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Portal venous tumor emboli is one of the important factors that affect the prognosis of patients with hepatocellular carcinoma (HCC). There are different characters of surgery, interventional therapy, radiation therapy, treatment of local damage, targeted therapy in the treatment of portal venous tumor emboli, but the effects are not ideal. Scholars at home and abroad are exploring a variety of treatment patterns in the treatment of portal venous tumor emboli, to achieve better effect.Predominantly surgical comprehensive treatment can excision of tumor and tumor emboli, improve liver function, improve the quality of survival, prolong survival time. But the operation risk is big. Mainly non-surgical treatment has advantages of little trauma, less risk, and better local control of tumor emboli. But the efficiency, effect, alleviate period is ineffective. Therefore, the best treatment mode should be explored according to the different tumor emboli parting.
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Humans , Carcinoma, Hepatocellular , General Surgery , Liver Neoplasms , General Surgery , Neoplastic Cells, Circulating , Portal Vein , Prognosis , Thrombosis , General SurgeryABSTRACT
Objective To study the results of laparotomy and Cool-tip radiofrequency ablation to treat large liver tumors.Methods Laparotomy and Cool-tip radiofrequency ablation were carried out on 64 patients with large hepatic cancer.To destroy the tumor completely,for tumors of 3.0～4.0 cm in diameter,7 ablations were required; for 4.0～5.0 cm in diameter 15 ablations; for 5.0～6.0 cm in diameter 19 ablations; for 6.0～7.0 cm in diameter 40 ablations.Result The complete necrosis rate of laparotomy and radiofrequency ablation was 93.75％ (60/64).The short-term results were good.Conclusions Laparotomy and Cool-tip multipoint overlapping radiofrequency ablation for large liver tumors (tumor diameter＞3 cm) could result in a high complete necrosis rate and a low complication rate.It is a good radical treatment for unresectable and large liver cancer.
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Objective To investigate the effects of improved end-to-end invagination pancreaticojejunostomy on the occurrence of pancreatic fistula after pancreaticoduodenectomy.Methods The clinical data of 396 patients who received pancreaticoduodenectomy at the Cancer Hospital of Shandong Province from January 2001 to January 2011 were retrospectively analyzed.All patients were divided into the improved group(235 patients)and traditional group(161 patients)according to different anastomotic methods.All the operations were done by the same surgical group,and the digestive tract was reconstructed by the Child method.Patients in the improved group received improved end-to-end invagination pancreaticojejunostomy,and patients in the traditional group received traditional end-to-end anastomosis.The volume of operative bleeding,operation time,incidence of pancreatic fistula and duration of hospital stay of the 2 groups were compared.All data were analyzed using the t test,chisquare test or Fisher exact probability.Results The operative blood loss,operation time and duration of hospital stay were(383 ±56)ml,(7.2 ± 1.0)hours,(21 ±3)days in the improved group,and(381 ±39)ml,(7.0 ± 0.5)hours,(22 ± 5)days in the traditional group,with no significant difference between the 2 groups(t =0.388,1.680,-1.835,P ＞ 0.05).No operative death was detected in the 2 groups,and the overall incidence of pancreatic fistula was 7.6％(30/396).The incidence of pancreatic fistula of the improved group was 0(0/235),which was significantly lower than 18.6％(30/161)of the traditional group(P ＜ 0.05).Patients complicated with pancreatic fistula in the traditional group were cured by drainage,somatostatin administration and parenteral nutrition.Conclusion Improved end-to-end invagination pancreaticojejunostomy can significantly reduce the incidence of pancreatic fistula after pancreaticoduodenectomy.
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For the high rate of relapse and metastasis,the 5-year survival rate in Pancreatic cancer patients is low.Surgery still is a effective treatment in pancreatic cancer.With the deep understanding of the disease,the operation of pancreatic cancer has been improved.In recent years,with the rapid development of laparoscopic techniques,minimally invasive surgery is also applied to the treatment of pancreatic cancer.This review summarizes some pancreatic cancer surgical operations developed in recent years.
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The contour line of human brain was simulated by the curve-fitting methods and then the inner area was discretized by advancing-front methods which was improved at last. The curve-fitting result was similar to the CT picture of the human brain and the discrete result of inner area could be completed quickly by improved advanced-front methods. A finite element model with the contour line of human brain was built primarily which will contribute to the next algorithm study of electrical impedance tomography in human brain.
