In order to run the example code, you will need some additional MATLAB functions. You can download the additional tools here:
In the archived file, you will find some debugging tools and common functions needed for typical MR reconstructions.
Nonrigid Motion Correction in 3D: Autofocusing
Because of the lengthy duration of typical MR scans, data acquired are sensitive to motion effects. There has been a lot of research on methods to minimize these motion artifacts – from prospective to retrospective methods. We wanted to focus on a method that can be generalized to any sequence. Thus, we worked on correcting for these artifacts retrospectively during the reconstruction process.
In order to do so, we looked into autofocusing (autocorrection). Some work has been published on this idea for the application of motion correction. By localizing the autofocusing process, we extend the concept to nonrigid motion artifacts. In order to make the algorithm computationally feasible, we limit the search space to motion paths to be linear paths collected with multi-channel receivers. The motion paths were estimated from navigator data collected using the Butterfly modification.
More details of the pulse sequence design and algorithm can be found in the references.
Fast Field Inhomogeneity and Concomitant Gradient Field Correction for Spiral Imaging
This is an older project, but I would like to eventually open my code for this project in hopes that someone might find this work useful.