In Vivo Bioimpedance Spectroscopy Characterization of Healthy, Hemorrhagic and Ischemic Rabbit Brain within 10 Hz–1 MHz

Abstract

Acute stroke is a serious cerebrovascular disease and has been the second leading cause of death worldwide. Conventional diagnostic modalities for stroke, such as CT and MRI, may not be available in emergency settings. Hence, it is imperative to develop a portable tool to diagnose stroke in a timely manner. Since there are differences in impedance spectra between normal, hemorrhagic and ischemic brain tissues, multi-frequency electrical impedance tomography (MFEIT) shows great promise in detecting stroke. Measuring the impedance spectra of healthy, hemorrhagic and ischemic brain in vivo is crucial to the success of MFEIT. To our knowledge, no research has established hemorrhagic and ischemic brain models in the same animal and comprehensively measured the in vivo impedance spectra of healthy, hemorrhagic and ischemic brain within 10 Hz–1 MHz. In this study, the intracerebral hemorrhage and ischemic models were established in rabbits, and then the impedance spectra of healthy, hemorrhagic and ischemic brain were measured in vivo and compared. The results demonstrated that the impedance spectra differed significantly between healthy and stroke-affected brain (i.e., hemorrhagic or ischemic brain). Moreover, the rate of change in brain impedance following hemorrhagic and ischemic stroke with regard to frequency was distinct. These findings further validate the feasibility of using MFEIT to detect stroke and differentiate stroke types, and provide data supporting for future research.

Anomaly Detection Using Electric Impedance Tomography Based on Real and Imaginary Images

“…Each material or network has an identical image impedance, resistance, and reactance image for each tissue. These three images have improved the accuracy of the EIT system in detecting abnormalities when compared to just one image [2][3][4][5][6][7][8][9][10][11]16]. The results obtained have been compared with data from other researchers' experiments [3], the results of these comparisons show a corresponding trend.…”

“…The weakness of the impedance image generated from the MF-EIT system [8,13] is its inability to distinguish objects that have the same impedance but are different tissues. Some tissues that have the similar impedance include liver and lungs with the impedance value of 1.622 Ω and 1.624 Ω, heart and deflated lung with the impedance value of 1.001 Ω and 1.077 Ω at the frequency of 10 khz.…”

Rabbit models of ischemic stroke in biomedical research

“…Наиболее распространенными способами индукции ишемии головного мозга у кроликов, не требующими проведения краниотомии, являются эмболизация средней мозговой артерии (СМА) [15][16][17][18], эндоваскулярная окклюзия [19][20][21] и фотохимически индуцированный тромбоз [22]. К моделям ИИ, требующим проведения краниотомии, относится прямая хирургическая окклюзия мозговых артерий, выполняемая путем клипирования [23] или наложения лигатур [24].…”

“…После того как глаза у животного окрашивались в соответствующий розовый цвет, на предварительно подготовленный участок черепа подавали в течение 30 минут зеленый свет с длиной волны 540 нм и интенсивностью 600 мВт/см 2 . Гистоморфологический анализ очага ишемии продемонстрировал набухание и вакуолизацию цитоплазмы, а также кариолизис и кариопикноз в нейронах и клетках глии [22].…”

Reconfigurable, Multi-channel and Modular Bioimpedance Spectroscopy System on Field Programmable Gate Arrays

“…By definition, bioimpedance can be described as the ability of biological tissues to restrict electrical current [1][2][3]. At cellular levels, studying impedance properties of cells allow detection of various substances such as chemical toxins, bacteria, viruses, due to the presence of the many types of receptors on cell membranes [2][3][4].…”