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ORIGINAL RESEARCH article

Front. Physiol.
Sec. Environmental, Aviation and Space Physiology
Volume 15 - 2024 | doi: 10.3389/fphys.2024.1460131
This article is part of the Research Topic Space Physiology and Medicine: Reports and Unique Data Obtained on Small Sample Sizes View all 9 articles

Liver tissue changes during and post 6-month spaceflight as measured by ultrasound radio frequency signal processing

Provisionally accepted
Philippe L. ARBEILLE Philippe L. ARBEILLE *Kathryn ZUJ Kathryn ZUJ Laurent GUILLON Laurent GUILLON
  • Unité de Médecine et Physiologie Spatiales (UMPS-CERCOM), Centre Hospitalier Universitaire Trousseau de Tours, Tours, France

The final, formatted version of the article will be published soon.

    Background: Analysis of ultrasound radio frequency (RF) allows for the determination of the index of reflectivity (IR) which is a new measure that is dependent on tissue properties. Previous work has shown differences in the IR of the carotid artery wall with long duration spaceflight (Arbeille et al 2021); therefore, it was hypothesized that liver tissue would also show differences in this measure with spaceflight.Methods: The RF signal of a liver tissue sample was displayed and processed along 6 different lines covering a surface of approximately 2 x 2cm of the sample. The IR was calculated as the energy backscattered by the liver sample, divided by the total energy returned to the ultrasound probe.Results: Seven astronauts were investigated preflight, inflight on day 150, and postflight 4 days and 6 months after rerunning to Earth. Compared to preflight (65% ± 18%), the liver tissue sample IR was significantly lower on flight day 150 (49% ± 15%; p=0.022) and four days postflight (46% ± 19%; p=0.023). At 6 months postflight, the IR had returned to preflight values (59% ± 13%; p=0.941).The significant decrease of the coefficient of reflectivity means that inflight and four days postflight, the liver tissue reflected less ultrasound waves than preflight. This suggests a change in tissue properties through either the addition of particles that do not reflect ultrasound waves, or structural or cellular changes that alter the reflectivity of the tissue.

    Keywords: Liver, Radio frequency signal, RF, echography, spaceflight

    Received: 05 Jul 2024; Accepted: 13 Aug 2024.

    Copyright: © 2024 ARBEILLE, ZUJ and GUILLON. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Philippe L. ARBEILLE, Unité de Médecine et Physiologie Spatiales (UMPS-CERCOM), Centre Hospitalier Universitaire Trousseau de Tours, Tours, France

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