SPINE Volume 47, Number 24, pp E628
© 2022 Wolters Kluwer Health, Inc. All rights reserved.
LETTER
TO THE
EDITOR
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TO THE EDITOR:
Concerning the Article: Should Q-CT Be the Gold
Standard for Detecting Spinal Osteoporosis?
A
rvind compared the T-scores of the bone densities
measured by two different methods: spinal quantitative computed tomography (QCT) and dual-x ray
absorptiometry (DXA). The diagnostic criteria recommended by the WHO in 1994 was used to establish the
diagnosis of osteoporosis (normal, −1.0 or above; osteopenia, between −1.0 and −2.5; osteoporosis, −2.5 or below).
The author concluded that QCT provides more precise
estimation of cancellous bone mineral density (BMD) than
DXA. We would like to comment on the most relevant
shortcomings.
The T = −2.5 criterion introduced by WHO is primarily
based on the relationship between forearm BMD (tested by
DXA) and prevalent hip fracture. It is inappropriate to use a
−2.5 T-score for different measurement techniques.1
Instead, the following diagnostic cut points may be used
for assigning a spine QCT (normal, BMD > 120 mg/cm3;
osteopenia, 80 mg/cm3 ≤ BMD ≤ 120 mg/cm3; osteoporosis, BMD <80 mg/cm3).2 A DXA T-score of −2.5 would
correspond to an equivalent QCT T-score of −3.4 using
reference data published for the scanner manufacturer
(Siemens) and analysis mode.3 For these reasons, Arvind
assigning a T = −2.5 diagnostic category based on a QCT
spine T-score will likely result in overestimating osteoporosis patients.
Wentao Lin, MM
Zhiyun Wang, MD
Shunde Hospital, Southern Medical University
(The First People’s Hospital of Shunde Foshan), Foshan,
Guangdong, China
dragon201@126.com
References
1. Faulkner KG, von Stetten E, Miller P. Discordance in patient
classification using T-scores. J Clin Densitom. 1999;2:343–50.
2. American College of Radiology. Acr–Spr–Ssr Practice Parameter for
The Performance of Musculoskeletal Quantitative Computed
Tomography (QCT). 2018.
3. Engelke K, Adams JE, Armbrecht G, et al. Clinical use of
quantitative computed tomography and peripheral quantitative
computed tomography in the management of osteoporosis in
adults: the 2007 ISCD Official Positions. J Clin Densitom.
2008;11:123–62.
DOI: 10.1097/BRS.0000000000004502
E628
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