Skull-Stripping Method for Brain MRI Using a 3D Level Set with a Speedup Operator

Purpose: To extract the brain region from brain magnetic resonance (MR) images using a fast 3D level set method and a refinement process. Materials and Methods: The proposed method introduces a speedup operator to the conventional 3D level set method in order to accelerate the level set evolution. While the processing lime for brain extraction is reduced by the speedup operator, the accuracy of brain extraction is also improved by adopting a refinement process. Results: The speedup operator yielded a 75% reduction in the total iteration numbers for the synthesized volume. The proposed method was applied to several datasets and compared with previous methods, le, Brain Visa, BET, and Free Surfer. The proposed method provided a Jaccard index of 0.971 +/- 0.0114 for the Brain Web dataset, 0.864 +/- 0.035 for the IBSR dataset, and 0.9414 +/- 0.0517 for a self-produced dataset acquired with a 3T MRI system. Conclusion: Utilizing a speedup operator, the proposed method reduced the evolution time. Robust and accurate results for various datasets were obtained in experiments.