The evaluation of blood compatibility of biomaterials is crucial for ensuring the clinical safety of implantable medical devices. To address the limitations of traditional testing methods in real-time monitoring and electrical property analysis, this study developed a portable electrical impedance tomography (EIT) system. The system uses a 16-electrode design, operates within a frequency range of 1 to 500 kHz, achieves a signal to noise ratio (SNR) of 69.54 dB at 50 kHz, and has a data collection speed of 20 frames per second. Experimental results show that the EIT system developed in this study is highly consistent with a microplate reader ( R ²=0.97) in detecting the hemolytic behavior of industrial-grade titanium (TA3) and titanium alloy-titanium 6 aluminum 4 vanadium (TC4) in anticoagulated bovine blood. Additionally, with the support of a multimodal image fusion Gauss-Newton one-step iterative algorithm, the system can accurately locate and monitor in real-time the dynamic changes in blood permeation and coagulation caused by TC4 in vivo. In conclusion, the EIT system developed in this study provides a new and effective method for evaluating the blood compatibility of biomaterials.
Electric Impedance ; Animals ; Tomography/instrumentation* ; Biocompatible Materials ; Materials Testing/instrumentation* ; Cattle ; Titanium ; Alloys ; Prostheses and Implants

Real-time acquisition of pulmonary ventilation and perfusion information through thoracic electrical impedance tomography (EIT) holds significant clinical value. This study proposes a novel method based on the rime (RIME) algorithm-optimized variational mode decomposition (VMD) to separate lung ventilation and perfusion signals directly from raw voltage data prior to EIT image reconstruction, enabling independent imaging of both parameters. To validate this approach, EIT data were collected from 16 healthy volunteers under normal breathing and inspiratory breath-holding conditions. The RIME algorithm was employed to optimize VMD parameters by minimizing envelope entropy as the fitness function. The optimized VMD was then applied to separate raw data across all measurement channels in EIT, with spectral analysis identifying relevant components to reconstruct ventilation and perfusion signals. Results demonstrated that the structural similarity index (SSIM) between perfusion images derived from normal breathing and breath-holding states averaged approximately 84% across all 16 subjects, significantly outperforming traditional frequency-domain filtering methods in perfusion imaging accuracy. This method offers a promising technical advancement for real-time monitoring of pulmonary ventilation and perfusion, holding significant value for advancing the clinical application of EIT in the diagnosis and treatment of respiratory diseases.
Humans ; Electric Impedance ; Algorithms ; Tomography/methods* ; Pulmonary Ventilation/physiology* ; Lung/diagnostic imaging* ; Image Processing, Computer-Assisted/methods* ; Adult

Electrical impedance tomography (EIT) is a new non-invasive functional imaging technology, which has the advantages of non-invasion, non-radiation, low cost, fast response, portability and visualization. In recent years, more and more studies have shown that EIT has great potential in the detection of lung diseases and has been applied to early diagnosis and treatment of some diseases. This paper introduced the basic principle of EIT, discussed the research and clinical application of EIT in the detection of acute respiratory distress syndrome, chronic obstructive pulmonary disease, pneumothorax and pulmonary embolism, and focused on the summary and introduction of indicators and functional images of EIT related to the detection of lung diseases. This review will help medical workers understand and use EIT, and promote the further development of EIT in lung diseases as well as other fields.
Humans ; Electric Impedance ; Tomography/methods* ; Lung Diseases/diagnosis* ; Pulmonary Disease, Chronic Obstructive/diagnosis* ; Pulmonary Embolism/diagnosis* ; Respiratory Distress Syndrome/diagnosis*

To address the challenges of capturing micro-strains in detecting esophageal motility disorders and the limitations of existing high-resolution manometry and functional intraluminal imaging probes in directly measuring esophageal tissue electrical impedance, this study proposes a novel flexible balloon sensor structure that integrates a piezoelectric film assembly with a distributed impedance electrode array. Using the electrical analysis module in the finite element analysis (FEA) software, simulations of the forward problem for esophageal impedance detection were conducted to optimize the excitation source parameters, and a physical prototype was fabricated. Under a relative excitation mode with a voltage sensitivity of 2.059%, the voltage output characteristics of the impedance electrode array were analyzed during linear changes in the balloon filling volume. Based on the performance variation of the piezoelectric film assembly, 80% was selected as the optimal filling volume. Force-electric coupling tests were conducted on the balloon sensor using a pressure testing platform, revealing that both the piezoelectric film assembly inside the balloon and the impedance electrodes outside the balloon exhibited significant load differentiation characteristics as the force application point shifted. In summary, this balloon sensor facilitates the localization of force application while simultaneously analyzing esophageal tissue properties, offering a novel diagnostic approach and objective tool for esophageal disease detection.
Esophagus/physiology* ; Electric Impedance ; Humans ; Finite Element Analysis ; Manometry/methods* ; Electrodes ; Esophageal Motility Disorders/physiopathology* ; Equipment Design

