Radiographic features such as femoral cortex thickening have been frequently observed with atypical subtrochanteric fractures. These features may be a valuable finding to help prevent fractures before they happen. The current practice of manual measurement is often subjective and inconsistent. We developed a semi-automatic tool to consistently measure and monitor the progress of femoral cortex thickening on radiographs. By placing two seed points on each side of the femur, the program automatically extracts the periosteal and endosteal layers of the cortical shell by active contour models and B-spline fitting. Several measurements are taken along the femur shaft, including shaft diameter, cortical thickness, and integral area for medial and lateral cortex. The experiment was conducted on 52 patient datasets. The semi-automatic measurements were validated against manual measurements on 52 patients and demonstrated great improvement in consistency and accuracy (p<0.001).
4D (3D + time) model is valuable in comprehensive assessment of cardiac functions. Usually, the generation of the 4D
myocardial models involves myocardium segmentation, mesh generation and non-rigid registration (to build mesh node
correspondence). In this paper, we present a method to simultaneously perform the above tasks. This method begins from
a triangular surface model of the myocardium at the first phase of a cardiac cycle. Then, the myocardial surface is
simulated as a linear elastic membrane, and evolves toward the next phase governed by an energy function while
maintaining the mesh quality. Our preliminary experiments performed on dynamic CT images of the dog demonstrated
the effectiveness of this method on both segmentation and mesh generation. The minimum average surface distance
between the segmentation results of the proposed method and the ground truth can reach 0.72 ± 0.55 mm, and the mesh
quality measured by the aspect ratio of the triangle was less than 11.57 ± 1.18.