Optical Biopsy of Lymph Node Morphology using Optical Coherence Tomography

Abstract

Optical diagnostic imaging techniques are increasingly being used in the clinical environment, allowing for improved screening and diagnosis while minimizing the number of invasive procedures. Diffuse optical tomography, for example, is capable of whole-breast imaging and is being developed as an alternative to traditional X-ray mammography. While this may eventually be a very effective screening method, other optical techniques are better suited for imaging on the cellular and molecular scale. Optical Coherence Tomography (OCT), for instance, is capable of high-resolution cross-sectional imaging of tissue morphology. In a manner analogous to ultrasound imaging except using optics, pulses of near-infrared light are sent into the tissue while coherence-gated reflections are measured interferometrically to form a cross-sectional image of tissue. In this paper we apply OCT techniques for the high-resolution three-dimensional visualization of lymph node morphology. We present the first reported OCT images showing detailed morphological structure and corresponding histological features of lymph nodes from a carcinogen-induced rat mammary tumor model, as well as from a human lymph node containing late stage metastatic disease. The results illustrate the potential for OCT to visualize detailed lymph node structures on the scale of micrometastases and the potential for the detection of metastatic nodal disease intraoperatively.

Imaging of Human Lymph Nodes Using Optical Coherence Tomography: Potential for Staging Cancer

“…It is conceptually similar to ultrasound, but uses reflections of low-power, near-IR light instead of sound waves. OCT has the potential to provide in vivo assessment of lymph node involvement and preliminary work has shown images of a human cervical lymph node specimen (10). The use of OCT may avoid unnecessary excision of benign, uninvolved nodes, and reduce the incidence of lymphedema.…”

Mapping Tissue Optical Attenuation to Identify Cancer Using Optical Coherence Tomography

“…It is conceptually similar to ultrasound, but uses reflections of low-power, near-infrared light instead of sound waves. It is capable of imaging tissue with a resolution of approximately 10 microns, and has the potential to assess lymph node involvement in cancer in vivo [3]. However, the signal values in an OCT data set are not determined absolutely by the tissue.…”

Front Matter: Volume 7139

“…This was evidenced as dark spots (high reflection) further into the A-scan. This artefact can also be seen in the images of [9]. The mechanism for this effect has not yet been verified and will require further investigation.…”

“…It has been used to obtain high-resolution images of the structural changes caused by cancer in the gastrointestinal tract [4][5], breast [6], biliary system [7] and cervix [8]. Recently, Luo et al [9] proposed using OCT in the assessment of axillary lymph nodes. OCT provides the possibility of an imaging-based optical biopsy method for determining lymph node involvement.…”