ObjectiveTo explore the application value of CT-guided microcoil localization in pulmonary nodule (diameter≤15 mm) surgery.MethodsThe clinical data of 175 patients with pulmonary nodules who underwent single utility port video-assisted thoracoscopic surgery at Nanjing Drum Tower Hospital from August 2018 to December 2019 were retrospectively analyzed. According to whether CT-guided coil localization was performed before operation, they were divided into a locating group and a non-locating group. There were 84 patients (34 males, 50 females, aged 57.8±8.8 years) in the locating group and 91 patients (46 males, 45 females, aged 57.6±10.8 years) in the non-locating group. The localization success rate, localization time, incidence of complications, surgical and postoperative conditions were analyzed between the two groups.ResultsAll 84 patients in the locating group were successfully located, and localization time was 19.0±3.6 minutes. Among them, 19 (22.6%) patients had a small pneumothorax, 4 (4.8%) pulmonary hemorrhage and 2 (2.4%) coil shift; 6 (7.1%) patients had mild pain, 3 (3.6%) moderate pain and 1 (1.2%) severe pain. Sex (P=0.181), age (P=0.673), nodule location (P=0.167), nature of lesion (P=0.244), rate of conversion to thoracotomy (P=0.414), rate of disposable resection of nodules (P=0.251) and postoperative hospital stay (P=0.207) were similar between the two groups. There were significant differences in nodule size (P<0.001), nature of nodule (P<0.001), the shortest distance from nodule to pleura (P<0.001), operation time (P<0.001), lung volume by wedge resection (P=0.031), number of staplers (P<0.001) and total hospitalization costs (P<0.001) between the two groups.ConclusionCT-guided microcoil localization has the characteristics of high success rate, and is simple, practicable, effective, safe and minimally invasive. Preoperative CT-guided microcoil localization has important clinical application value for small pulmonary nodules, especially those with small size, deep location and less solid components. It can effectively shorten the operation time, reduce surgical trauma and lower hospitalization costs, which is a preoperative localization technique worthy of popularization.
Magnetic induction method aims at the noninvasive detection of liver iron overload by measuring the hepatic magnetic susceptibility. To solve the difficulty that eddy current effects interfere with the measurement of magnetic susceptibility, we proposed an improved coil system based on the static field magnetization principle in this study. We used a direct current excitation to eliminate the eddy current effect, and a rotary receiver coil to get the induced voltage. The magnetic field for a cylindrical object due to the magnetization effect was calculated and the relative change of maximum induced voltage was derived. The correlation between magnetic susceptibility of object and maximum magnetic flux, maximum induced voltage and relative change of maximum induced voltage of the receiver coil were obtained by simulation experiments, and the results were compared with those of the theory calculation. The contrast shows that the simulation results fit the theory results well, which proves our method can eliminate the eddy current effect effectively.
Objective To investigate the technical feasibility and effectiveness of intraoperative sac embolizaion with coils and fibrin glue for preventing type Ⅱ endoleak after endovascular aneurysm repair (EVAR). Methods A patient with abdominal aortic aneurysm (AAA), which had high risk of type Ⅱ endoleaks, was treated with combined packing of coils and fibrin glue in order to prevent type Ⅱ endoleak after EVAR. Percutaneous catheter preset and balloon occlusion were used to ensure accurate packing. Results At the end of the operation, the angiography showed that the blood flow of the stent and distal artery was unobstructed, there was no type Ⅰ and Ⅲ endoleaks, and delayed angiogram showed no collateral circulation of aneurysm. The procedure was successful. The operative duration was 120 min and the blood loss was only 20 mL. No complications such as colonic ischemia and ectopic embolism occurred, and the patient was discharged on 3 days after operation. At 6 months after follow-up, the computerized topographic angiography showed that the aneurysm cavity was completely thrombotic, without type II endoleak, and the diameter and volume of aneurysm were reduced. Conclusions The technique of intraoperative sac embolizaion with coils and fibrin glue during EVAR is safe and effective to prevent postoperative endoleaks, which is simple and feasibility. Intraoperative indwelling catheter and balloon blocking are the key points of successful implementation of this technique.
In the development of radio frequency (RF) coils for better quality of the mini-type permanent magnetic resonance imager for using in the small animal imaging, the solenoid RF coil has a special advantage for permanent magnetic system based on analyses of various types of RF coils. However, it is not satisfied for imaging if the RF coils are directly used. By theoretical analyses of the magnetic field properties produced from the solenoid coil, the research direction was determined by careful studies to raise further the uniformity of the magnetic field coil, receiving coil sensitivity for signals and signal-to-noise ratio (SNR). The method had certain advantages and avoided some shortcomings of the other different coil types, such as, birdcage coil, saddle shaped coil and phased array coil by using the alloy materials (from our own patent). The RF coils were designed, developed and made for keeled applicable to permanent magnet-type magnetic resonance imager, multi-coil combination-type, single-channel overall RF receiving coil, and applied for a patent. Mounted on three instruments (25 mm aperture, with main magnetic field strength of 0.5 T or 1.5 T, and 50 mm aperture, with main magnetic field strength of 0.48 T), we performed experiments with mice, rats, and nude mice bearing tumors. The experimental results indicated that the RF receiving coil was fully applicable to the permanent magnet-type imaging system.
