Lymphatics: Anatomy, Mapping, and Evolving Imaging Technologies
The lymphatic system is an intricate, hierarchically arranged network of vessels that is vital for interstitial uid balance (Shayan et al., 2006). The lymphatics also form part of the rst element of the body’s defences to interact with pathogens or malignant cells attempting to inltrate the peripheral tissues of the body (Kinmonth, 1972). Lymphatics are vital to cellular movement within the immune system (Johnson et al., 2006), but these lymphatic channels may be hijacked as potential routes of cancer spread and dissemination (Haagensen et al., 1972). They may also become compromised by acquired physical insults such as surgery or parasitic infection or be congenitally decient or defective at birth – all resulting in lymphoedema (Kinmonth, 1972). With improving technologies, researchers have been able to hone in on the intricacies of the microanatomy of the lymphatic vessel subtypes and differentiate these distinct vessel entities even further (Shayan et al., 2007, 2012). With this renement, the study of macro lymphatic vessel patterning and layout has become one of mapping drainage of vessels for that individual and in the particular area of the body in question (e.g. draining a tumour in a certain anatomical location), rather than a quest to describe a specic pattern of lymphatic vessels that may be generalised to a larger population. As discussed in Chapter 7, numerous techniques for injection and intra-operative mapping of lymphatic vessels have been described; these are not discussed in this chapter, which focuses exclusively on techniques for deriving an image of the lymphatic vessels.