Standardized platform for coregistration of nonconcurrent diffuse optical and magnetic resonance breast images obtained in different geometries

Abstract

We present a novel methodology for combining breast image data obtained at different times, in different geometries, and by different techniques. We combine data based on diffuse optical tomography (DOT) and magnetic resonance imaging (MRI). The software platform integrates advanced multimodal registration and segmentation algorithms, requires minimal user experience, and employs computationally efficient techniques. The resulting superposed 3-D tomographs facilitate tissue analyses based on structural and functional data derived from both modalities, and readily permit enhancement of DOT data reconstruction using MRI-derived a-priori structural information. We demonstrate the multimodal registration method using a simulated phantom, and we present initial patient studies that confirm that tumorous regions in a patient breast found by both imaging modalities exhibit significantly higher total hemoglobin concentration (THC) than surrounding normal tissues. The average THC in the tumorous regions is one to three standard deviations larger than the overall breast average THC for all patients.

Diffuse optical tomography reconstruction method using ultrasound images as prior for regularization matrix

“…20 Implementation of spatially encoded regularization using images obtained from MRI was introduced and investigated, where two-step image reconstruction procedure is required. 21,22 In the first step, a suspicious lesion is segmented from the rest of the tissue. Then, this prior information is imposed to regularize the matrix inversion.…”

Mono- and multimodal registration of optical breast images

“…24 Optical breast image acquisition in these hybrid environments is often limited by the requirements of the other imaging modality. 81 For example, other imaging modalities may impose constraints on the acquisition geometry, the placement and configuration of sensors, as well as the materials of which the imaging apparatus is made. It is worth noting that these hybrid systems are often cost prohibitive and typically not available.…”

“…60,79,81,[87][88][89][90][91][92][93] For example, Brooksby et al 60,87,88 use MRI data to accurately define the imaging volume, regularize the reconstructed contrast to be optimal over an area of interest in the MR image deemed suspicious, and reduce the number of unknown parameters in the reconstruction by segmenting the tissue types visible in the MRI. Azar et al 81,[90][91][92][93] register nonconcurrent optical breast imaging and MRI to be used in reconstruction. Boverman et al 89 similarly used segmented MRI to guide reconstruction.…”

“…Another significant limitation of co-acquiring optical breast imaging and MRI is the inability to use ferro-magnetic instruments in MRI, thus requiring extensive customization of the optical breast imaging instrumentation. 81 …”

“…Azar et al have developed a general software package for automated registration between several modalities. 81,[91][92][93] They apply this method to optical breast imaging and MRI to produce fusion images showing structural and functional data and propose incorporating their registered MRI data into optical breast imaging reconstruction in future work. 81 They register the images by maximizing the mutual information of the images.…”