scholarly journals Electrical Characterization of Pork Tissue Measured by a Monopolar Injection Needle and Discrete Fourier Transform based Impedance Measurement

2019 ◽  
Vol 9 (19) ◽  
pp. 4049 ◽  
Author(s):  
Abbasi Aitzaz ◽  
Junsub Kim ◽  
Taehee Kim ◽  
Ki Park ◽  
Sungbo Cho
Keyword(s):  
Fourier Transform ◽  
Discrete Fourier Transform ◽  
Measurement System ◽  
Electrical Impedance ◽  
Impedance Measurement ◽  
Injection Therapy ◽  
Target Tissue ◽  
Injection Needle ◽  
Image Guided ◽  
Monopolar Injection

Ultrasonography or fluoroscopy-guided needle injection has been used for intra-articular injection therapy against adhesive capsulitis and joint diseases. To improve the image-guided intra-articular injection therapy, electrical impedance measurement based positioning of the needle tip in the target tissue can be applied. The feasibility of the discrimination for the tissue layer at which the disposable monopolar injection needle tip position was investigated using the discrete Fourier transform (DFT)-based impedance measurement system and the ultrasound imaging device. The electrical impedance spectra of the pork tissue measured in the frequency range of 200 Hz to 50 kHz were characterized by designed equivalent circuit modeling analysis. The normalized impedance data of the tissue layers (dermis, hypodermis, and muscle) were significantly different from each other (p-value < 0.001). The DFT-based impedance measurement system with a monopolar injection needle can be complementary to the image-guided intra-articular injection therapy.

scholarly journals Lock-in Amplifier-Based Impedance Detection of Tissue Type Using a Monopolar Injection Needle

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4614 ◽  
Author(s):  
Kim ◽  
Abbasi ◽  
Kim ◽  
Park ◽  
Cho
Keyword(s):  
Electrical Impedance ◽  
Impedance Measurement ◽  
Muscle Layer ◽  
Injection Therapy ◽  
Tissue Type ◽  
P Value ◽  
Injection Needle ◽  
Needle Position ◽  
Monopolar Injection ◽  
Lock In

For successful intra-articular injection therapy, it is essential to accurately position the tip of the injection needle into the target joint area while administering the drug into the affected tissue. In this study, we investigated the feasibility of a monopolar injection needle and lock-in amplifier (LIA)-based impedance measurement system for detecting the tissue type where the needle tip is located. After positioning the monopolar injection needle tip into the dermis, hypodermis, or muscle layer of pork tissue, the electrical impedance was measured in the frequency range of 10 Hz to 10 kHz. We observed a difference in the results based on the tissue type where the needle was positioned (p-value < 0.01). Therefore, the monopolar injection needle with electrical impedance measurement can be used to improve intra-articular injection therapy through non-destructive and real-time monitoring of the needle position in the tissues.

scholarly journals Real-Time Impedance Detection of Intra-Articular Space in a Porcine Model Using a Monopolar Injection Needle

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4625
Author(s):  
Muhammad Aitzaz Abbasi ◽  
Hwijung Kim ◽  
Somasekhar R. Chinnadayyala ◽  
Ki Deok Park ◽  
Sungbo Cho
Keyword(s):  
Electrical Impedance ◽  
Porcine Model ◽  
Saline Solution ◽  
Impedance Measurement ◽  
Knee Joints ◽  
Drug Injection ◽  
Good Efficiency ◽  
Injection Needle ◽  
Monopolar Injection

Rheumatoid arthritis and osteoarthritis can be treated through specific drug injection into the intra-articular space. Several failures during drug injection attempts with conventional fluoroscopy and ultrasonography in a small area of the intra-articular space have been reported. In this work we present an innovative impedance measurement-based method/algorithm for needle tip positioning to enhance image-guided intra-articular vaccination treatment. A novel algorithm for detecting the intra-articular space in the elbow and knee joints of a live porcine model is reported. An impedance measurement system was developed for biological tissue measurement. The electrical impedance in the intra-articular space was monitored and the needle tip was examined by ultrasonography. The contrast dye was vaccinated and checked using fluoroscopy to confirm that the dye was properly inoculated in the cavity. The electrical impedance was estimated for various needle inclusion profundity levels in saline solution, which were broadly used to evaluate the proposed device for in vivo examinations. Good efficiency was observed in the impedance-based measurements using a monopolar injection needle for intra-articular therapy. To enhance the needle tip positioning for intra-articular therapy, the intended impedance measurement device with a monopolar injection needle can be used as a complement to existing modalities.

