Image Registration for Microwave Tomography of the Breast Using Priors From Nonsimultaneous Previous Magnetic Resonance Images

Abstract

Microwave imaging is a low-cost imaging method that has shown promise for breast imaging and, in particular, neoadjuvant chemotherapy monitoring. The early studies of microwave imaging in the therapy monitoring setting are encouraging. For the neoadjuvant therapy application, it would be desirable to achieve the most accurate possible characterization of the tissue properties. One method to achieve increased resolution and specificity in microwave imaging reconstruction is the use of a soft prior regularization. The objective of this study is to develop a method to use magnetic resonance (MR) images, taken in a different imaging configuration, as this soft prior. To enable the use of the MR images as a soft prior, it is necessary to register the MR images to the microwave imaging space. Registration fiducials were placed around the breast that are visible in both the MRI and with an optical scanner integrated into the microwave system. Utilizing these common registration locations, numerical algorithms have been developed to warp the original breast MR images into a geometry closely resembling that in which the breast is pendant in the microwave system.

A Multiplicative Regularizer Augmented With Spatial Priors for Microwave Imaging

“…As can be seen in Figure 1(h), the AMR-CSI (Type II) reconstruction is almost perfect, which is aligned with our speculation. 4 In the next step, we only provide partial (incomplete) SP to the inversion algorithms. The partial SP are illustrated in Figure 2(a) where it is clear that the SP have no knowledge of the inner dielectric cylinder.…”

“…These SP may come from a different higher-resolution imaging modality such as magnetic resonance imaging (MRI) [1] or ultrasound imaging [2], [3]. For example, in [4], an image registration approach was proposed to use MRI images in MWI reconstruction. In addition, a combined imaging technology named magnetic resonance microwave tomography was proposed in [1].…”

On the Use of Focused Incident Near-Field Beams in Microwave Imaging

“…This imaging tool has the potential to be utilized for different applications such as breast cancer detection, stroke diagnosis, through wall imaging, security screening, and industrial non-destructive evaluation [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. MWI can also be used in conjunction with other imaging tools, e.g., with magnetic resonance imaging or ultrasound tomography [ 11 , 12 , 13 ]. In addition, MWI can be performed in the time domain or frequency domain, with the latter being the focus of this paper.…”

Mathematical models for efficient medical electromagnetic tomography

“…In the proposed method, the MRI registered image is implemented as a priori to give the initial geometrical shape and dielectric properties of the stroke, inspired by the works in [46]- [59]. However, instead of the gradient-based EMT in these works that deal with pixel-based variables, the shape and dielectric properties of the stroke will be taken as some parameters.…”

“…IV-1a, before transferring the patient to ICU (the stroke-MRI takes less than an hour to be prepared). Though MRI cannot undertake monitoring due to the aforementioned reasons (safety, cost and computational time), the generated stroke-MRI image upon patient arrival can be properly aligned and registered in EMT algorithm [49], [59], where the dielectric properties of different tissues are available in [34] (this approach is usually referred to as EPT). The registered image, thus, can be adopted in…”