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Humans , Algorithms , Brain , Finite Element Analysis , Models, Anatomic , Models, NeurologicalABSTRACT
Induced current electrical impedance tomography (ICEIT) is a new branch of electrical impedance tomography (EIT). We have designed and set up a high accuracy ICEIT hardware system with 32 electrodes based on physical phantom, and we have brought forward a new method to reduce the additive electromotive force (EMF) in circuit of the electrode leads. By use of the technique of twisted pair wire, the additive EMF in the circuit of the electrode leads has been reduced to 10% of that before use and the precision of the system has been improved. The precision of the final results is better than 0.5% after 1000 measurement data averaged. Applying the reconstructive algorithm, we have obtained preliminary images based on physical phantom.
Subject(s)
Algorithms , Amplifiers, Electronic , Electric Impedance , Electrodes , Electromagnetic Phenomena , Equipment Design , Models, Theoretical , Signal Processing, Computer-Assisted , Tomography , MethodsABSTRACT
To fit the technological requirements in electrical impedance tomography system, an improved bipolar optocoupler isolation amplifier based on single analog optocoupler was realized. The experimental results illustrates that the full power -3dB bandwidth of this circuit is greater than 800 KHz, the equivalent output noise is lower than 50 uV(RMS), and the linearity at +/- 4 V inputs is lower than 0.01%. In addition to these features, the circuit also have the advantages of simple structure and no distortion caused by mismatch between analog optocouplers.
Subject(s)
Humans , Amplifiers, Electronic , Electric Impedance , Equipment Design , TomographyABSTRACT
The rules of conductance parameters on diseased breast tissue, which change with the driven frequency, are studied by use of electrical impedance scanning. This work is intended to provide a basis for further examination of breast. We have obtained conductance parameters' frequency characteristic of three kinds of breast diseases, i.e. invasive ductal carcinoma, neoplastic hyperplasia, and mastopathia. And by comparison, we find that the frequency characteristic of the diseased breast tissues is different from that of the peripheral normal tissues, and the frequency characteristic shows differences among the three kinds of diseased breast tissues. So, we are able to identify the kind of breast disease by its frequency characteristic.
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Female , Humans , Breast Diseases , Diagnosis , Pathology , Breast Neoplasms , Diagnosis , Carcinoma, Ductal, Breast , Diagnosis , Electric Impedance , Electronics, Medical , Methods , Hyperplasia , DiagnosisABSTRACT
Induced-current electrical impedance tomography (ICEIT) is a newly hot research field in electrical impedance tomography (EIT) because of its advantages of contactless exciting. A preliminary ICEIT system with 3 excitation coils has been accomplished. It includes the constant current source (CCS), power amplifiers, excitation coils,physical phantom, measurement-mode setting circuit, signal measuring block, DAC and digital I/O card. The CCS is accomplished with Direct Digital Synthesis (DDS) technique. Its frequency is 46.875 KHz. Its output current is divided into 16 steps from 0.16 mA to 2.56 mA which can be set by computer. The three driving coils have the same diameter of 50 cm, each coil's inductance is 193.5 microH. The power amplifier can provide 800 mA driving current (f = 46.875 KHz) to the coil under +/- 25 V power supplying. The signal from measurement electrodes is switched to measurement channel which includes IA, BP filter and synchronized demodulator, then the analog signal is converted to digital signal by a 12b A/D Card and the data is acquired by DMA mode. Our experiments show that a distinguish change of signal from the surface electrodes can be acquired by the experimental system when different objects are placed in the physical phantom. And 3 x 31 signals for preliminary imaging have been acquired.
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Humans , Algorithms , Amplifiers, Electronic , Electric Impedance , Electrodes , Electromagnetic Fields , Electromagnetic Phenomena , Image Processing, Computer-Assisted , Phantoms, Imaging , Tomography , MethodsABSTRACT
Objective To compare the performance of novel Ag/AgCl pulverized electrodes with conventional Ag/AgCl coating electrodes in cerebral application of Electrical Impedance Tomography(EIT).Methods Based on the EIT system developed by our group,raw data were measured on a phantom and an adult volunteer,with Ag/AgCl coating electrodes and pulverized electrodes,respectively.The performances of electrode systems were evaluated in contact impedance and two other figures(the high-frequency SNR,HFSNR;the low-frequency SNR,LFSNR).Results Ag/AgCl pulverized electrode plays a better performance in resisting noise and keeping stabilization.Conclusion Ag/AgCl pulverized electrode develops the needs of imaging and monitoring human brains in EIT more availably.
