BMD-GAN: Bone mineral density estimation using x-ray image decomposition into projections of bone-segmented quantitative computed tomography using hierarchical learning

TL;DR

BMD-GAN is a novel method that estimates bone mineral density from plain x-ray images by decomposing them into projections of bone-segmented QCT, enabling accurate, opportunistic osteoporosis screening without large training datasets.

Contribution

The paper introduces BMD-GAN, a hierarchical GAN-based approach that accurately estimates BMD from x-ray images using QCT for training, reducing data requirements and enhancing extensibility.

Findings

Achieved a Pearson correlation coefficient of 0.888 with ground truth BMD.

Does not require large-scale training datasets.

Extensible to other anatomical regions.

Abstract

We propose a method for estimating the bone mineral density (BMD) from a plain x-ray image. Dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) provide high accuracy in diagnosing osteoporosis; however, these modalities require special equipment and scan protocols. Measuring BMD from an x-ray image provides an opportunistic screening, which is potentially useful for early diagnosis. The previous methods that directly learn the relationship between x-ray images and BMD require a large training dataset to achieve high accuracy because of large intensity variations in the x-ray images. Therefore, we propose an approach using the QCT for training a generative adversarial network (GAN) and decomposing an x-ray image into a projection of bone-segmented QCT. The proposed hierarchical learning improved the robustness and accuracy of quantitatively decomposing a small-area target. The evaluation of 200 patients with osteoarthritis using the proposed method, which we named BMD-GAN, demonstrated a Pearson correlation coefficient of 0.888 between the predicted and ground truth DXA-measured BMD. Besides not requiring a large-scale training database, another advantage of our method is its extensibility to other anatomical areas, such as the vertebrae and rib bones.