Image-guided optical spectroscopy provides molecular-specific information in vivo: MRI-guided spectroscopy of breast cancer hemoglobin, water, and scatterer size

Abstract

A multimodality instrument that integrated optical or near-infrared spectroscopy into a magnetic resonance imaging (MRI) breast coil was used to perform a pilot study of image-guided spectroscopy on cancerous breast tissue. These results are believed to be the first multiwavelength spectroscopic images of breast cancer using MRI-guided constraints, and they show the cancer tumor to have high hemoglobin and water values, decreased oxygen saturation, and increased subcellular granularity. The use of frequency-domain diffuse tomography methods at many wavelengths provides the spectroscopy required for recovering maps of absorbers and scattering spectra, but the integration with MRI allows these data to be recovered on an image field that preserves high resolution and fuses the two data sets together. Integration of molecular spectroscopy into standard clinical MRI can be achieved with this approach to spectral tomography.

Integration of microwave tomography with magnetic resonance for improved breast imaging

“…We have experience at Dartmouth with multimodality combinations involving diffuse light in the near-infrared, termed Near InfraRed Spectral Tomography (NIRST), and have developed platforms with breast x-ray tomosynthesis 51,52 and MR. 53,54 Similar to MT, NIRST alone provides molecular specificity in terms of intrinsic breast tissue composition, but at poor spatial resolution, and when used in combination is significantly advantaged by the high-resolution spatial information provided by traditional breast imaging. The most robust and diagnostically significant NIRST parameter has been total hemoglobin concentration, Hb T , evidently because it is a surrogate for localized vascular density and associated angiogenic activity in cancers.…”

Recent advances in the development of Raman spectroscopy for deep non‐invasive medical diagnosis

“…Subsequent studies of this group led to the demonstration of 3D tomographic imaging-maps of phantoms and canine hind limb sections (with skin and tissue thickness of up to 45 mm) [38]. Further refinement of the reconstructed images was achieved by Srinivasan et al [39] (see Figure 3) who introduced image-guided Raman spectroscopy, a technique where X-ray CT images of the tissue are used to guide the numerical recovery of Raman images [40]. The method yielded a contrast ratio of 145 : 1 between the cortical bone and background.…”

A microcomputed tomography guided fluorescence tomography system for small animal molecular imaging

“…In this work, the customized instrumentation was designed to allow fully noncontact parallel detection of the Fl and Tr measurements to resolve these data acquisition issues. Studies of a priori approaches to diffuse tomography have been ongoing for sometime, 12,20,21 with promising results shown for imaging of breast cancers [22][23][24] and small animals. 25 Yet diffuse imaging is plagued by low resolution recovery of the interior because the reconstruction problem is an ill-posed inversion problem.…”