Image registration for microwave tomography of the breast using priors from non-simultaneous previous magnetic resonance images

Microwave tomography (MT), a novel imaging modality in which the body is probed non-invasively using non-ionizing high-frequency radio-frequency waves, has shown promise for breast cancer screening and more recently for the monitoring of chemotherapy treatment. As an inherently low-resolution modality, it has been shown that prior structural information from another imaging modality, such as magnetic resonance imaging (MRI), can be used to improve the spatial resolution and quantitative accuracy of MT. In this paper, we show the results of a single-patient trial in which we co-register a non-simultaneous prior MRI with MT data acquired in a fluid bath. For the purposes of registration evaluation, two MRI images were acquired, one in air and one in fluid, and the registration errors were evaluated for manually selected internal image features, for a number of image registration algorithms.