Association between magnetic resonance imaging of carotid artery and coronary stenosis detected by computed tomography angiography.

OBJECTIVE: To investigate the correlation between carotid artery stenosis (CAS) measured by magnetic resonance imaging (MRI) and the coronary stenosis (CS) determined by computed tomography angiography (CTA). METHODS: In this prospective study, 42 subjects diagnosed with coronary artery disease (CAD) underwent MRI and CTA examinations. The severity degree and number of CAS, the score, detection rate and type of carotid plaque, and also the severity degree and number of CS were assessed. Spearman's rank correlation test was used to evaluate the correlation between CAS and CS. RESULTS: CS was detected in 42 (100%) subjects, while CAS was detected in 36 (85.7%) subjects. Distribution of CAS severity grades in multiple-vessel group was significantly different from other groups, which with more moderate and severe stenosis (p < 0.05). A positive and significant correlation between the CAS severity and CS severity (r = 0.612, p < 0.05), and the number of involved coronary vessels (r = 0.572, p < 0.05) were observed, respectively. Both detection rate (r = 0.587, p < 0.05) and score (r = 0.735, p < 0.05) of carotid plaque showed a good correlation with the number of involved coronary vessels. After carotid MRI, 71 carotid plaques were detected in 42 subjects, with an incidence rate of 9.9% in subjects with mild CS, 18.3% in moderate CS and 71.8% in severe CS. CONCLUSION: Correlation between CAS measured by MRI and CS determined by CTA was identified in present study. These results indicated that the non-invasive CAS evaluation employing the MRI may be clinically useful for the assessment of CS.

[Spectroscopic Study on a Direct-Current Driving Plasma Jet in Argon at Atmospheric Pressure].

With a discharge device in a hollow-needle and plate electrode configurations, an atmospheric pressure uniform plasma plume is generated by DC voltage excitation in the ambient air with argon as working gas. The plasma plume is a pulsed discharge despite a direct current voltage is applied through measurements by optical and electrical methods. In order to explain the formation mechanism of the pulse, spatially resolved signals emitted from the plume were detected. It was found that the plasma plume denoted as the luminous layer propagates (a plasma bullet) from the hollow needle to the plate electrode except for the corona discharge in the vicinity of the hollow needle tip. Optical emission spectroscopy is used to investigate the excited electron temperature of the plasma plume as a function of the applied voltage or the spatial distribution of the excited electron temperature. The results show that the excited electron temperature (about 3 eV) increases with increasing applied voltage. Moreover, it increases with the increasing distance along the gas flow under constant voltage.

[Glow Discharge Characteristics of Hollow Needle-Plate Electrode in Atmospheric Pressure Argon].

Atmosphere pressure uniform plasma has the broad application prospect in the industrial field. Using hollow needle cathode-plate anode device excited by direct-current voltage, a uniform and stable glow discharge is generated at atmospheric pressure in ambient air with argon used as working gas. The influence of the experimental parameters (including gas flow rate and the gas gap width) on discharge has been investigated by optical method. It can be found that a glow-discharge plasma column can bridge the two electrodes. The plasma column is uniform, and no filaments can be discerned. Near the plate electrode, the diameter of the plasma column is largest of all positions. The maximal diameter of the plasma column increases with increasing the discharge current or the gas flow rate. Through electrical method, the voltage-current characteristic has been investigated. It has been found that the discharge voltage decreases with increasing the current which is similar with the characteristic of glow discharge in low pressure. It increases with increasing the gas gap width or the gas flow rate. By analyzing the optical emission spectrum scanning from 330 to 450 nm emitted from the direct-current glow discharge, the molecular vibrational temperature and the intensity ratio of spectral lines I391.4/I337.1 have been investigated as functions of the gas flow rate and gas gap width. Results indicate that both the vibrational temperature and the intensity ratio of spectral lines I391.4/I337.1 decrease with increasing the gas flow rate or the gas gap width. In addition, the molecular vibrational temperature and the intensity ratio of spectral lines I391.4/I337.1 have been investigated in spatial resolution along the direction of gas flow (plasma column axial), and give a qualitative analysis as well. It is found that the vibrational temperature and the average electron energy increase with increasing the distance from the hollow needle cathode. These results are important to the industrial applications of glow discharge.

[Investigation of a jet operated in atmospheric pressure argon by optical emission spectroscopy].

A uniform plasma plume was generated in a coaxial dielectric barrier discharge jet through blowing argon into the ambient air at atmospheric pressure. The plasma plume was uniform along the direction of the gas flow. The length of the plasma plume was investigated as a function of the peak voltage, the driving frequency and the gas flow rate. It was found that with increasing the gas flow rate, the plume length increases when the flow rate is lower than 4 L x min(-1), and decreases when it is higher than 4 L x mic(-1). Under constant gas flow rate, the length of the plasma plume increases with the increase in the peak value of the applied voltage and the driving frequency. According to the discharge theory and based on the analysis of the turbulence and the advection, a qualitative explanation was given for the variance of plume length as functions of the experimental parameters. Results also show that there is a discharge pulse for the plasma plume in every positive half cycle, while there is no pulse in negative half cycle. The coaxial dielectric barrier discharge shows two pulses in every positive half cycle and a pulse in every negative half cycle. Analyzing these experimental phenomena mentioned above, a formation mechanism of the plasma plume was proposed. The optical emission spectra were obtained for both the coaxial dielectric barrier discharge and the plasma plume. There was no apparent difference except that some emission lines from reactive species such as OH and N2 were found in the plasma plume. Using the first negative band of, the rational temperature of the plasma plume was measured. Results show that the rational temperature of the plasma plume decreases away from the jet nozzle, and increases with increasing the peak value of the applied voltage.

