Electric impedance spectroscopy of human atherosclerotic lesions

Two-Point Stretchable Electrode Array for Endoluminal Electrochemical Impedance Spectroscopy Measurements of Lipid-Laden Atherosclerotic Plaques

“…We characterize the stretchable sensors in terms of distinct changes in impedance and phase spectra in response to balloon inflation pressure. Our 2-point approach represents an advancement to the previously proposed linear 4-point electrode arrays 28, 29, 30 , which preclude detection of small and non-homogeneous lesions. Thus, we demonstrate a simplified 2-point electrode configuration to advance the electrochemical impedance measurements for intraplaque lipid-laden lesions.…”

“…However, fat tissue is anhydrous and thus, a poor conductor. The high lipid content, including negatively charged active lipids such as oxidized low density lipoprotein (oxLDL) 27 and foam cells present in the plaque change the endoluminal electrochemical properties that can be measured by EIS 17,28,29,30 …”

Stretchable electrochemical impedance sensors for intravascular detection of lipid-rich lesions in New Zealand White rabbits

“…While the high-frequency IVUS (20–60 MHz) will enable us to resolve spatial resolution from 400 μm to 30 μm, the concentric bipolar microelectrode sensor will detect distinct endoluminal impedance spectrum in the presence of high-fat versus normal diets (Streitner et al, 2009; Suselbeck et al, 2005). This integrated IUVS-EIS strategy will likely enhance the possibility of co-registration of ultrasound with the EIS measurements, and will detect an increase in EIS magnitude in non-obstructive lesions that occupy less than 20% of the luminal diameter, but harbor oxLDL and foam cells (Fig.…”

“…We further demonstrated that spatial (∂τ/∂x) and temporal (∂τ/∂t) variations in shear stress regulate post-translational modifications of LDL; namely, oxidation and nitration, as well as recruitment of monocytes (Ai et al, 2008; Hsiai et al, 2007; Hwang, Michael, et al, 2003; Hwang, Saha, et al, 2003). These findings led to our novel observation that oxLDL and macrophages changed the electrochemical properties in the vessel wall that can be measured by electrochemical impedance spectroscopy (EIS) (Konings, Mali, & Viergever, 1997; Streitner et al, 2009; Suselbeck et al, 2005). …”

“…A group of German investigators recently reported the application of a linear 4-point microelectrode that was affixed to a 2 centimeters long balloon catheter in NZW rabbits (Konings et al, 1997; Streitner et al, 2009; Suselbeck et al, 2005). Unlike the lengthy 4-point microelectrodes, the advantage of our bipolar microelectrode sensor lies in its concentric configuration (300 μm in diameter) that is conformal to the non-homogeneous tissue composition, non-planar endoluminal surface, and non-uniform electric current distribution of the atherosclerosis.…”