Abstract
Purpose
To propose a fully automated deep learning (DL) framework for the vertebral morphometry and Cobb angle measurement from three-dimensional (3D) computed tomography (CT) images of the spine, and validate the proposed framework on an external database.
Methods
The vertebrae were first localized and segmented in each 3D CT image using a DL architecture based on an ensemble of U-Nets, and then automated vertebral morphometry in the form of vertebral body (VB) and intervertebral disk (IVD) heights, and spinal curvature measurements in the form of coronal and sagittal Cobb angles (thoracic kyphosis and lumbar lordosis) were performed using dedicated machine learning techniques. The framework was trained on 1725 vertebrae from 160 CT images and validated on an external database of 157 vertebrae from 15 CT images.
Results
The resulting mean absolute errors (± standard deviation) between the obtained DL and corresponding manual measurements were 1.17 ± 0.40 mm for VB heights, 0.54 ± 0.21 mm for IVD heights, and 3.42 ± 1.36° for coronal and sagittal Cobb angles, with respective maximal absolute errors of 2.51 mm, 1.64 mm, and 5.52°. Linear regression revealed excellent agreement, with Pearson’s correlation coefficient of 0.943, 0.928, and 0.996, respectively.
Conclusion
The obtained results are within the range of values, obtained by existing DL approaches without external validation. The results therefore confirm the scalability of the proposed DL framework from the perspective of application to external data, and time and computational resource consumption required for framework training.
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Notes
DSC is a standard metric for segmentation performance, computed as a double of the ratio of the achieved and reference segmentation overlap in pixels against the total number of pixels of both segmentations. As such, it is equal to the harmonic mean of the binary classification precision and recall, i.e., the F1 score.
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Acknowledgements
This research was financially supported by the Analytical Center for the Government of the Russian Federation (Agreement No. 70-2021-00143 01.11.2021). The funding sources did not influence this investigation or affect the outcomes and results.
Funding
Analytical Center for the Government of the Russian Federation, 70-2021-00143 01.11.2021, Bulat Ibragimov
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Alukaev, D., Kiselev, S., Mustafaev, T. et al. A deep learning framework for vertebral morphometry and Cobb angle measurement with external validation. Eur Spine J 31, 2115–2124 (2022). https://doi.org/10.1007/s00586-022-07245-4
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DOI: https://doi.org/10.1007/s00586-022-07245-4