al. Osteoporos Int 2001;12:989-95.
1 SD decrease:
Fracture risk increase
RR = 1.4-2.6
Cumming SR. JAMA 2002;288:1889-97
Sites of BMD
measurement
Wrist
fracture
Distal radius
Femoral neck
Lumbar spine
1.7 (1.4-2.0)
1.4 (1.4-1.6)
1.5 (1.3-1.8)
Hip
fracture
Vertebral
fracture
All fractures
1.8 (1.4-2.2) 1.7 (1.4-2.1)
2.6 (2.0-3.5) 1.8 (1.1-2.7)
1.6 (1.2-2.2) 2.3 (1.9-2.8)
1.4 (1.3-1.6)
1.6 (1.4-1.8)
1.5 (1.4-1.7)
Marshall D. BMJ 1996;312:1254-9.
BMD by DXA
Advantage
• Gold standard
• Prediction fracture
• Monitoring
Disadvantage
• Expensive & Maintenance
• High costs
• Limit resource
• Well-trained technician
• Not portable
Fracture Rates, Population T-Score Distribution
and Number of Fractures in NORA
Wainwright SA. J Clin Endocrinol Metab 2005;90(5):2787-93
Quantitative Ultrasound
Advantage
• Portable
• Less expensive and 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)
Types of ultrasound transmission
• Trabecular transverse transmission:
calcaneus (water-based and dry system)
• Cortical transverse transmission:
phalanges
• Cortical axial transmission:
phalanges, metacarpals, radius, tibia
Quantitative Ultrasound Techniques
Transmission of Signal
Receipt of Signal
t (time)
w (width)
SOS = w/t
• Speed of Sound (SOS)
• Broadband Ultrasound
Attenuation (BUA)
• Stiffness Index (SI)
= (0.67 x BUA)+(0.28 x SOS) - 420
• Quantitative Ultrasound
Index (QUI)
= 0.41×(BUA + SOS) – 571
• Amplitude dependent
speed of sound (AD-SOS)
Quantitative Ultrasound Techniques
• Speed of Sound (SOS)
• Broadband Ultrasound
Attenuation (BUA)
• Stiffness Index (SI)
= (0.67 x BUA)+(0.28 x SOS) - 420
• Quantitative Ultrasound
Index (QUI)
= 0.41×(BUA + SOS) – 571
• Amplitude dependent
speed of sound (AD-SOS)
Correlation between QUS parameters and
trabecular structure in human cancellous bone
Calcaneus1
BQ
BV/TV
Tb.Th
Tb.Sp
Tb.N
Vertebral body2
BUA
SOS
BUA
SOS
0.78
0.82
-0.70
0.65
0.79
0.82
-0.75
0.67
0.72
0.52
-0.74
0.73
0.67
0.48
-0.66
0.66
QUS can assess bone quality
and bone architecture.
1 Hans
D. Bone 1995;16:295-300.
2Nicholson
PH. Bone 1998;23:425-31.
Correlations between QUS and DXA
measurements
QUS calcaneus
(BUA, SOS, SI,
QUI)
Calaneus
BMD
LS
BMD
FN
BMD
total hip
BMD
0.58-0.80
0.3-0.5
0.7-0.8
0.5-0.6
He YQ, et al. Osteoporos Int 2000;11:354-60.
Schneider J, et al. Calcif Tissue Int 2004;74:246-54.
Greenspan SL, et al. Osteoporos Int 2001;12:391-8.
Gnudi S, et al.Ultrasound Med Biol 2004;30:357-61.
Can QUS be used to diagnose osteoporosis ?
• The WHO diagnostic classification cannot be
applied to T-scores from measurements other
than DXA at the femoral neck, total femur,
lumbar spine or one-third (33%) radius because
those T-scores are not equivalent to T-scores
derived by DXA. (good, grade A, worldwide)
ISCD 2007: Position Statement
Krieg et al. The ISCD 2007 Official Positions. JCD2008;11:163-87
Estimate of the average T-score
at the age of 65 in women
Measurement
Sites
Technique
T-score at age
65 years
Spine
Spine
Heel
Spine
Forearm
Femoral neck
Total hip
Heel
QCT
Lateral DXA
Achilles
DXA
DXA
DXA
DXA
Sahara
-2.5
-2.2
-1.5
-1.3
-1.4
-1.2
-0.9
-0.7
Kanis JA. Osteoporos Int 2001; 192-202.
Krieg et al. The ISCD 2007 Official Positions. JCD2008;11:163-87
Sensitivity and Specificity for different QUS T-Scores
Nakak S, Ann Intern Med. 2006;144:832-841.
QUS and
Osteoporosis prediction
56.7 (OR: 43.7)
50
40
21.4 (OR: 9.1)
14.3 (OR: 5.6)
30
20
0
Low risk
(>-1)
<-2.5
QUS
o
>-2.5
f calc
aneu
s (T-
re
2.9
High risk
(<-1)
Sc
o
10
OS
TA
steoporosis
o
f
o
e
c
n
le
a
v
Pre
by DXA (%)
60
scor
e)
Figure 1. Prevalence of osteoporosis (by DXA) according to
QUS of calcaneus and OSTA score
Pongchaiyakul C. J Med Assoc Thai 2007; 90(10):2016-23.