[Spectroscopic characteristics of DC excited atmospheric pressure glow discharges generated in a needle-plate electrode device and a needle-water electrode one].

Glow discharge characteristics in two discharge devices, i.e. in a needle-plate electrode geometry and a needle-water electrode one were compared by using spectroscopic method. Results show that the different emission regions were found in both discharges generated by the two devices. From the cathode to the anode, there are a cathode glow region, cathode dark glow, a positive column, and an anode glow region. The anode dark region can be clearly discerned in the glow discharge in the needle-plate electrode device, while it almost cannot be found in the needle-water electrode discharge. Comparing the current-voltage characteristics of the two glow discharges, it was found that the voltage across the electrodes decreases with increasing the discharge current in both discharge devices, while the voltage in the needle-water glow discharge is higher than that of the needle-plate one at the same current value. The current-voltage curves have a negative slope and their current densities lie in the range from 10-5 to 10-4 A? cm-2, which indicates that a normal glow discharge mechanism was involved in the two discharges. Comparing the optical spectra scanning from 300nm to 800nm and emitted from the whole normal glow discharge in the two electrode devices, similar spectral lines from the two discharges can be found on the optical emission spectrum, including the second positive system of nitrogen molecules (337.1nm) and the first negative system of nitrogen molecular ions (391.4nm). However, the intensity ratio of spectral lines is different. The intensity ratio (391.4nm to 337.1nm) and vibrational temperature were investigated at different locations. It was found that the intensity ratio of the needle-water electrode discharge is larger than that of the needle-plate electrode discharge at the same location. Furthermore, the vibrational temperature in the needle-water electrode discharge is higher than that of the needle-plate one at the same location.

[Influence of pressure on plasma temperature of octagon structure in dielectric barrier discharge].

Octagon structure consisting of the spots and lines was firstly observed in discharge in argon and air mixture by using a dielectric barrier discharge device with water electrodes. Plasma temperatures of the spots and lines in octagon structure at different gas pressure were studied by using optical emission spectra. The emission spectra of the N2 second positive band (C3IIu-->B3IIg)were measured, and the molecule vibrational temperatures of the spots and lines were calculated by the emission intensities. Based on the relative intensity of the line at 391.4 nm and the N2 line at 394.1 nm, the average electron energy of the spots and lines were investigated. The spectral lines of Ar I 763.26 nm ((2)P6-1Ss) and 772.13 nm ((2)P2-->1S3) were chosen to estimate electron excitation temperature of the spots and lines by the relative intensity ratio method. The molecule vibrational temperature, average electron energy, and electron excitation temperature of the lines are higher than those of the spots at the same pressure. The molecule vibrational temperature, average electron energy, and electron excitation temperature of the spots and lines decrease with pressure increasing from 40 to 60 kPa.

[Comparative investigation of the discharge characteristics of a single needle jet and needle-plate jet].

In the present paper, discharge characteristics were studied in atmospheric pressure argon by a single needle jet and needle-plate jet through combination of optical measurement and electrical one. Results show that the length and cross-sectional area of the plasmas generated in the two jets increase with increasing the peak value of the applied voltage. The cross-sectional area generated by needle-plate jet is bigger than that of the single needle jet at the same voltage. A lower inception voltage is needed for the needle-plate jet compared with the single needle jet at the same U(p). Through the spectra emitted from the two jets, electron temperature and vibration temperature wee compared for the plasmas generated by the single needle jet and needle-plate jet, respectively. It can be found that the electron temperature and the vibrational temperature of the two jets increase with increasing U(p). The needle-plate jet has higher values of electron temperature and vibrational temperature than the single needle jet at the same U(p). These results have significant values for the industrial application of the atmospheric pressure plasma jet.

Leiomyosarcoma of the splenic vein: A case report.

Leiomyosarcomas (LMSs) originating from the wall of blood vessels are aggressive and rare neoplasms. The current study describes a case of a 52-year-old man who presented with intermittent abdominal pain without weight loss or diarrhea. Computed tomography of the abdomen identified a 4-cm, solid, heterogeneous tumor in the tail of the pancreas, while a hypodense lesion was also noted in the right hepatic lobe. The patient subsequently underwent splenic pedicle tumor resection, splenectomy and liver tumor resection. Notably, immunohistochemical and histological analyses identified LMS, which had originated from the smooth muscle of the splenic vein. Currently available information regarding LMSs of the splenic vein and their management is also discussed, with the aim of improving diagnostic accuracy.