Elastic matching of dynamic MR mammographic images.

Dynamic magnetic resonance imaging (MRI) carried out with paramagnetic contrast media has been proven to increase sensitivity and specificity in the detection of breast cancer. Due to movements of the patients and changes in the shape of the breasts during the measurement period, a coregistration (matching) of the acquired data volumes is necessary to obtain higher accuracy for the localization of lesions. In this study, an algorithm for the elastic matching of dynamic MRI volume data is presented. The approach includes automatic feature extraction along with the analysis of corresponding features between the data sets. The matching is actually slice-oriented, even though information on displacement vectors in adjacent slices is taken into account. An extension of the procedure to fully three-dimensionally (3D) matching is straight forward. Up until now, the approach has been applied to 20 dynamic MRI studies. The matching time for two image data sets with 256 x 256 x 15 voxels each was about 4 min using a PC (Pentium Pro, 200MHz).