OBJECTIVES: To assess the changes in body composition and nutritional risks faced by children with different stages of acute leukemia (AL). METHODS: Bioelectrical impedance analysis combined with anthropometric measurements was used to detect body composition. This prospective study was conducted from August 2023 to July 2024 at Shandong Provincial Hospital, examining the body composition and physical balance of children with various stages of AL and healthy children. RESULTS: The non-fat components of children with AL and healthy children both showed a linear increase with age. In the younger age group, there were no significant differences in body composition between children with AL and healthy children. However, in the older age group, the body composition of children undergoing chemotherapy for AL was significantly lower than that of healthy children (P<0.05), and muscle mass recovered first after the completion of AL chemotherapy. The proportion of children with increased trunk fat in AL children who completed chemotherapy was significantly lower than that in healthy children (P<0.05), while the incidence rate of severe left-right imbalance in body composition was significantly higher (P<0.05). Muscle distribution in children with AL primarily showed insufficient limb and overall muscle mass, whereas healthy children mainly exhibited insufficient upper limb muscle mass. CONCLUSIONS The body composition of children with AL varies at different treatment stages, indicating that nutritional status is affected by both the disease itself and the treatment. Early screening can provide a basis for reasonable nutritional intervention.
Humans ; Child ; Male ; Female ; Child, Preschool ; Body Composition ; Prospective Studies ; Adolescent ; Leukemia/metabolism* ; Infant ; Nutritional Status ; Acute Disease ; Electric Impedance

Electrical impedance tomography (EIT) is a technique that uses an array of electrodes to deliver safe stimulating currents and measures the boundary voltages between adjacent electrode pairs in the array in sequence. Subsequently, it reconstructs the impedance distribution in all or part of the tissue using reconstruction algorithms to achieve structural and functional imaging. Lung EIT technology features continuity, being radiation-free and non-invasive, and it can be used for real-time dynamic monitoring of the lungs in critically ill patients. This paper introduces the basic principles of lung EIT, analyzes the research progress and existing problems of the technology from the perspectives of hardware systems, imaging algorithms, and clinical applications (such as lung ventilation, lung perfusion, and lung function assessment), and discusses the development direction to provide ideas for expanding the clinical application of lung EIT.
Electric Impedance ; Humans ; Tomography/methods* ; Lung Diseases/therapy* ; Algorithms

The minimally invasive thermal ablation technology differs from traditional surgical operations, which requires auxiliary equipment to evaluate ablation results. However, the ultrasound and CT currently used in clinical practice have shortcomings such as artifacts and radiation. Therefore, this paper proposes a design for a minimally invasive thermal ablation evaluation system based on the principle of electrical impedance tomography technology to monitor the ablation range. At the same time, the innovative introduction of a programmable gain feedforward signal as the parameter signal of the multiplier demodulator in the electrical impedance tomography system design can effectively solve the problem of weak signals being submerged in noise and improve imaging accuracy. The system controls the amplitude of the excitation current signal and the acquisition / processing of boundary voltages via an STM32, uploads the collected data to an upper computer, and reconstructs the conductivity distribution using the Newton-Raphson algorithm to map the size of the ablation area. Experimental results show that the system can effectively reflect the size of the microwave ablation area. Under the same minimally invasive ablation parameters, the average imaging errors are 0.6 mm for the long diameter, 0.8 mm for the short diameter, and 1.75% for the axial ratio (long diameter / short diameter), demonstrating high consistency. This verifies the technical potential of electrical impedance tomography in minimally invasive thermal ablation.
Electric Impedance ; Tomography/instrumentation* ; Equipment Design

