Vertebra-Focused Landmark Detection for Scoliosis Assessment

Abstract

Adolescent idiopathic scoliosis (AIS) is a lifetime disease that arises in children. Accurate estimation of Cobb angles of the scoliosis is essential for clinicians to make diagnosis and treatment decisions. The Cobb angles are measured according to the vertebrae landmarks. Existing regression-based methods for the vertebra landmark detection typically suffer from large dense mapping parameters and inaccurate landmark localization. The segmentation-based methods tend to predict connected or corrupted vertebra masks. In this paper, we propose a novel vertebra-focused landmark detection method. Our model first localizes the vertebra centers, based on which it then traces the four corner landmarks of the vertebra through the learned corner offset. In this way, our method is able to keep the order of the landmarks. The comparison results demonstrate the merits of our method in both Cobb angle measurement and landmark detection on low-contrast and ambiguous X-ray images. Code is available at: https: //github.com/yijingru/Vertebra-Landmark-Detection.

A Keypoint Transformer to Discover Spine Structure for Cobb Angle Estimation

“…Cobb angles are determined by keypoints of vertebrae. Consistent with the keypoint estimation strategy from previous work [18], every spine in an X-ray image consists of t vertebrae (17 in this task), each of which contains four keypoints (top-left, top-right, bottom-left, and bottom-right), therefore, t center points are used to separate vertebrae, then according to the location of each center point, corresponding four keypoints are calculated.…”

“…Consistent with the baseline cobb angle estimator [18], data augmentation includes cropping, random expansion, and contrast-brightness distortion. ResNet-34 with pre-trained weights is chosen as the baseline backbone, while HRNet-18 is integrated like ours.…”

Automatic Vertebrae Localization and Spine Centerline Extraction in Radiographs of Patients with Adolescent Idiopathic Scoliosis

“…Adolescent Idiopathic Scoliosis (AIS) is a structurally deviated, lateral and axially rotated deformity of the spine, a lifetime condition that usually arises in children or around puberty [1]. Conventional early detection, physical therapy and bracing would be preferred to increase the quality of life, reduce deformation and to prevent surgery.…”

2-step deep learning model for landmarks localization in spine radiographs

“…Moreover, the images were limited to the cervical region and the dataset was rather small, making this approach impractical in ordinary clinical settings. Other models were developed with the specific purpose of calculating spine angles such as the sacral slope (SS), the pelvic tilt (PT), www.nature.com/scientificreports/ the pelvic incidence (PI) in the sagittal plane and the Cobb angle in the coronal plane 10,11 . In 10 , the calculation of the angles was performed using only specific points detected by the deep learning model, implying that the model can be used only for specific angles.…”

“…In 10 , the calculation of the angles was performed using only specific points detected by the deep learning model, implying that the model can be used only for specific angles. In 11 , a model that calculates the position of the vertebral corners overcoming the limitations of 10 was developed. However, in both studies all the radiographs presented a standardized field of view, which avoided the problem of understanding which vertebrae were visible in each specific image.…”