Ex vivo examination of cervical lymph nodes using multispectral optoacoustic tomography – a feasibility study

Introduction Multispectral optoacoustic tomography (MSOT) is an imaging technique in which tissue is illuminated with pulsed laser light at different wavelengths. The light is absorbed dependently in the tissue. Transient heating/thermoelastic expansion produces pressure waves that are detected by ultrasound receivers. In this feasibility study, the investigability of neck lymph nodes ex vivo using MSOT will be tested.

Material & Methods Evaluation of hybrid scans (ultrasound and MSOT) on extirpated lymph nodes using "MSOT Acuity Echo" (iThera Medical, Munich). Measurement of wavelengths from 680-950 nm. Detection of "regions of interest" (ROI) by ultrasound; evaluation of the values in the ROI for the spectra of water, fat, hemoglobin, oxygenated hemoglobin and HbT (=oxygenated and deoxygenated hemoglobin).

Results Values for 28 scans were included in the analysis (5 reactive lymph nodes, 18 squamous cell carcinoma metastases, 3 metastases papill. Thyroid carcinoma, 2 adenocarcinoma metastases). Comparison between reactive and metastatic lymph nodes shows significant differences for water content and HbT, no clear differences are seen in the other spectra.

Conclusion Ultrasound/MSOT hybrid scans represent a non-invasive examination method with which tissue can be additionally characterized qualitatively. Single MSOT spectra show significant differences between reactive and metastatic lymph nodes. MSOT could thus improve the possibilities of clinical lymph node staging and thus the planning of tumor treatments.

Publication History

Article published online:
24 May 2022