Measurement of loudspeaker mechanical impedance by changing the sound load at the throat of loudspeaker

2021 ◽  
Vol 263 (1) ◽  
pp. 5457-5466
Author(s):  
Shichun Huang ◽  
Liang Yu ◽  
Weikang Jiang
Keyword(s):  
Measurement System ◽  
Electrical Impedance ◽  
Structural Parameters ◽  
Impedance Measurement ◽  
Mechanical Impedance ◽  
Coupling Model ◽  
Acoustic Energy ◽  
Mathematical Relationship ◽  
Radiation Impedance ◽  
Acoustic Coupling

A loudspeaker is a device that converts electrical energy into acoustic energy by coupling between electrical impedance, mechanical impedance, and radiation impedance. The loudspeaker electro-mechanical-acoustic coupling model provides the experimental feasibility to measure the characteristic parameters. In this paper, an economical and practical measurement method of loudspeaker mechanical impedance is proposed. First, the mathematical relationship between loudspeaker electrical impedance and mechanical impedance is obtained based on the loudspeaker electro-mechanical-acoustic coupling model. Second, two electrical impedances with different known radiation impedance are measured by using a developed measurement system. Finally, the real and imaginary parts of the mechanical impedance are obtained according to the mathematical relationship. This method neither assumes that the loudspeaker mechanical impedance is constant in a frequency band nor does it build FEM models based on structural parameters. A loudspeaker is measured by using a developed measurement system. The result shows that the mechanical impedance and the force factor are functions of frequency. Moreover, a radiation impedance measurement is performed to verify the feasibility and accuracy of the proposed method.

scholarly journals Development of an electrical impedance based spirometer

2018 ◽  
Vol 9 (1) ◽  
pp. 17-27
Author(s):  
Md Anas Ali ◽  
M Abdul Kadir ◽  
K Siddique e Rabbani
Keyword(s):  
Measurement System ◽  
Electrical Impedance ◽  
Medical Physics ◽  
Impedance Measurement ◽  
Current Drive ◽  
The Body ◽  
Constant Current ◽  
Forced Expiration ◽  
Voltage Measurement ◽  
Asthma Patients

Spirometry, or measurement of respiration conventionally involves measurement of the time variation of volume or flow of air breathed in or out through the mouth using an air-flow sensor. Electrical impedance of thorax changes during breathing and conceptually this modality should be applicable in spirometry, but no attempts have been made so far. This paper describes the development of an electrical impedance based spirometer placing electrodes on four limbs so that the whole lung volume may contribute to the measurement. An impedance based measurement system (IBS) consisting of a constant current drive at 11 kHz and necessary voltage measurement circuitry was designed and developed for this purpose. A portable oscilloscope (PicoScope 2208A) was used for acquisition of the measured voltage signal to a PC and an algorithm in Matlab software was used to demodulate the time varying impedance from a carrier signal. The variation of impedance with time during forced expiration as measured by the implemented impedance measurement system was compared with that obtained using a standard bellows type commercial spirometer (Vitalograph) on eight volunteers, between 22 and 32 years of age. The subjects included smokers, non-smokers, and asthma patients. Repeatability of the measurements were satisfactory. The correlation coefficient between the spirogram obtained using the IBS and that obtained using standard spirometer varied from 0.81 to 0.99 indicating preliminary success of the proposed technique. However, a possible source of error is the bending of the body during forced expiration which, if prevented, may give a better outcome.Bangladesh Journal of Medical Physics Vol.9 No.1 2016 17-27

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