2,242 research outputs found
Osteoporotic and Neoplastic Compression Fracture Classification on Longitudinal CT
Classification of vertebral compression fractures (VCF) having osteoporotic
or neoplastic origin is fundamental to the planning of treatment. We developed
a fracture classification system by acquiring quantitative morphologic and bone
density determinants of fracture progression through the use of automated
measurements from longitudinal studies. A total of 250 CT studies were acquired
for the task, each having previously identified VCFs with osteoporosis or
neoplasm. Thirty-six features or each identified VCF were computed and
classified using a committee of support vector machines. Ten-fold cross
validation on 695 identified fractured vertebrae showed classification
accuracies of 0.812, 0.665, and 0.820 for the measured, longitudinal, and
combined feature sets respectively.Comment: Contributed 4-Page Paper to be presented at the 2016 IEEE
International Symposium on Biomedical Imaging (ISBI), April 13-16, 2016,
Prague, Czech Republi
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A multi-center milestone study of clinical vertebral CT segmentation
A multiple center milestone study of clinical vertebra segmentation is presented in this paper. Vertebra segmentation is a fundamental step for spinal image analysis and intervention. The first half of the study was conducted in the spine segmentation challenge in 2014 International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI) Workshop on Computational Spine Imaging (CSI 2014). The objective was to evaluate the performance of several state-of-the-art vertebra segmentation algorithms on computed tomography (CT) scans using ten training and five testing dataset, all healthy cases; the second half of the study was conducted after the challenge, where additional 5 abnormal cases are used for testing to evaluate the performance under abnormal cases. Dice coefficients and absolute surface distances were used as evaluation metrics. Segmentation of each vertebra as a single geometric unit, as well as separate segmentation of vertebra substructures, was evaluated. Five teams participated in the comparative study. The top performers in the study achieved Dice coefficient of 0.93 in the upper thoracic, 0.95 in the lower thoracic and 0.96 in the lumbar spine for healthy cases, and 0.88 in the upper thoracic, 0.89 in the lower thoracic and 0.92 in the lumbar spine for osteoporotic and fractured cases. The strengths and weaknesses of each method as well as future suggestion for improvement are discussed. This is the first multi-center comparative study for vertebra segmentation methods, which will provide an up-to-date performance milestone for the fast growing spinal image analysis and intervention
Cube-Cut: Vertebral Body Segmentation in MRI-Data through Cubic-Shaped Divergences
In this article, we present a graph-based method using a cubic template for
volumetric segmentation of vertebrae in magnetic resonance imaging (MRI)
acquisitions. The user can define the degree of deviation from a regular cube
via a smoothness value Delta. The Cube-Cut algorithm generates a directed graph
with two terminal nodes (s-t-network), where the nodes of the graph correspond
to a cubic-shaped subset of the image's voxels. The weightings of the graph's
terminal edges, which connect every node with a virtual source s or a virtual
sink t, represent the affinity of a voxel to the vertebra (source) and to the
background (sink). Furthermore, a set of infinite weighted and non-terminal
edges implements the smoothness term. After graph construction, a minimal
s-t-cut is calculated within polynomial computation time, which splits the
nodes into two disjoint units. Subsequently, the segmentation result is
determined out of the source-set. A quantitative evaluation of a C++
implementation of the algorithm resulted in an average Dice Similarity
Coefficient (DSC) of 81.33% and a running time of less than a minute.Comment: 23 figures, 2 tables, 43 references, PLoS ONE 9(4): e9338
Vertebral body segmentation with GrowCut: Initial experience, workflow and practical application
In this contribution, we used the GrowCut segmentation algorithm publicly
available in three-dimensional Slicer for three-dimensional segmentation of
vertebral bodies. To the best of our knowledge, this is the first time that the
GrowCut method has been studied for the usage of vertebral body segmentation.
In brief, we found that the GrowCut segmentation times were consistently less
than the manual segmentation times. Hence, GrowCut provides an alternative to a
manual slice-by-slice segmentation process.Comment: 10 page
Mid-sagittal plane and mid-sagittal surface optimization in brain MRI using a local symmetry measure
This paper describes methods for automatic localization of the mid-sagittal plane (MSP) and mid-sagittal sur-face (MSS). The data used is a subset of the Leukoaraiosis And DISability (LADIS) study consisting of three-dimensional magnetic resonance brain data from 62 elderly subjects (age 66 to 84 years). Traditionally, the mid-sagittal plane is localized by global measures. However, this approach fails when the partitioning plane between the brain hemispheres does not coincide with the symmetry plane of the head. We instead propose to use a sparse set of profiles in the plane normal direction and maximize the local symmetry around these using a general-purpose optimizer. The plane is parameterized by azimuth and elevation angles along with the distance to the origin in the normal direction. This approach leads to solutions confirmed as the optimal MSP in 98 percent of the subjects. Despite the name, the mid-sagittal plane is not always planar, but a curved surface resulting in poor partitioning of the brain hemispheres. To account for this, this paper also investigates an opti-mization strategy which fits a thin-plate spline surface to the brain data using a robust least median of squares estimator. Albeit computationally more expensive, mid-sagittal surface fitting demonstrated convincingly better partitioning of curved brains into cerebral hemispheres. 1
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