The integration of automatic segmentation and motion tracking for 4D reconstruction and visualization of musculoskeletal structures

The 3D reconstruction of high contrast anatomical structures has been widely explored. However, a class of important clinical problems involves the motion of very complex musculoskeletal structures including the joints, hence a 4D reconstruction is desired. Practical difficulties with 4D reconstruction with MRI include the time required for data acquisition, the resolution required for visualization of small but critical structures, the gross inhomogeneities of field coil response, the degree of noise present with the signal and the extreme low-contrast details between some distinct anatomical structures. The authors present a comprehensive approach to 4D musculoskeletal imagery that address the above challenges. Specific MRI imaging protocols; segmentation, motion estimation and motion tracking algorithms are developed and applied to render complex 4D musculoskeletal systems. Applications of the approach include the analysis of the rotation of the upper arm and the knee extension.