A novel visualization method for the ribs within chest volume data

摘要

The ribs within computed tomography (CT) images form curved structures intersecting the axial plane at oblique angles. Rib metastases and other pathologies of the rib are apparent in CT images. Analysis of the ribs using conventional 2D axial slice viewing involves manually tracking them through multiple slices. 3D visualization of the ribs also has drawbacks due to occlusion. Examination of a single rib may require repositioning the viewpoint several times in order to avoid other ribs. We propose a novel visualization method that eliminates rib curvatures by straightening each rib along its centerline. This reduces both 2D and 3D viewing complexities. Our method is based upon first segmenting and extracting the centerlines of each rib. These steps are done through a tracing based segmentation. Next, the centerlines are refined to a smoother contour. Each centerline is then used to resample and digitally straighten each rib. The result is a simplified volume containing only the straightened ribs, which can be quickly examined both in 3D and by scrolling through a series of about 40 slices. Additionally, a projection of the image can yield a single 2D image for examination. The method was tested on chest CT images obtained from patients both positive and negative for rib metastases. Running time was less than 15 seconds per dataset. Preliminary results demonstrate the effectiveness of the visualization in detecting and delineating these metastases.