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. 2022 Jan 28:2022:9522737.
doi: 10.1155/2022/9522737. eCollection 2022.

Microwave-Based Colonoscopy: Preclinical Evaluation in an Ex Vivo Human Colon Model

Glòria Fernández-Esparrach  1   2 , Alejandra Garrido  2 , Roberto Sont  2 , Walid Dghoughi  2 , Sergi Marcoval  2 , Miriam Cuatrecasas  3 , Sandra López-Prades  3 , F Borja de Lacy  4 , María Pellisé  1 , Ignasi Belda  2 , Marta Guardiola  2
Affiliations

Microwave-Based Colonoscopy: Preclinical Evaluation in an Ex Vivo Human Colon Model

Glòria Fernández-Esparrach et al. Gastroenterol Res Pract. .

Abstract

Introduction: Microwave imaging can obtain 360° anatomical and functional images of the colon representing the existing contrast in dielectric properties between different tissues. Microwaves are safe (nonionizing) and have the potential of reducing the visualization problems of conventional colonoscopy. This study assessed the efficacy of a microwave-based colonoscopy device to detect neoplastic lesions in an ex vivo human colon model.

Methods: Fresh surgically excised colorectal specimens containing cancer or polyps were fixed to a 3D positioning system, and the accessory device was introduced horizontally inside the ex vivo colon lumen and moved along it simulating a real colonoscopy exploration. Measurements of the colon were taken every 4 mm with the microwave-based colonoscopy device and processed with a microwave imaging algorithm.

Results: 14 ex vivo human colorectal specimens with carcinomas (n = 11) or adenomas with high grade dysplasia (n = 3) were examined with a microwave-based device. Using a detection threshold of 2.79 for the dielectric property contrast, all lesions were detected without false positives or false negatives.

Conclusions: This study demonstrates the use of a microwave-based device to be used as an accessory of a standard colonoscope to detect neoplastic lesions in surgically excised colorectal specimens.

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Conflict of interest statement

Glòria Fernández-Esparrach, Miriam Cuatrecasas, Maria Pellisé, Ignasi Belda, and Marta Guardiola are shareholders of MiWendo Solutions. Alejandra Garrido, Roberto Sont, Walid Dghoughi, Sergi Marcoval, Sandra López-Prades, and F. Borja de Lacy do not have any conflict of interest.

Figures

Figure 1
Figure 1
The imaging system consists of a cylindrical ring-shaped acquisition device attached to the tip of a colonoscope connected via cables to the external unit. The external unit consists of a microwave transceiver, a microcontroller, and a laptop.
Figure 2
Figure 2
Measurement setup. The colon is wrapped around a polystyrene tube, and the acquisition device is attached to the tip of a plastic bar and connected to the microwave transceiver, the microcontroller, and the laptop.
Figure 3
Figure 3
Reconstructed maximum dielectric property contrast of each patient and frame obtained with microwave-based colonoscopy for healthy mucosa areas and for lesions. The detection threshold fixed to 2.79 is represented as a horizontal red line. All values above the line are classified as lesion and below as healthy mucosa.
Figure 4
Figure 4
Image frames obtained with microwave-based colonoscopy. The dark blue circle in the middle of the plot indicates the position of the acquisition device, and the red dots the position of each antenna. (a) The highest intensity yellow spot indicates the presence of the polyp. (b) The colors are uniform showing that there are no lesions in the mucosa.
Figure 5
Figure 5
Correlation with the evolution of the maximum amplitude of each successive frame obtained with microwave-based colonoscopy (bottom) and the location of the lesion indicated by the arrows (top). Lower amplitudes around 0.2 are typical of healthy mucosa areas, while neoplastic lesions show high amplitudes close to 1.
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References

    1. Müller A. D., Sonnenberg A. Prevention of colorectal cancer by flexible endoscopy and polypectomy. A case-control study of 32,702 veterans. Annals of Internal Medicine . 1995;123:904–910. doi: 10.7326/0003-4819-123-12-199512150-00002. - DOI - PubMed
    1. Winawer S. J., Zauber A. G., Ho M. N., et al. Prevention of colorectal cancer by colonoscopic polypectomy. The New England Journal of Medicine . 1993;329:1977–1981. doi: 10.1056/NEJM199312303292701. - DOI - PubMed
    1. van Rijn J. C., Reitsma J. B., Stoker J., Bossuyt P. M., van Deventer S. J., Dekker E. Polyp miss rate determined by tandem colonoscopy: a systematic review. The American Journal of Gastroenterology . 2006;101(2):343–350. doi: 10.1111/j.1572-0241.2006.00390.x. - DOI - PubMed
    1. Samadder N. J., Curtin K., Tuohy T. M., et al. Characteristics of missed or interval colorectal cancer and patient survival: a population-based study. Gastroenterology . 2014;146(4):950–960. doi: 10.1053/j.gastro.2014.01.013. - DOI - PubMed
    1. Lee T., Rees C., Blanks R., et al. Colonoscopic factors associated with adenoma detection in a national colorectal cancer screening program. Endoscopy . 2014;46:203–211. doi: 10.1055/s-0033-1358831. - DOI - PubMed