Current Status of Optical Imaging for Evaluating Lymph Nodes and Lymphatic System

Abstract

Optical imaging techniques use visual and near infrared rays. Despite their considerably poor penetration depth, they are widely used due to their safe and intuitive properties and potential for intraoperative usage. Optical imaging techniques have been actively investigated for clinical imaging of lymph nodes and lymphatic system. This article summarizes a variety of optical tracers and techniques used for lymph node and lymphatic imaging, and reviews their clinical applications. Emerging new optical imaging techniques and their potential are also described.

Photoacoustic Imaging for Differential Diagnosis of Benign Polyps versus Malignant Polyps of the Gallbladder: A Preliminary Study

“…Second, because this is an ex vivo study with surgical specimens, the practical application might still be limited, especially due to the relatively thick abdominal wall that PA waves need to pass through. However, PA imaging has a major advantage over existing optical modalities in optically scattering tissue, even when the imaging depth is beyond the optical mean free path ( 6 31 ). As an example, PA imaging of the human breast has recently been achieved with satisfactory spatial resolution at a depth of up to 5 cm from the skin surface ( 32 ).…”

OCT-based label-free in vivo lymphangiography within human skin and areola

“…There are no truly non-invasive ways to assess the in vivo status of tumor induced lymphangiogenesis and to monitor the treatment modalities on lymphatics. Currently, subdermal injection of contrast agents is required for imaging lymphatic vessels in clinics, but they can create complications in patients so it is considered as significantly invasive in the clinical care as well as in the clinical research 4 . Injection itself might also initiate an inflammatory response which in return affects the results.…”

“…Unfortunately, most of the existing contrast agents can be toxic and induce side effects to patients 3 . Moreover, locating and cannulating a lymphatic vessel can be significantly invasive for patients and very difficult in preclinical research using transgenic mouse models due to their small size 4 . X-ray 5 , magnetic resonance imaging 6 , near infrared fluorescence imaging 7 and lymphoscintigraphy 8 techniques provide a body imaging, albeit with poor resolution, so they are used for imaging the larger vessels and the lymph nodes.…”

Clinical use of organic near‐infrared fluorescent contrast agents in image‐guided oncologic procedures and its potential in veterinary oncology

“…NIR fluorescence imaging offers both transcutaneous and intraoperative visualisation of the afferent lymphatics and SLNs (Fig 4) with an equal or even slightly higher sensitivity than the combined use of lymphoscintigraphy and blue dyes 43 53 54 . This technique has been reported in preclinical and clinical studies as an attractive alternative for SLN mapping in patients with breast cancers, 33 43–45 55 cervical cancers, 46 56 malignant melanomas 54 and other types of cancer 49 51 57–59 .…”