Electrical impedance tomography (EIT) represents an emerging medical functional imaging technology, which operates by applying safe-to-human excitation currents through surface-mounted electrodes, measuring boundary voltages between electrodes, and selecting appropriate image reconstruction algorithms to visualize resistivity in tomographic cross-sections. Compared to traditional medical imaging techniques, EIT offers non-invasive and radiation-free operation, high sensitivity to tissue resistivity changes, and superior temporal resolution, meeting the real-time requirements of clinical dynamic condition monitoring. This paper comprehensively reviews the research status of brain EIT technology, systematically summarizes its advantages and technical limitations in perioperative applications, and prospectively forecasts future development directions of perioperative brain EIT based on current research foundations and clinical application demands, with the aim of providing methodological references for further optimization and clinical promotion of this technology.
Electric Impedance ; Tomography/methods* ; Humans ; Brain/diagnostic imaging*

Cerebral hemorrhage is a serious cerebrovascular disease with high morbidity and high mortality, for which timely diagnosis and treatment are crucial. Electrical impedance tomography (EIT) is a functional imaging technique which is able to detect abnormal changes of electrical property of the brain tissue at the early stage of the disease. However, irregular multi-layer structure and different conductivity properties of each layer affect image reconstruction of the brain EIT, resulting in low reconstruction quality. To solve this problem, an image reconstruction method based on an improved densely-connected fully convolutional neural network is proposed in this paper. On the basis of constructing a three-layer cerebral model that approximates the real structure of the human head, the nonlinear mapping between the boundary voltage and the conductivity change is determined by network training, which avoids the error caused by the traditional sensitivity matrix method used for solving inverse problem. The proposed method is also evaluated under the conditions with or without noise, as well as with brain model change. The numerical simulation and phantom experimental results show that conductivity distribution of cerebral hemorrhage can be accurately reconstructed with the proposed method, providing a reliable basis for the diagnosis and treatment of cerebral hemorrhage. Also, it promotes the application of EIT in the diagnosis of brain diseases.
Humans ; Cerebral Hemorrhage/diagnostic imaging* ; Neural Networks, Computer ; Electric Impedance ; Image Processing, Computer-Assisted/methods* ; Tomography/methods* ; Brain/diagnostic imaging* ; Phantoms, Imaging ; Convolutional Neural Networks

Objective: To investigate the characteristics of the time-point distribution of the occurrence of laryngopharyngeal reflux (LPR) by 24-hour multichannel intraluminal impedance-pH monitoring (24 h MII-pH) and to provide guidance for the development of individualized anti-reflux strategies for LPR patients. Methods: We conducted a retrospective analysis of 24 h MII-pH data from 408 patients [339 males and 69 females, aged 23-84 (55.08±11.08) years] attending the Department of Otorhinolaryngology Head and Neck Surgery at the Sixth Medical Center of the PLA General Hospital from January 2013 to March 2020. The number of gas acid/weak-acid reflux, mixed gas-liquid acid/weak-acid reflux, liquid acid/weak-acid reflux and alkaline reflux events at different time points were recorded and statistically analyzed through SPSS 26.0 software. Results: A total of 408 patients were included. Based on the 24 h MII-pH, the total positive rate of LPR was 77.45% (316/408). The type of positive gaseous weak-acid reflux was significantly higher than the remaining types of LPR (χ²=297.12,P<0.001). Except the gaseous weak-acid reflux, the occurrence of the remaining types of LPR showed a tendency to increase after meals, especially after dinner. Liquid acid reflux events occurred mainly between after dinner and the following morning, and 47.11% (57/121) of them occurred within 3 h after dinner. There was a significant positive association between Reflux Symptom Index scores and gaseous weak-acid reflux(r=0.127,P<0.01), liquid acid reflux(r=0.205,P<0.01) and liquid weak-acid reflux(r=0.103,P<0.05)events. Conclusions: With the exception of gaseous weak-acid reflux events, the occurrence of the remaining types of LPR events has a tendency to increase after meals, especially after dinner. Gaseous weak-acid reflux events accounts for the largest proportion of all types of LPR events, but the pathogenic mechanisms of gaseous weak-acid reflux are needed to further investigate.
Male ; Female ; Humans ; Laryngopharyngeal Reflux/diagnosis* ; Retrospective Studies ; Esophageal pH Monitoring ; Otolaryngology ; Software ; Electric Impedance