Vertebrae In CT Images Research Articles

Semantics and instance interactive learning for labeling and segmentation of vertebrae in CT images

Automatically labeling and segmenting vertebrae in 3D CT images compose a complex multi-task problem. Current methods progressively conduct vertebra labeling and semantic segmentation, which typically include two separate models and may ignore feature interaction among different tasks. Although instance segmentation approaches with multi-channel prediction have been proposed to alleviate such issues, their utilization of semantic information remains insufficient. Additionally, another challenge for an accurate model is how to effectively distinguish similar adjacent vertebrae and model their sequential attribute. In this paper, we propose a Semantics and Instance Interactive Learning (SIIL) paradigm for synchronous labeling and segmentation of vertebrae in CT images. SIIL models semantic feature learning and instance feature learning, in which the former extracts spinal semantics and the latter distinguishes vertebral instances. Interactive learning involves semantic features to improve the separability of vertebral instances and instance features to help learn position and contour information, during which a Morphological Instance Localization Learning (MILL) module is introduced to align semantic and instance features and facilitate their interaction. Furthermore, an Ordinal Contrastive Prototype Learning (OCPL) module is devised to differentiate adjacent vertebrae with high similarity (via cross-image contrastive learning), and simultaneously model their sequential attribute (via a temporal unit). Extensive experiments on several datasets demonstrate that our method significantly outperforms other approaches in labeling and segmenting vertebrae. Our code is available at https://github.com/YuZhang-SMU/Vertebrae-Labeling-Segmentation

A convenient and stable vertebrae instance segmentation method for transforaminal endoscopic surgery planning.

Transforaminal endoscopic surgery (TES) is effective for treatment of intervertebral disc-related diseases. To avoid injury to the critical structures, preoperative planning is required to find a safe working channel. Therefore, accurate patient-specific vertebral segmentation is important. The purpose of this work is to develop a convenient, stable and feasible lumbar vertebrae segmentation method for TES planning. Based on the chain structure of the spine, an interactive dual-output vertebrae instance segmentation network was designed to segment the specific vertebrae in CT images. First, an initialization locator module was set up to provide an initial locating box. Then the dual-output network was designed to segment two adjacent vertebrae inside the locating box. Finally, iteration was performed until all the expected vertebrae were segmented. Verification on reconstructed public dataset showed that the vertebral segmentation Dice coefficient was 96.8 ± 1.2% and average surface distance (ASD) was 0.25 ± 0.10mm. For intervertebral foramen (IVF) region, the Dice coefficient was 96.1 ± 1.5% and ASD was 0.29 ± 0.10mm. For IVF forming region, the Dice coefficient was 93.4 ± 3.1% and ASD was 0.28 ± 0.13mm. The evaluation on private dataset showed that more than 90% of the segmentation were suitable for TES planning. For IVF region, the Dice coefficient was 94.4 ± 1.8% and ASD was 0.71 ± 0.49mm. This work provides a convenient, stable and feasible segmentation method for lumbar vertebrae, IVF region, and IVF forming region. The segmentation can meet the requirement for TES planning.

Fully automated 3D segmentation and separation of multiple cervical vertebrae in CT images using a 2D convolutional neural network

Background and ObjectiveWe investigated a novel method using a 2D convolutional neural network (CNN) to identify superior and inferior vertebrae in a single slice of CT images, and a post-processing for 3D segmentation and separation of cervical vertebrae. MethodsThe cervical spines of patients (N == 17, 1684 slices) from Severance and Gangnam Severance Hospitals (S/GSH) and healthy controls (N == 24, 3490 slices) from Seoul National University Bundang Hospital (SNUBH) were scanned by using various volumetric CT protocols. To prepare gold standard masks of cervical spine in CT images, each spine was segmented by using conventional image-processing methods and manually corrected by an expert. The gold standard masks were preprocessed and labeled into superior and inferior cervical vertebrae separately in the axial slices. The 2D U-Net model was trained by using the disease dataset (S/GSH) and additional validation was performed by using the healthy control dataset (SNUBH), and then the training and validation were repeated by switching the two datasets. ResultsIn case of the model was trained with the disease dataset (S/GSH) and validated with the healthy control (SNUBH), the mean and standard deviation (SD) of the Dice similarity coefficient (DSC), Jaccard similarity coefficient (JSC), mean surface distance (MSD), and Hausdorff surface distance (HSD) were 94.37%% ± 1.45%, 89.47%% ± 2.55%, 0.33 ± 0.12 mm and 20.89 ± 3.98 mm, and 88.67%% ± 5.82%, 80.83%% ± 8.09%, 1.05 ± 0.63 mm and 29.17 ± 19.74 mm, respectively. In case of the model was trained with the healthy control (SNUBH) and validated with the disease dataset (S/GSH), the mean and SD of DSC, JSC, MSD, and HSD were 96.23%% ± 1.55%, 92.95%% ± 2.58%, 0.39 ± 0.20 mm and 16.23 ± 6.72 mm, and 93.15%% ± 3.09%, 87.54%% ± 5.11%, 0.38 ± 0.17 mm and 20.85 ± 7.11 mm, respectively. ConclusionsThe results demonstrated that our fully automated method achieved comparable accuracies with inter- and intra-observer variabilities of manual segmentation by human experts, which is time consuming.

