Determination of sensitive frequency margin for aggregated protein concentration quantification by fd-electrical impedance tomography. (December 2021)

• Record Type: Journal Article
• Authors: Sifuna, Martin W.; Baidillah, Marlin R.; Kawashima, Daisuke; Darma, Panji N.; Odari, Eddy O.; Takei, Masahiro
• Is Part Of: Measurement. Volume 186(2021)
• Publication Date: 2021-12
• Subjects: Sensitive frequency margin -- Interstitial protein aggregation -- Concentration quantification -- Fd-electrical impedance tomography; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2021.110135
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: Interstitium protein concentrations are monitored invasively and radiatively. EIT is noninvasive and nonradiative but requires pre-determined σ reference data. Fd -EIT is reference-independent and uses σ data measured between a frequency pair. The sensitive frequency margin (SFM) for interstitium protein is however unknown. This study aimed to determine the SFM using interstitium mimicking phantoms. Abstract: A sensitive frequency f margin SFM has been determined for quantification of aggregated interstitial protein concentrations Фprot by frequency difference electrical impedance tomography fd- EIT. Impedances of increasing Фprot of albumin-globulin mixtures in phantoms were measured and changes in protein's adjacent f point conductivity Δ σadj and loss factor Δ ε''adj plotted against f to determine a Фprot SFM fsen where σadj and ε''adj change significantly with Фprot . Results show that the Δ σadj and Δ ε''adj dropped rapidly with increase in f up to f = 10 kHz then gradually to f = 100 kHz. The σ and ε" were only sensitive to Фprot as f increased from 1 to 10 kHz. For fd -EIT, optimum reference frequency fref was set at 100 kHz. At fsen = 1 kHz against fref, fd -EIT reconstructed σ due to 30% increase in Фprot with area ratio error ARE = 4.1% and a position error PE = 0.1 [-].