Research on Three-dimensional Cartilage Thickness Measurement of Femoral Head in Magnetic Resonance Images

Measuring the thickness of articular cartilage in three-dimensional (3D) magnetic resonance (MR) images is an important diagnostic procedure. A 3D measuring method was proposed to determine the femoral cartilage thickness in this paper. The cartilage thickness was defined as the distance between the two sides of the edges, which are the zero-crossing points of the second directional derivatives combined with Gaussian blurring along the normal direction of the cartilage surface. The spherical constraint of the femoral shape was utilized to confirm the normal direction. The zero-crossing method was demonstrated by mathematical simulation. Experiments were conducted using a resected femoral head to validate the method. The anatomical thickness data were proved to be well correlated with the zero-crossing thickness data.