ARRS 2022 Abstracts

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E2017. Quantitative CT for Bone Mineral Density Assessment
Authors
  1. Afshin Ameri; Tufts Medical Center
  2. Robert Ward; Tufts Medical Center
Background
The world health organization (WHO) promotes the use of dual-energy X-ray absorptiometry (DXA) to calculate a 2D areal bone mineral density (BMD) as a way of assessing fracture risk in post-menopausal women and men over the age of 50. Areal BMD is calculated using a superimposed cortical and trabecular BMD, and quantitative CT (qCT) allows for a volumetric calculation of trabecular BMD. This exhibit will review the indications for qCT over DXA and some of the potential advantages of the technique.

Educational Goals / Teaching Points
This exhibit will explain how qCT works, how are the images acquired, and what type of post-processing takes place. We will review different indications for qCT and potential clinical scenarios where it can be useful and demonstrate representative images from our center. Lastly, we will evaluate the strengths and weaknesses of qCT and how it compares to other techniques.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Trabecular bone, despite only accounting for 20% of bone mass, is responsible for most of the turnover; hence, trabecular fractures, such as vertebral compression fractures, account for most early osteoporotic fractures, whereas cortical fractures dominate at the later stages. In addition, degenerative changes, compression fractures, and extremes of body weights have all been reported in literature as culprits for false negative DXA results. Therefore, qCT can be of utility in all the aforementioned cases by focusing on trabecular BMD.

Conclusion
qCT should be considered over DXA for BMD assessment, in cases of advanced degenerative changes, vertebral compression fractures, extremes of body weight, early osteoporosis or need for sensitive BMD monitoring. However, its utility can be somewhat limited due to lack of a standardized way of interpreting the T scores.