Poster R11 - Flexible On-Skin Electrical Impedance Tomography for Early and Remote Detection of Fatty Liver Disease

Introduction: Obesity is a rising pandemic and more than two third of Americans are overweight. Obesity-related non-alcoholic fatty liver disease (NAFLD) is a silent killer. If undetected, NAFLD progresses to liver cirrhosis and cancer. Electrical Impedance Tomography (EIT) is an emerging imaging modality for assessing tissue-specific electrical conductivity. Fatty infiltrate in the liver is characterized by its frequency-dependent electrical impedance (Z) in response to applied alternating current (AC). However, existing EIT systems are bulky and impractical for point-of-care or remote detection.

Materials and

Methods: In this study, we fabricated a flexible and portable EIT belt (pEIT) for hepatic fat fraction (HFF%) reconstruction. Our pEIT is designed to be compact, lightweight, and operator-independent, enabling seamless integration into clinical workflows. The AC currents with a programmable magnitude from 1–4 mA were injected to the upper abdomen at frequencies ranging from 50—250 kHz through selected channels. The resulting voltage responses were recorded by a separate pair of multiplexed electrodes. Based on the liver boundary conditions, we employed the acquired voltage data to calculate the ill-posed EIT inverse problem for liver conductivity (S∙m-1). We developed advanced signal processing algorithms and machine learning techniques to reconstruct the 2-D conductivity distribution. We further evaluated the performance of the pEIT device using tissue-mimicking phantoms and preclinical models of NAFLD, and we demonstrated the pEIT system to detect variations in HFF% with high sensitivity and specificity.

Results, Conclusions, and Discussions: In conclusion, our work presents a significant step towards an accessible and equitable sensor for early and non-invasive assessment of HFF%. While abdominal MRI is the reference standard for noninvasive modalities, our results show the pEIT device holds great promise for affordable and early detection of NAFLD for socioeconomically disadvantaged communities.

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