A dual modality system for simultaneous monitoring of a bi-functional optical & MRI contrast agent for cancer detection

Introduction : Multi-modality imaging is becoming a trend in developing new generation in vivo imaging techniques for diagnosis [1]. MRI is a high resolution imaging modality, while optical imaging provides essential functional information such as oxygen saturation in the diseased tissue. In addition, when the contrast agent is administrated, the sensitivity and specificity for each imaging component can be improved. For example, dynamic contrast enhanced MRI (DCE-MRI) has been proven to be the most sensitive modality in detecting breast lesions [2]. On the other hand, ICG contrast enhanced optical imaging has shown to be able to effectively reveal the vascular structural in diseased tissue [3]. 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. Recently, our group has developed a hybrid MRI/DOT multi-modality imaging system [4]. This MF-DOT system is based on a unique design that incorporates a fully automated, MR-compatible, multi-frequency and multi-spectral DOT system that can acquire data up to 300MHz. In such a multi-modality system, each modality measures a different parameter set, which make it difficult to crossvalidate the parameters measured by different modalities. An alternative solution is using an agent that provides contrast for both optical and MRI simultaneously.