A surface-projection MMI for the fusion of brain MR and SPECT images

Recently, maximization mutual information (MMI) of image intensities has been proposed as a new matching criterion for automated multimodality image registration. However, the success of the MMI relies on the similarity of the histogram distribution between the images to be fused. This condition is usually hard to be achieved in practical application. Besides, MMI is time consuming because it needs to find an optimal solution about six parameters (three for shifts and three for rotations) during the registration process. To improve the performance of traditional MMI, a novel scheme named Surface-Projection MMI algorithm (SP-MMI) is proposed here. SP-MMI is a two-stage registration algorithm included MMI of surface projection and the following MMI of axial plane. The experimental results, using MR and SPECT images, to confirm the good performance of the proposed method in comparison with the traditional MMI method are also included.