Non-Invasive Imaging and Scoring of Peritoneal Metastases in Small Preclinical Animal Models Using Ultrasound: A Preliminary Trial

Roxan F.C.P.A. Helderman, Mauricio Tobón Restrepo, Hans M. Rodermond, Gregor G.W. van Bochove, Daan R. Löke, Nicolaas A.P. Franken, H. Petra Kok, Pieter J. Tanis, Johannes Crezee, Arlene L. Oei*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Background: The peritoneum is a common site for the formation of metastases originating from several gastrointestinal and gynecological malignancies. A representative preclinical model to thoroughly explore the pathophysiological mechanisms and to study new treatment strategies is important. A major challenge for such models is defining and quantifying the (total) tumor burden in the peritoneal cavity prior to treatment, since it is preferable to use non-invasive methods. We evaluated ultrasound as a simple and easy-to-handle imaging method for this purpose. Methods: Peritoneal metastases were established in six WAG/Rij rats through i.p. injections of the colon carcinoma cell line CC-531. Using ultrasound, the location, number and size of intraperitoneal tumor nodules were determined by two independent observers. Tumor outgrowth was followed using ultrasound until the peritoneal cancer index (PCI) was ≥8. Interobserver variability and ex vivo correlation were assessed. Results: Visible peritoneal tumor nodules were formed in six WAG/Rij rats within 2–4 weeks after cell injection. In most animals, tumor nodules reached a size of 4–6 mm within 3–4 weeks, with total PCI scores ranging from 10–20. The predicted PCI scores using ultrasound ranged from 11–19 and from 8–18, for observer 1 and 2, respectively, which was quite similar to the ex vivo scores. Conclusions: Ultrasound is a reliable non-invasive method to detect intraperitoneal tumor nodules and quantify tumor outgrowth in a rat model.

Original languageEnglish
Article number1610
Issue number7
Publication statusPublished - 6 Jul 2022

Bibliographical note

Funding Information:
Funding: This research was funded by the Dutch Cancer Society, UVA grant number 10595. The ultrasound system was funded by the Maurits and Anna de Kock stichting.

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© 2022 by the authors. Licensee MDPI, Basel, Switzerland.


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