Multispectral Tissue Analysis

Pathological structures, e.g. tumors, can develop between or in the direct proximity to important structures, for example nerves. During surgery, it is hard to differentiate the various tissue types. Currently, this continuous differentiation is based on the surgeon’s knowledge only. A visualization of important tissue structures would allow the surgeon to perform operations faster and with less risk of patient damage. However, automatic methods based on optical in vivo properties of human tissue do not yet exist, as these properties have not been sufficiently examined. To overcome this, we develop and investigate several hyperspectral camera setups to monitor the different optical behavior of tissue types in vivo, as preoperative screening and tissue localization cannot be used to achieve a robust differentiation during surgery.

The first focus in multispectral tissue analysis is on ear, nose throat (ENT) surgery. In a first step, relevant tissue types has been extracted during surgical standard procedures and examined in a spectrophotometer to obtain the optical tissue properties of fresh tissue samples. Additionally, the same tissue types are analyzed with different optical camera-illumination setups.

Setup

We will investigate three different setups for the tissue analysis:

  • Hyperspectral snapshot samera and scene illumination with spectrally-broadband, visible-wavelength light (white light),
  • Monochromatic camera and scene illumination with different narrowband light sources,
  • RGB camera and scene illumination with different broader narrowband light sources.

Building an HSI-based computer-aided tissue analysis system requires accurate ground truth and validation of optical soft tissue properties as these show large variability. Therefore, the setups are calibrated and validated using the same database and calibration set. For validation, a color chart with 18 well-defined color spectra in the visual range is analyzed. Thus, the results acquired with all settings become transferable and comparable to each other as well as between different interventions.

Visualization

Further, we develop techniquesways to appropriatley visualize the extracted multispectral tissue information in a microscope or endoscope, e.g. by enhancing the reconstructed data in the relevant spectral range (e.g. 460 nm to 480 nm for nerve, see image).

Publications

E. L. Wisotzky, B. Kossack, F. C. Uecker, P. Arens, A. Hilsmann, P. Eisert
Validation of two techniques for intraoperative hyperspectral human tissue determination,
Journal of Medical Imaging, 7(6):065001, 2020. [pdf]

E. L. Wisotzky, Jean-Claude Rosenthal, Ulla Wege, Anna Hilsmann, Peter Eisert, Florian Uecker
Surgical Guidance for Removal of Cholesteatoma Using a Multispectral 3D-Endoscope,
Sensors, ISSN: 1424-8220, vol. 20, no. 18, September 2020, doi: 10.3390/s20185334

E. L. Wisotzky, P. Arens, S. Dommerich, A. Hilsmann, P. Eisert, F. C. Uecker,
Determination of optical properties of cholesteatoma in the spectral range of 250 to 800 nm, Biomedical Optics Express, 11(3), 2020. [pdf]

Eric Wisotzky, Jean-Claude Rosenthal, Florian Uecker, Anna Hilsmann, Peter Eisert,
A Multispectral 3D-Endoscope for Cholesteatoma Removal,
Current Directions in Biomedical Engineering, 6(3):20203065, 2020. [pdf]

E. L. Wisotzky, F. C. Uecker, S. Dommerich, A. Hilsmann, P. Eisert, P. Arens,
Determination of optical properties of human tissues obtained from parotidectomy in the spectral range of 250 to 800 nm, Journal of Biomedical Optics, 24(12):125001, 2019.

E. L. Wisotzky, B. Kossack, F. C. Uecker, P. Arens, S. Dommerich, A. Hilsmann, P. Eisert,
Validation of two techniques for intraoperative hyperspectral human tissue determination, Proceedings of SPIE, 10951:109511Z, 2019.

E. L. Wisotzky, F. C. Uecker, P. Arens, S. Dommerich, A. Hilsmann, and P. Eisert,
Intraoperative hyperspectral determination of human tissue properties, Journal of Biomedical Optics, 23(9):091409, 2018.

E. Wisotzky,
HSI in der diagnostischen und therapeutischen Medizin,
In M. Sackewitz (Hrsg.), Leitfaden zur Hyperspektralen Bildgebung, Vision Leitfaden 19, S. 80-83, Stuttgart, Fraunhofer Verlag, 2019. ISBN 978-3-8396-1502-7 [pdf]