Search

Changjuan Li,1,2 Jianwei Mi,1 Fulai Gao,1 Xinying Zhu,1 Miao Su,1 Xiaoli Xie,1 Dongqiang Zhao1 1Department of Gastroenterology, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei Province, People’s Republic of China; 2Department of Gastroenterology, The First Hospital of Handan City, Handan, 056002, Hebei Province, People’s Republic of ChinaCorrespondence: Dongqiang ZhaoDepartment of Gastroenterology, The Second Hospital of Hebei Medical University, No. 215, He ping West Road, Xinhua District, Shijiazhuang, Hebei Province, 050000, People’s Republic of ChinaTel +86 0311 66636179Email hbzdq1998@163.comPurpose: We aimed to compare the histological and/or cytological diagnostic outcomes of EUS-FNA using 19G and 22G needles for solid pancreatic lesions and to evaluate the feasibility and safety of 19G needle.Patients and Methods: Data from patients with solid pancreatic lesions, who underwent EUS-FNA, were retrospectively retrieved from a single tertiary center from June 2017 to January 2021. The sensitivity, specificity, and accuracy of diagnosis, sample adequacy, number and time of punctures, and adverse events, were compared between the 19G and 22G groups. Univariate and multivariate logistic regression analyses were used to identify optimal factors for a correct histological diagnosis.Results: A total of 186 patients (19G group, n = 90; 22G group, n = 96) were analyzed in the study. The higher sensitivity and accuracy were observed in 19G group than those in the 22G group both in histological evaluation (89.3% vs 76%, p = 0.031; 91.1% vs 79.2%, p = 0.023; respectively) and in the combined histological and cytological evaluations (93.3% vs 81.3%, p = 0.027; 94.4% vs 84.3%, p = 0.027, respectively). However, there were no significant differences in specificity, positive predictive value (PPV), and negative predictive value (NPV). The number of needle passes and the puncture time were significantly lower in the 19G group than that in the 22G group (1.66 ± 0.07 vs 2.25 ± 0.08, p < 0.001; 125.4 ± 4.93s vs 169.0 ± 5.6s p < 0.001; respectively). Only 2 cases were failed in the 19G group and no serious complications occurred. Univariate and multivariate logistic analyses suggested that CA199 levels and needle types are related to the accuracy of the EUS-FNA histological diagnosis.Conclusion: EUS-FNA using a 19G needle is effective and safe for solid pancreatic lesions. Compared with the 22G needle, EUS-FNA with a 19G needle can obtain a better histological diagnostic accuracy of solid pancreatic lesions, and with fewer needle passes and in a shorter time.Keywords: sensitivity, specificity, diagnostic accuracy, histology, cytology

The magneto-acoustic synchronous method has found wide application in accurate positioning of power cable fault due to its advantages of high accuracy and strong ability to reject interference. In the view of principle, the magneto-acoustic synchronous method needs to detect the discharge sound signal and electromagnetic signal emitted from the fault point, but the discharge sound signal is easy to be interfered by the ambient noise around and the magnetic sound synchronization. Therefore, it is challenging to quickly and accurately detect the fault location of cable especially in strong background noise environment. On the other hand, the spectral subtraction is a relatively traditional and effective method in many intelligent background noise reduction technologies, which is characterized by a relatively small computational cost and strong real-time performance. However, its application is limited because the algorithm displays poor performance in low Signal to Noise Ratio (SNR) environment. Aiming at the shortcoming of the spectral subtraction that de-noising effect is weak in low SNR environment, this paper proposes an improved spectral subtraction combining the magnetic sound synchronous principle and analyzing the properties of discharging sound. This method can accurately estimate noise in real time and optimize the performance of the basic spectral subtraction thus solving the problem that the magneto-acoustic synchronous method is unsatisfactory for positioning cable fault in the strong background noise environment.

In the case of malfunction in power cables, it is feasible to obtain the location information of fault point by using reflection phenomenon of traveling waves occurred during transmission due to the fact that the characteristic impedance of fault point changes. However, the energy attenuation and distortion of traveling waves in fault detection of long power cable become the key influence factors of extracting fault reflection signal, which ultimately affect the measurement accuracy. Therefore, by employing the successive optimized high-frequency pulse signal instead of the single pulse signal used in the traditional testing equipment for the long power cable fault-detection, this paper proposes a signal processing method based on digital non-coherent pulses accumulation to calculate the fault location by accumulating reflected signal. The simulated results show that this method can effectively improve the Signal to Noise Ratio (SNR), threshold detection level of the fault signal, and also enhance the detection capability of the fault location in long power cable.