Correlation between the individual LSC and the institute average LSC for serial bone mineral density assessments
Keywords:
Precision, Serial BMD, Least significant changeAbstract
Objective: To evaluate the correlation between an individual LSC average and an institutual
LSC for serial bone mineral density assessments.
Design: Between June and September 2014, a cross-sectional study was conducted using DXA
scans of 120 bone mineral density results from participants at Burapha University Hospital. We
analyzed the individual LSC and the institute LSC averages. We then sent the collected data
for interpretation by radiologists to determine the percent of change in bone mineral density
across the 120 samples. We evaluated the correlation of both individual and institutional LSC
with a correlation percentage and kappa analysis.
Result: The institute average LSC at lumbar spine, femoral neck, total hip and distal 1/3 radius
were 3.20%, 2.91%, 2.73%, and 3.01%, respectively. The correlation of two methods between
four technologists was different (p<0.05). The density of the total hip showed the highest
accuracy of interpretation, with the institute average LSC (95.2%; 95%CI 89.9 - 100.0), followed
by the femoral neck results (80.6%; 95%CI 70.8 - 90.4). The lumbar spine and forearm results
showed moderate accuracy (75.8%; 95%CI 65.1 - 86.5 and 77.4%; 95%CI 67.0 - 87.8).
Conclusions: The use of the institutional LSC average resulted in an uncertain interpretation
because the correlation percentage was different across the four technologists and all
measurement sites. If the institute has many technologists, make sure that the institutional LSC
average presents more than 80% accuracy of interpretation in all measurement sites, before
using the institutional average LSC, instead of the individual LSC.
References
monitoring, technical aspects of DXA BMD
measurement and precision testing. Bone.
2017; 104: 44-53.
2. 2019 ISCD Official Positions – adult
[Internet]. 2019 [accessed December 27,
2019]. Available from: https://www.iscd.
org/official-positions/2019-iscd-officialpositions-adult/
3. Baim S, Wilson CR, Lewiecki EM, Luckey
MM, Downs RW Jr, Lentle BC. Precision
assessment and radiation safety for dualenergy X-ray absorptiometry: position paper
of the International Society for Clinical
Densitometry.J Clin Densitom. 2005; 8:
371-8.
4. Lewiecki EM, Lane NE. Common mistakes
in the clinical use of bone mineral density
testing. Nat Clin Pract Rheumatol. 2008; 4:
667-74.
5. International Atomic Energy Agency. Dual
energy X Ray Absorbtiometry for bone
mineral density and body composition
assessment. [Internet]. 2010 [accessed
April 29, 2018]. Available from: https
HYPERLINK “https://www-pub.iaea.org/
MTCD/Publications/PDF/Pub1479_web.
pdf”.
6. Bonnick SL, Lewis LA. Bone densitometry for
technologists: The Importance of precision.
3rded.New York: Springer Science+Business
Media; 2013: 163-82.
7. Kim HS, Yang SO. Quality control of
DXA system and precision test of radiotechnologists. J Bone Metab. 2014; 21: 2-7.
8. Lewiecki EM, Binkley N, Morgan SL,
Shuhart CR, Camargos BM, Carey JJ, et
al. Best practices for dual-energy x-ray
absorptiometry measurement and
reporting: International Society for Clinical
Densitometry Guidance. J Clin Densitom.
2016; 19: 127-40.
9. Nelson L, Gulenchyn KY, Atthey M, Webber
CE. Is a fixed value for the least significant
change appropriate? J Clin Densitom. 2010;
13: 18-23. doi: 10.1016/j.jocd.2009.10.001.
10.Kiebzak GM, Morgan SL. Long-term versus
short-term precision of dual-energy x-ray
absorptiometry scans and the impact on
interpreting change in bone mineral density
at follow-up. J Clin Densitom. 2011; 14:
108-15.
