Electrical impedance tomography for non-invasive identification of fatty liver infiltrate in overweight individuals
Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes of cardiometabolic diseases in overweight individuals. While liver biopsy is the current gold standard to diagnose NAFLD and magnetic resonance imaging (MRI) is a non-invasive alternative still under clinical trials, the former is invasive and the latter costly. We demonstrate electrical impedance tomography (EIT) as a portable method for detecting fatty infiltrate. We enrolled 19 overweight subjects to undergo liver MRI scans, followed by EIT measurements. The MRI images provided the a priori knowledge of the liver boundary conditions for EIT reconstruction, and the multi-echo MRI data quantified liver proton-density fat fraction (PDFF%) to validate fat infiltrate. Using the EIT electrode belts, we circumferentially injected pairwise current to the upper abdomen, followed by acquiring the resulting surface-voltage to reconstruct the liver conductivity. Pearson's correlation analyses compared EIT conductivity or MRI PDFF with body mass index, age, waist circumference, height, and weight variables. We reveal that the correlation between liver EIT conductivity or MRI PDFF with demographics is statistically insignificant, whereas liver EIT conductivity is inversely correlated with MRI PDFF (R = −0.69, p = 0.003, n = 16). As a pilot study, EIT conductivity provides a portable method for operator-independent and cost-effective detection of hepatic steatosis.
Additional Information© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Received 01 June 2021; Accepted 16 September 2021; Published 06 October 2021. The present work was funded by the National Institutes of Health R01HL083015 (TKH), R01HL111437 (TKH), R01HL129727 (TKH), R01HL118650 (TKH), VA MERIT AWARD I01 BX004356 (TKH), and American Heart Association 19CDA34769186 (AK). Data availability: The authors declare that the main data supporting the findings of this study are available within the article and its Supporting Information files. Extra data are available from the corresponding author on a reasonable request. These authors contributed equally: Chih-Chiang Chang and Zi-Yu Huang. Author Contributions: C.C, Z.H, Y.L, and Y.C.T conducted the EIT reconstructions and analyses. Z.L. provided the clinical support for patient recruitment, liver MRI and PDFF. S.S, H.W, C.C, and S.D performed the MRI imaging and PDFF analyses. C.C, S.S, Z.H, Y.L, Q.C, and A.K, performed the EIT measurement following liver MRI scans. S.C, and Z.L prepared the IRB approval to recruit and coordinate the subjects for the MRI scans. T.K.H led the conception of liver EIT, the overall direction, and manuscript preparation with H.W, P.P, J.J, W.G, J. S, and A.B. All authors reviewed the manuscript. The authors declare no competing interests.
Published - s41598-021-99132-z.pdf
Submitted - 2020.12.21.423854v1.full.pdf
Supplemental Material - 41598_2021_99132_MOESM1_ESM.pdf