Identifying and Localizing of the In-depth Pulmonary Nodules Using Electrical Bio-Impedance

Comparison of three-dimensional reconstruction and CT-guided Hook-wire segmental resection for pulmonary nodules: a propensity score matching study

OBJECTIVE

To analyze and compare the clinical application value of three-dimensional reconstruction and computed tomography (CT)-guided Hook-wire localization for row lung segment resection of pulmonary nodules.

METHODS

Retrospective analysis of the clinical data of 204 patients suffering from pulmonary nodules admitted to the Department of Thoracic Surgery of Gansu Provincial People's Hospital from June 2016 to December 2022. According to the preoperative positioning method, the group was divided into a 3D reconstruction group (98 cases) and a Hook-wire group (106 cases), respectively. The two groups of patients were propensity score matching (PSM) to compare their perioperative outcomes.

RESULTS

All patients in both groups underwent successful surgeries without perioperative deaths. After PSM, 79 patients were successfully matched in each group. Two cases of pneumothorax, three cases of hemothorax, and four cases of decoupling occurred in the Hook-wire group; no complications of pneumothorax, hemothorax, and decoupling occurred in the 3D reconstruction group. Compared to the Hook-wire group, the 3D reconstruction group has shorter operative time (P = 0.001), less intraoperative bleeding (P < 0.001), less total postoperative chest drainage (P = 0.003), shorter postoperative tube placement time (P = 0.001), shorter postoperative hospital stay (P = 0.026), and postoperative complications (P = 0.035). There was no statistically significant difference between the two groups in terms of pathological type, TNM staging, and number of lymph node dissection.

CONCLUSION

Three-dimensional reconstruction and localization of pulmonary nodules enables safe and effective individualized thoracoscopic anatomical lung segment resection with a low complication rate, which has good clinical application value.

Bioimpedance sensor to detect water content in milk based on van Der Pauw method

Milk fraud poses serious problems for the dairy industry and consumers' health. The main aim of this study was to reveal the effect of water added to milk by measuring its electrical impedance spectrum. The required sensor was designed based on the van der Pauw method to measure the electrical conductivity of milk at the frequency band of 10 Hz to 5 MHz. The bioimpedance spectrum of the milk of five different cows showed that the electrical impedance spectrum has a high potential for detecting water added to the milk (P < 0.01). The area under the Nyquist curve was introduced as a suitable index to detect water‐added milk. In addition, the characteristic frequency of the bioimpedance spectrum was used as an important index to differentiate water‐added milk from waterless milk. An electrical model was introduced to interpret the amount of water added to the milk using the characteristic frequency. Results showed that it is possible to detect raw milk from boiled milk by measuring its electrical impedance.

The Development of a Four-Electrode Bio-Impedance Sensor for Identification and Localization of Deep Pulmonary Nodules

Identifying and localizing of deep pulmonary nodules are among the main challenges that thoracic surgeons face during operations, particularly in thoracoscopic procedures. To facilitate this, we have tried to introduce a non-invasive and safe method by measuring the lung electrical bio-impedance spectrum with a four-electrode array sensor. To study the feasibility of this method, since any change in the depth or diameter of the nodule in the lung tissue is not practical, we used the finite element modeling of the lung tissue and pulmonary nodule to allow changes in the depth and diameter of the nodule, as well as the distance in between the injection electrodes. Accordingly, a bio-impedance sensor was designed and fabricated. By measuring the electrical impedance spectrum of pulmonary tissues in four different specimens with a frequency band of 50 kHz to 5 MHz, 4 pulmonary nodules at four different depths were identified. The obtained bio-impedance spectrum from the lung surface showed that the magnitude and phase of electrical bio-impedance of the tumoral tissue at each frequency is smaller than that of the healthy tissue. In addition, the frequency characteristic varies in the Nyquist curves for tumoral and healthy lung tissues.

Identification of Pulmonary Nodules by Sweeping the Surface of the Lung with an Electrical Bioimpedance Probe: A Feasibility Study

Purpose: Identifying and localizing the invisible and nonpalpable pulmonary nodules are among the main challenges surgeons face during open and thoracoscopic surgeries. This in vitro study explores the feasibility of utilizing a simple and safe electrical bioimpedance probe in locating the pulmonary nodules by sweeping the surface of the lung tissue. Methods: A probe was designed with four spherical electrodes that were used for recording the bioimpedance spectrum of the lung tissue in a frequency range of 50 kHz to 5 MHz. In each of the 10 resected surgical specimens, the bioimpedance of normal lung tissue as well as the tumoral lung tissue were recorded and compared with each other. Results: By drawing the Nyquist curves, it was determined that the amplitude of the electrical impedance measured by moving the probe from the healthy point to the region of the pulmonary nodule decreases and the frequency characteristics of the bioimpedance spectrum increases. Conclusion: This method could be potentially beneficial in the localization of invisible and even nonpalpable in-depth pulmonary nodules in thoracic surgeries.