Diffuse Optical Tomography

Concurrent MRI and diffuse optical tomography of breast after indocyanine green enhancement

Vasilis Ntziachristos*†‡, A. G. Yodh§, Mitchell Schnall¶, and Britton Chance†

Departments of *Bioengineering, †Biochemistry Biophysics, §Physics and Astronomy, and ¶Radiology, University of Pennsylvania, Philadelphia, PA 19104-6089 Contributed by Britton Chance, December 23, 1999

We present quantitative optical images of human breast in vivo. The images were obtained by using near-infrared diffuse optical tomography (DOT) after the administration of indocyanine green (ICG) for contrast enhancement. The optical examination was performed concurrently with a magnetic resonance imaging (MRI) exam on patients scheduled for excisional biopsy or surgery so that accurate image coregistration and histopathological information of the suspicious lesions was available. The ICG-enhanced optical images coregistered accurately with Gadolinium-enhanced magnetic resonance images validating the ability of DOT to image breast tissue. In contrast to simple transillumination, we found that DOT provides for localization and quantification of exogenous tissue chromophore concentrations. Additionally our use of ICG, an albumin bound absorbing dye in plasma, demonstrates the potential to differentiate disease based on the quantified enhancement of suspicious lesions.

optical properties contrast agents MRI coregistration

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iffuse optical tomography (DOT) in the near-infrared (NIR) is an emerging imaging modality with potential application in radiology. The technique has the capacity to produce quantitative images of intrinsic and extrinsic absorption and scattering (1–4), as well as fluorophore lifetime and yield (5–7) in diffuse media such as tissue. These fundamental quantities can then be used to derive tissue oxy- and deoxyhemoglobin concentrations, blood oxygen saturation (8), contrast agent uptake, and organelle concentration (9). Such novel contrast mechanisms are important for...