Differences in structure changes in the retina of a rabbit after the action the unipole high-frequency electro-welding of biological tissues and diode laser coagulation according to the data of the optical coherent tomography

The aim: To analyze and evaluate the efficacy of CDLLV treatment, using high-frequency endovascular welding (EVW), endovenous laser coagulation (EVLC) and catheter microfoam echosclerotherapy. Materials and methods: We have treated 329 patients with CDLLV C2-C6 functional classes according to the Clinical Etiological Anatomical Pathophysiology. Of these, 102 patients had vertical reflux eliminated by EVW, in 112 – by EVLC, and in 115 – by catheter microfoam echosclerotherapy. Results: In the EVW group 3 patients (2.94%) had a partial recanalization of coagulated veins 3 months after the procedure. In EVLC group 2 patients (1.79%) also had partial recanalization group after 6 months. In the group of catheter microfoam echosclerotherapy partial recanalization occurred in 3 patients during 3 months of observation, in the period of 6 months – in 2, in the period of 12 months – in 9, in total – in 14 patients (12.17%). The EVW and EVLC methods showed high efficacy of vertical reflux elimination on the great and small subcutaneous veins (GSV/SSV) in CDLLV and have no fundamental differences in the immediate and long-term results of treatment. Microfoam catheter echosclerotherapy leads to a greater number of recanalisations, compared with EVW and EVLC. Conclusions: High-frequency endovenous welding results in complete fibrotic GSV/SSV transformation in 97.06% of patients. Endovascular laser coagulation results in complete fibrotic GSV/SSV transformation in 98.21% of patients. Elimination of vertical reflux by microfoam echosclerotherapy results in complete fibrotic GSV/SSV transformation in 87.83% of patients.

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A THREE-PHASE INDUCTIVE SENSOR FOR IN VIVO MEASUREMENT OF ELECTRICAL ANISOTROPY OF BIOLOGICAL TISSUES

Contemporary Materials ◽

10.7251/comen1401001k ◽

2014 ◽

Vol 5 (1) ◽

Author(s):

Yukio Kosugi ◽

Tadashi Takemae ◽

Hiroki Takeshima ◽

Atsushi Kudo ◽

Kazuyuki Kojima ◽

...

Keyword(s):

Magnetic Field ◽

Electrical Conductivity ◽

High Frequency ◽

Reference Signal ◽

Biological Tissues ◽

Electrical Anisotropy ◽

Conductivity Anisotropy ◽

In Vivo Measurement ◽

Surgical Operations

Biological tissue will have anisotropy in electrical conductivity, due to the orientation of muscular fibers or neural axons as well as the distribution of large size blood vessels. Thus, the in vivo measurement of electrical conductivity anisotropy can be used to detect deep-seated vessels in large organs such as the liver during surgeries. For diagnostic applications, decrease of anisotropy may indicate the existence of cancer in anisotropic tissues such as the white matter of the brain or the mammary gland in the breast. In this paper, we will introduce a new tri-phase induction method to drive rotating high-frequency electrical current in the tissue for the measurement of electrical conductivity anisotropy. In the measurement, three electromagnets are symmetrically placed on the tissue surface and driven by high-frequency alternative currents of 0 kHz, modulated with 1 kHz 3-phase signals. In the center area of three magnets, magnetic fields are superimposed to produce a rotating induction current. This current produces electrical potentials among circularly arranged electrodes to be used to find the conductivity in each direction determined by the electrode pairs. To find the horizontal and vertical signal components, the measured potentials are amplified by a 2ch lock-in amplifier phase-locked with the 1 kHz reference signal. The superimposed current in the tissue was typically 45 micro Amperes when we applied 150 micro Tesla of magnetic field. We showed the validity of our method by conducting in vitro measurements with respect to artificially formed anisotropic materials and preliminary in vivo measurements on the pig’s liver. Compared to diffusion tensor MRI method, our anisotropy sensor is compact and advantageous for use during surgical operations because our method does not require strong magnetic field that may disturb ongoing surgical operations.

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