Electrical Impedance Tomography (EIT): A Review

Abstract

Electrical Impedance Tomography (EIT) is a non-invasive imaging technique that estimates the internal electrical conductivity distribution of a subject using surface electrode measurements. This paper provides a comprehensive review of EIT, detailing its fundamental operating principles, system construction, and diverse applications, particularly within the medical field. Unlike conventional imaging modalities such as CT or MRI, EIT offers a portable, low-cost, and radiation-free alternative suitable for continuous, real-time bedside monitoring. The study outlines the essential hardware components, including active and passive electrode arrays, and discusses the complex non-linear inverse algorithms required for image reconstruction. Key medical applications are highlighted, including the monitoring of pulmonary ventilation and lung injury, early detection of breast cancer, analysis of intracranial bleeding and brain function, and fetal monitoring. The paper also explores recent technological advancements, such as the use of nanoparticle sensitizers to enhance tissue contrast and the development of micro-electrode arrays for precise measurements. Despite challenges regarding low spatial resolution and sensitivity to noise, EIT remains a promising tool for physiological monitoring. The review concludes that ongoing improvements in hardware design and reconstruction algorithms are expanding EIT’s clinical utility, offering a safer and more accessible solution for long-term patient diagnosis and care.