Contrast-Enhanced EIT Robustly Tracks Regional Lung Perfusion Compared to Non-Enhanced EIT and Pulmonary CT.

Abstract

Regional perfusion monitoring, often performed by pulmonary perfusion computed tomography, is vital in intensive care units. Electrical impedance tomography, repeatable and of non-invasive nature, could provide an attractive alternative. This study compares non-enhanced and contrast-enhanced electrical impedance tomography to computed tomography under induced central to peripheral lung perfusion impairments and cardiac output modulation in 11 animals. A new algorithmic framework using multi-compartment modeling and tracer kinetics was developed to improve perfusion estimation. A multi-resolution mixed models analysis shows electrical impedance tomography agrees poorly with computed tomography in static monitoring, with limits of agreement exceeding relative errors of 100%. For trend tracking,contrast-enhancement with 5.85% NaCl yielded concordance rates above 80%, and over 90% for peripheral impairments, emerging as a robust tracker of coarse to fine perfusion changes. Non-enhanced electrical impedance tomography peaked around 60% under central impairment and cardiac modulation, proving to be less reliable.