Artikel
Assessment of the bone quality of vertebral bodies using computed tomography measured Hounsfield units
Beurteilung der Knochenqualität von Wirbelkörpern anhand von computertomographisch gemessenen Hounsfieldeinheiten
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Autoren
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Fabian Bünger
- Universitätsklinikum Jena, Klinik und Poliklinik für Neurochirurgie, Jena, Deutschland
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Falko Schwarz
- Universitätsklinikum Jena, Klinik und Poliklinik für Neurochirurgie, Jena, Deutschland
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Christian Senft
- Universitätsklinikum Jena, Klinik und Poliklinik für Neurochirurgie, Jena, Deutschland
| Veröffentlicht: | 4. Juni 2021 |
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Gliederung
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Objective: Nonspecific back pain due to vertebral fractures is the most common manifestation of osteoporosis. Due to the increasing age of patients, the evaluation of bone density is becoming more and more important, especially in preparation for spinal surgery. The aim of the study is to determine bone density using computed tomography (CT). Here care should be investigated a possible correlation of Hounsfield Units (HU) of CT with bone density values of a quantitative computed tomography (QCT).
Methods: The study is a monocentric, retrospective data analysis. We examined 1000 vertebral bodies from a total of 369 patients who received a CT of the thoracolumbar transition and the lumbar spine (L1-4) in the period from January 1, 2015 to February 15, 2019 and compared the HU with the values of a QCT. Using SPSS, a linear regression, the general estimation equation and the Wald Chi square test, a general equation for the calculation of the QCT values was established. This equation includes the following influencing factors: HU, contrast medium application, sex and age of the patients.
Results: In our work we could prove a significant correlation between the Hounsfield units of a CT of the lumbar spine and the corresponding QCT values. The application of contrast agent significantly influences the correlation of the HU and the QCT values (p < 0.001; Figure 1 [Fig. 1]). We also observed that the calculated QCT values are independent of patient gender (p < 0.942) and that patient age has no clinically relevant influence on the calculation of QCT values (-0.2HU/year, p < 0.003). Furthermore, we could not demonstrate differences in the correlation of the three measured levels (axial, sagittal, coronary) to the QCT values. Since the application of contrast agent has a significant influence on the correlation, we only used native CT (N = 902) to establish the equation. According to our data we were able to establish a calculation to approximate QCT from lumbar spine QCT = 17.8+ 0.7 * HU.
Conclusion: The conversion equation makes it possible to calculate bone density values without the need for an additional QCT, without further radiation exposure or costs, and thus to evaluate bone quality. The measuring method makes it possible to obtain additional information from computed tomography.