腹部X線CT画像からの脊椎領域の抽出に関する基礎的検討(セッション4,学生研究発表会)

腹部X線CT画像からの脊椎領域の抽出に関する基礎的検討(セッション4,学生研究発表会)

A multi-scale method for automatically extracting the dominant features of cervical vertebrae in CT images

Localization of the dominant points of cervical spines in medical images is important for improving the medical automation in clinical head and neck applications. In order to automatically identify the dominant points of cervical vertebrae in neck CT images with precision, we propose a method based on multi-scale contour analysis to analyzing the deformable shape of spines. To extract the spine contour, we introduce a method to automatically generate the initial contour of the spine shape, and the distance field for level set active contour iterations can also be deduced. In the shape analysis stage, we at first coarsely segment the extracted contour with zero-crossing points of the curvature based on the analysis with curvature scale space, and the spine shape is modeled with the analysis of curvature scale space. Then, each segmented curve is analyzed geometrically based on the turning angle property at different scales, and the local extreme points are extracted and verified as the dominant feature points. The vertices of the shape contour are approximately derived with the analysis at coarse scale, and then adjusted precisely at fine scale. Consequently, the results of experiment show that we approach a success rate of 93.4% and accuracy of 0.37mm by comparing with the manual results.

Automated identification of thoracolumbar vertebrae using orthogonal matching pursuit

A computer-assisted system that can automatically provide rapid localization and accurate labeling of vertebral disks and bodies is a highly desirable tool due to the large demand for the diagnostic imaging and surgical planning of the vertebral column structures. However, a reliable detection and definitive labeling of vertebrae can be difficult due to factors such as the limited imaging coverage and various vertebral anomalies particularly in the thoracolumbar and lumbosacral junctions. In this paper, we investigate the problem of identifying the last thoracic and first lumbar vertebrae in CT images. The main purpose of this study is to improve the accuracy of labeling vertebrae of an automatic spine labeling system especially when the field of view is limited in the lower spine region. We present a dictionary-based classification method using a cascade of simultaneous orthogonal matching pursuit classifiers on 2D vertebral regions extracted from the maximum intensity projection images. The performance of the proposed method in terms of accuracy and speed has been validated by experimental results on hundreds of CT images collected from various clinical sites.

Automated model-based vertebra detection, identification, and segmentation in CT images

For many orthopaedic, neurological, and oncological applications, an exact segmentation of the vertebral column including an identification of each vertebra is essential. However, although bony structures show high contrast in CT images, the segmentation and labelling of individual vertebrae is challenging. In this paper, we present a comprehensive solution for automatically detecting, identifying, and segmenting vertebrae in CT images. A framework has been designed that takes an arbitrary CT image, e.g., head-neck, thorax, lumbar, or whole spine, as input and provides a segmentation in form of labelled triangulated vertebra surface models. In order to obtain a robust processing chain, profound prior knowledge is applied through the use of various kinds of models covering shape, gradient, and appearance information. The framework has been tested on 64 CT images even including pathologies. In 56 cases, it was successfully applied resulting in a final mean point-to-surface segmentation error of 1.12+/-1.04mm. One key issue is a reliable identification of vertebrae. For a single vertebra, we achieve an identification success of more than 70%. Increasing the number of available vertebrae leads to an increase in the identification rate reaching 100% if 16 or more vertebrae are shown in the image.