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Objective To study the image processing methods of electrical impedance tomography(EIT) in order to improve the display quality.Methods Evaluate the conductivity of the nodes using the conductivity of the adjacent triangle elements.The conductivity of any point in one triangle element was calculated according to the conductivity of 3 vertexes of the element by 2D linear interpolation method.Results The original blocky images of electrical impedance tomography by the triangle elements can be transformed into smoothing images.Conclusion The visual quality of the images is improved greatly.The image processing method is adaptive to all kinds of images of electrical impedance tomography based on triangle element.
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The complex impedance measurements of human brain tissue in vitro are made by using four-electrode measurement methods in the frequency range from 0.1 Hz to 1 MHz. The Solartron 1255 B frequency response analyzer is used. The frequency response curves of the imaginary part of human brain's complex impedance do not appear as a single peak curve which other bio-tissues show, and the Cole-Cole diagram of human brain is different from the others as well. The construction of the equivalent circuit model obtained is more complex. However, these characteristics of human brain are all the same as rabbit brain's. The equivalent circuit model obtained will be helpful to constructing the equivalent circuit model of human head in the EIT researches.
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Adult , Humans , Male , Brain , Physiology , Electric Impedance , Electrodes , In Vitro Techniques , Models, BiologicalABSTRACT
The in vivo measurements of rabbit brain tissue impedance were taken under both normal and ischemic conditions by using two-electrode measurement method in the frequency range from 0.1 Hz to 1 MHz. The dynamic images about the resistivity of cerebral ischemia were reconstructed based on a 16-electrode system. The results of in vivo measurement showed that the ratio of impedance increased can be as high as 75% at frequencies lower than 10 Hz. In the range from 1 KHz to 1 MHz, the ratio showed a constant value of 15%. The electrical impedance tomography (EIT) images obtained suggested that the regions of impedance changes highly correspond to the position of ischemia. It is confirmed that the brain function changes caused by local deficiency of blood can be detected and imaged by EIT method.
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Animals , Female , Male , Rabbits , Brain , Physiology , Brain Ischemia , Electric Impedance , Tomography , MethodsABSTRACT
Objective To provide the hardware system of EIT with an excellent direct current(DC) power source. Methods The spectrums of the outputs of DC power source and the driving source were analyzed by means of Spectrum Analyzer- E4408B when EIT system was respectively powered by battery, linear power source and switching power source. Based on the numbers and power levels of the spurs of the three power sources and the numbers and power levels of the interferences within the driving source, the influence of the three power sources on the error of measuring was estimated. Meanwhile the EIT system did data acquisition, the overall signal-to-noise-ratio(SNR) of the three power sources at the 18 frequencies were calculated and the influence of the three power sources on the error of measuring was judged. Results With respect to the numbers and power levels of the interferences within the driving source when EIT was powered respectively by the three power sources, the battery output 6 interferences, the highest power of which achieved -78.25 dBm; the linear power source output 6 interferences, the highest power of which achieved -67.11 dBm; the switching power source output 15 interferences, the highest power of which achieved -35.83 dBm. The overall SNRs of the battery at the 18 driving frequencies were higher than that of the linear power source, and the overall SNRs of the linear power source were higher than that of the switching power source. Conclusion The power mode of battery is the best for the hardware of EIT among the three power sources.
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The human skull impedance was quantitatively measured by means of Frequency Response Analyzer and its software. The impedance-frequency response curves of human skull were obtained. By analyzing the curves, we found that the characteristic frequency of human skull should be around 10 KHz.
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Adult , Humans , Middle Aged , Electric Impedance , Skull , Physiology , Time FactorsABSTRACT
It is the intent of this paper to develop better reconstruction algorithm for electrical impedance tomography (EIT). Simulation study of the reconstruction algorithm based on the sensitivity theorem is made and the reconstruction algorithm is compared with other normal algorithms. The results indicate that sensitivity method as a kind of static reconstruction algorithm has higher accuracy and speed of iteration, so it is worth researching for laboratory modality work.
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Algorithms , Computer Simulation , Electric Impedance , Tomography , MethodsABSTRACT
Objective To investegate the influencing factors of intra-abdominal infectious complications after pancreatoduodenectomy(PD). Methods The postoperative intra-abdominal infectious complications occurrence rate and the influencing factors after PD in 196 patients in recent 7 years were retrospectively analyzed.Results After PD,the rate of postoperative intra-abdominal infections was significantly higher than the rate of other complications. The rate of intra-abdominal infections in patients with near normal pancreatic remnent and with pulmonary infections were significantly higher than those in with harder pancreatic remnant and without pulmonary infections(P