Validation of optical tomography in vivo

Introduction : Multi-modality imaging is becoming a trend in developing new generation in vivo imaging techniques for diagnosis [1]. Recently, our group has developed a high temporal resolution, dynamic MRI-DOT multi-modality imaging system [2]. Dynamic contrast enhanced MRI (DCEMRI) has been proven to be the most sensitive modality in detecting breast lesions [3]. However, it has low specificity in differentiating benign and malignant lesions. Meanwhile, diffuse optical tomography (DOT) is a recently emerging optical imaging technique that uses arrays of sources and detectors to obtain spatially dependent optical parameters of tissue. It can also provide enhancement kinetics of an FDA approved optical contrast agent (ICG). The enhancement kinetics of ICG may have a potential to distinguish between the malignant and benign tumors and hence, DOT may be used adjunct to MRI to improve the overall specificity. In general, each component of a multi-modality system measures a different parameter set, which makes it difficult to cross-validate the parameters measured by different modalities. In this study, however, we used a bi-functional agent that provides contrast for both optical and MR imaging to validate the optical molecular imaging system in vivo.