Multiple registration of coronal and sagittal MR temporal image sequences based on Hough transform

This work discusses the use of breathing patterns present in time sequences of MR images in the temporal registration of coronal and sagittal images. The registration is done without the use of any triggering information and any special gas to enhance the contrast. The temporal sequences of images are acquired in free breathing. As coronal and sagittal sequences of images are orthogonal to each other, their intersection corresponds to a segment in the three dimensional space. The registration happens by analyzing this intersection segment that is determined by a coronal-sagittal mapping. A time sequence of this intersection segment can be stacked, defining a two dimension spatio-temporal (2DST) image. It is assumed that the diaphragmatic movement is the principal movement and all the lungs structures do move almost synchronously. The synchronization was realized through a pattern named respiratory function. A Hough transform algorithm, using the respiratory function as input, searches for synchronized movements with the respiratory function. Finally, the composition of coronal and sagittal images that are in the same breathing phase is made by comparison of diaphragmatic respiratory patterns. Several results and conclusions are shown.