# Hyperspectral imaging as an objective diagnostic tool for secondary lymphedema in breast cancer patients

## TL;DR

This study explores hyperspectral imaging as a noninvasive and objective tool for diagnosing and monitoring secondary lymphedema in breast cancer patients.

## Contribution

The study demonstrates that hyperspectral imaging outperforms conventional methods in detecting tissue changes associated with lymphedema.

## Key findings

- Hyperspectral imaging shows strong correlations with lymphedema stage through lipid-to-water ratio and tissue water index.
- Conventional methods like ultrasound and limb circumference measurements correlate moderately with disease stage.
- Hyperspectral imaging offers a reproducible, noninvasive alternative for assessing secondary lymphedema.

## Abstract

Secondary lymphedema is a common complication after breast cancer treatment. Traditional diagnostic techniques often lack objectivity, are prone to operator bias, and show limited reproducibility. There is a need for diagnostic methods that are reliable, noninvasive, and suitable for monitoring disease progression. This study (German Clinical Trials Register, DRKS-ID: DRKS00027366) aimed to evaluate hyperspectral imaging as a tool for detecting and classifying secondary lymphedema.

We conducted a prospective multicenter study including 58 women with unilateral secondary lymphedema. Lymphedema severity was categorized according to the International Society of Lymphology. Each participant underwent conventional assessments, including limb circumference measurements, two-point discrimination tests, joint mobility evaluation, and ultrasound imaging of skin and subcutaneous tissue, plus gave patient-reported outcomes. Hyperspectral images were collected using the TIVITA Tissue system, which captures light reflectance from 500 to 1000 nanometers. From these data, the lipid-to-water ratio and the TIVITA tissue water index were calculated to evaluate tissue changes related to lymphedema.

Here, we show that conventional methods correlate moderately with lymphedema stage, with ultrasound measurements of skin and subcutaneous thickness showing the strongest associations. Hyperspectral imaging shows strong correlations, with interlimb differences in lipid-to-water ratio and tissue water index outperforming conventional methods. These measurements highlight clear fluid accumulation in the affected limbs.

Hyperspectral imaging provides reproducible, objective, and noninvasive assessment of secondary lymphedema. These findings support its potential as a diagnostic and monitoring tool to improve staging and treatment evaluation.

Secondary lymphedema is swelling of a limb and is a frequent side effect of breast cancer treatment. Current diagnostic methods can be subjective and inconsistent. We assessed whether hyperspectral imaging, which measures light absorption in the skin to estimate tissue water and fat levels, could be a more reliable alternative. Fifty-eight women with one arm affected by lymphedema were examined using standard tests, including measuring the arm circumference, skin sensibility, joint mobility, ultrasound imaging, and patient-reported outcomes, as well as hyperspectral imaging. Hyperspectral imaging showed stronger correlations with disease stage than conventional methods. Our results suggest hyperspectral imaging may offer an objective, noninvasive, and more reliable way to diagnose and monitor secondary lymphedema.

The study was carried out at the Department of Women’s Health in Tübingen, at the Department of Hand, Plastic, Reconstructive and Burn Surgery, BG Unfallklinik Tübingen and in the Clinic for Plastic, Reconstructive and Breast Surgery at the Elblandklinikum Radebeul.

Weiss et al. evaluate hyperspectral imaging as an objective and noninvasive method for detecting secondary lymphedema after breast cancer treatment. Results show that hyperspectral imaging provides stronger correlations with disease stage than conventional methods.