58.6 (OR: 60.9)
60
50
40
16.7 (OR: 8.6)
20.7 (OR: 11.2)
30
20
10
2.3
High risk
(<-1)
0
QUS
of
>-2.5
calca
neus
KK
OS
Low risk
(>-1)
<-2.5
Sc
or
e
osteoporosis
f
o
e
c
n
le
a
v
re
P
by DXA (%)
70
(T-sc
ore)
Figure 2. Prevalence of osteoporosis (by DXA) according to
QUS of calcaneus and KKOS score
Pongchaiyakul C. J Med Assoc Thai 2007; 90(10):2016-23.
Female: 70 yr, 50 kg, QUS T-score = -3 SD
48+67+78 =193
48
67
193
Pongchaiyakul C, et al. Osteoporos Int 2007;18:525-31.
~0.5
78
Can QUS be used for fracture risk assessment?
ISCD 2007: Position Statement
• The only validated skeletal site for the clinical use of
QUS in osteoporosis management is the “heel”.
(good, grade A, Worldwide)
• Heel QUS predicted fragility fracture in
postmenopausal women (hip, vertebral, and global
fracture risk) and men >65 yr (hip and all non-verterbral
fractures), independently of central DXA BMD.
(good, grade A, Worldwide)
Krieg et al. The ISCD 2007 Official Positions. JCD2008;11:163-87
4
3
Relative risk for hip fractures
EPIDOS study
2
2.0
1
0
BUA
4
3
SOS
FN-BMD
Relative risk for non-spinal fractures
SOF study
1.5
Relative risk for hip fractures
SOF study
1.0
BUA
Cal-BMD FN-BMD
2
1
0
BUA
SOS
FN-BMD
EPIDOS: Hans D. Lancet 1996;348:511-4.
SOF: Bauer DC. Arch Int Med 1997;157:629-34.
Major cross-sectional studies of QUS in
hip fracture prediction
Krieg et al. JCD2008;11:163-87
Major cross-sectional studies of QUS in
vertebral fracture prediction
Krieg et al. JCD2008;11:163-87
Summary of prospective studies of QUS in
osteoporotic fracture prediction
Krieg et al. JCD2008;11:163-87
QUS and Fracture Prediction by Devices
and by Types of Fractures
Krieg et al. JCD2008;11:163-87
QUS and Fracture Prediction by Devices
and by Types of Fractures
Krieg et al. JCD2008;11:163-87
Krieg et al. JCD2008;11:163-87
RR AND 95% CI OF LOW-ENERGY TRAUMA FRACTURES FOR 1 SD DECREASE
IN THE QUS PARAMETERS IN WOMEN
Site of
fracture
QUS
parameter
Site of
measurement
RR
(95%CI)
Any site
BUA
SOS
Calcaneus
All sites
Calcaneus
Calcaneus
Calcaneus
All sites
Calcaneus
Calcaneus
Calcaneus
Calcaneus
Calcaneus
1.74 (1.38-2.21)
1.73 (1.38-2.17)
1.71 (1.28-2.29)
1.66 (1.39-1.99)
1.23 (1.10-1.38)
1.43 (1.22-1.67)
1.90 (1.47-2.45)
1.71 (1.21-2.42)
1.94 (1.46-2.59)
QUI
Non-spinal
Hip
Martin F. J Bone Miner Res 2006;21:1126–35.
BUA
SOS
QUI
BUA
SOS
QUI
Gradient of risk (RR/SD) for BUA and SOS in women with
and without adjustment for BMD
Without BMD
Variables
BUA
BUA
BUA
SOS
Peripheral BMD
Outcome
fracture
Any
Osteoporotic
Hip
Hip
Any
Osteoporotic
Hip
With BMD
RR/SD
95%CI
RR/SD
95%CI
1.40
1.25-1.58
1.22
1.06-1.41
1.40
1.26-1.56
1.20
1.06-1.36
1.72
1.52-1.95
1.40
1.22-1.61
1.51
1.33-1.71
1.24
1.09-1.40
1.30
1.22-1.39
1.35
1.25-1.45
1.30
1.15-1.48
Johnell O, Kanis JA. WHO. Geneva 2007. (www.who.int/chp/topics/rheumatic/en/index.html)
Case-finding strategy if DXA is not available
Postmenopausal women
CRFs + Heel QUS
assessment
Low probability
of fracture
Medium probability
of fracture
High probability
of fracture
Central DXA assessment
according to WHO criteria
Primary
prevention
Treatment
initiation
Conclusion
• Osteoporosis & Fracture: Burden in Asian population
• BMD by DXA: gold standard..but have some limitations
• QUS: alternative method…
- inexpensive, portable, radiation-free
- proven to predict hip fractures and all osteoporotic
fractures
- different technologies
- need specific guideline
Strong Bone Asia