Four-dimensional Multimodality Image Registration Applied to Gated SPECT and Gated MRI

摘要

An automatic registration technique for gated cardiac SPECT to gated MRI is presented. Prior to registration, the MRI data set is subjected to a preprocessing technique that automatically isolates the heart. During preprocessing, voxels in the MRI volume are designated as either dynamic or static based on their change in intensity over the course of the cardiac cycle. This allows the elimination of the external organs in the MRI dataset, leaving the heart as the main feature of the volume. To separate the left ventricle (LV) from the remainder of the heart, optimal thresholding is used. A mutual-information-based algorithm is used to register the two studies. The registration technique was tested with fourteen patient data sets, and the results were compared to those of manual registration by an expert. The preprocessing step significantly improved the accuracy of the registration when compared to automatic registration performed without pre-processing.