Emerging lymphatic imaging technologies for mouse and man

Abstract

The lymphatic circulatory system has diverse functions in lipid absorption, fluid homeostasis, and immune surveillance and responds dynamically when presented with infection, inflammation, altered hemodynamics, and cancer. Visualization of these dynamic processes in human disease and animal models of disease is key to understanding the contributory role of the lymphatic circulatory system in disease and to devising effective therapeutic strategies. Longitudinal, non-destructive, and repeated imaging is necessary to expand our understanding of disease progression and regression in basic science and clinical investigations. Herein we summarize recent advances in in vivo lymphatic imaging employing magnetic resonance, computed tomography, lymphoscintigraphy, and emerging optical techniques with respect to their contributory roles in both basic science and clinical research investigations.

Lymphatic function measurements influenced by contrast agent volume and body position

“…This research focus has catalyzed the advancement of techniques used to assess lymphatic function (7), including near-infrared fluorescence (NIRF) imaging, direct fluorescence imaging of lymphatic contraction, and Doppler optical coherence tomography (DOCT) (8)(9)(10). NIRF imaging is used both preclinically and clinically to visualize how injected NIR contrast agents -frequently the FDA-approved molecule indocyanine green (ICG) -move though lymphatic vessels (11)(12)(13). A region of interest (ROI) on the vessel is used to measure the changes in intensity that likely correspond to lymphatic contraction and/or movement of lymph fluid (14).…”

Characterization of internodal collecting lymphatic vessel function after surgical removal of an axillary lymph node in mice

“…However, no studies have shown how post-nodal collecting lymphatic vessels draining to the surgical wound area change functionally and architecturally in response to axillary lymphadenectomy. In this study, we used dual-wavelength fluorescence imaging with injection of two different lymphatic mapping agents, Alexa-680-bovine serum albumin (BSA) and ICG, both of which have been used for lymphatic imaging [9,10]. Unlike other imaging modalities, such as magnetic resonance imaging (MRI) and positron emission tomography (PET), fluorescence optical imaging allows simultaneous visualization of lymphatic vessels in different regions due to a distinct spectral wavelength emitted from each injected fluorophore.…”

Thoracic involvement in generalised lymphatic anomaly (or lymphangiomatosis)

“…In the future, near-infrared fluorescence lymphatic imaging, nanotechnology-based MRI agents, and gene reporter technologies may represent new tools for studying the structure and function of the lymphatic system [58].…”