The therapeutic effects of transcranial magnetic stimulation (TMS) are closely related to the structure of the stimulation coil. Based on this, this study designed an A-word coil and proposed a multi-strategy fusion multi-objective slime mould algorithm (MSSMA) aimed at optimizing the stimulation depth, focality, and intensity of the coil. MSSMA significantly improved the convergence and distribution of the algorithm by integrating a dual-elite guiding mechanism, a hyperbolic tangent control strategy, and a hybrid polynomial mutation strategy. Furthermore, compared with other stimulation coils, the novel coil optimized by the MSSMA demonstrates superior performance in terms of stimulation depth. To verify the optimization effects, a magnetic field measurement system was established, and a comparison of the measurement data with simulation data confirmed that the proposed algorithm could effectively optimize coil performance. In summary, this study provides a new approach for deep TMS, and the proposed algorithm holds significant reference value for multi-objective engineering optimization problems.
Objective To systematically review the effectiveness and safety of power chain vs. nickel titanium coil springs in closing dental extraction space. Methods Databases including PubMed, EMbase, The Cochrane Library, Chinese Biomedicine Literature Database, Chinese Scientific Journals Full-text Database, and Chinese Journal Full-text Database were searched to collect the randomized controlled trials (RCTs) on comparing power chain with nickel titanium coil springs published before February 2012. Two reviewers independently screened literature, extracted data and assessed the quality of the included studies. Then meta-analysis was conducted using RevMan 5.0 software. Results A total of 4 RCTs involving 122 patients were included. The results of meta-analyses showed that there was a significant difference in the rate of space closure between the two groups (MD=0.30 mm per month, 95%CI 0.17 to 0.44, Plt;0.000 1); The results of subgroup analyses indicated that, both high-quality trials (MD=0.20, 95%CI 0.07 to 0.34, P=0.003) and low quality trials (MD=0.40, 95%CI 0.30 to 0.50, Plt;0.000 01) showed no significant difference in the rate of space closure. Conclusion Current clinical evidence indicates nickel titanium coil spring is superior to power chain in the rate of space closure, but its long-term effect still needs to be proved by more large-scale RCTs.
ObjectiveTo identify risk factors for severe elastic recoil after percutaneous transluminal angioplasty (PTA) in the femoropopliteal artery disease based on intravascular ultrasound (IVUS) imaging and to develop a risk prediction model. MethodsA retrospective analysis was conducted on the clinical data from the patients with femoropopliteal artery disease treated at the First Affiliated Hospital of Chongqing Medical University from September 2020 to February 2022. Based on the IVUS images, a multivariate logistic regression analysis was conducted to identify the risk factors for severe elastic recoil in the patients with femoropopliteal artery disease after PTA. A nomogram prediction model was established to predict the occurrence of severe elastic recoil, and the area under receiver operating characteristic curve (AUC) was used to evaluate its ability to distinguish the occurrence of severe elastic recoil, which was validated using a calibration curve. ResultsA total of 34 patients with femoropopliteal artery disease who received PTA treatment were enrolled. Of the 803 vessel slices were analyzed, 451 (56.16%) demonstrated severe elastic recoil on IVUS imaging. The multivariate logistic regression analysis showed that the increased plaque burden, luminal eccentric index, external elastic membrane remodeling index, and the external elastic membrane-balloon area ratio were the risk factors for the occurrence of severe elastic recoil (P＜0.05). The AUC of the nomogram prediction model based on these risk factors exhibited moderate discrimination [AUC (95%CI)=0.775 (0.732, 0.818)]. The predicted probability of the nomogram model for severe elastic recoil was in a good agreement with the actual probability (P=0.862). ConclusionThe severe elastic recoil prediction model developed in this study, based on IVUS imaging data, can effectively identify high-risk factors for severe elastic recoil after PTA in patients with femoropopliteal artery disease, demonstrating a moderate predictive discrimination capability.
For rat spinal magnetic resonance imaging (MRI) experiments, due to the lower main magnetic field strength, shallower detected depth and poor spatial compatibility of the traditional radio frequency (RF) coil, the image signal-to-noise ratio (SNR) of rat spinal was rather lower. In this paper, a RF coil for rat spinal MRI at 9.4 T was developed to improve the image quality and at the same time to avoid the space limitation while scanning in special conditions (cardiac catheterization, etc.). In this article, open birdcage structure was built and magnetic field distribution was calculated. The phantom and rat spine MRI imaging were experimented at 9.4 T to verify the advantage of the coil in rat spine MRI application.
Currently, transcranial magnetic stimulation (TMS) has been widely used in the treatment of depression, Parkinson’s disease and other neurological diseases. To be able to monitor the brain’s internal activity during TMS in real time and achieve better treatment outcomes, the researchers proposed combining TMS with neuroimaging methods such as magnetic resonance imaging (MRI), both of which use Tesla-level magnetic fields. However, the combination of strong current, large magnetic field and small size is likely to bring physical concerns which can lead to mechanical and thermal instability. In this paper, the MRI static magnetic field, the TMS coil and human head model were built according to the actual situations. Through the coupling of the magnetic field and the heat transfer module in the finite element simulation software COMSOL, the force and temperature of the TMS coil and head were obtained when the TMS was used in combination with MRI (TMS-MRI technology). The results showed that in a 3 T MRI environment, the maximum force density on the coil could reach 2.51 × 109 N/m3. Both the direction of the external magnetic field and the current direction in the coil affected the force distributions. The closer to the boundary of the external magnetic field, the greater the force. The magnetic field generated by the coil during TMS treatment increased the temperature of the brain tissue by about 0.16 °C, and the presence of the MRI static magnetic field did not cause additional thermal effects. The results of this paper can provide a reference for the development of the use guidelines and safety guidelines of TMS-MRI technology.
ObjectiveTo investigate treatment methods and effect of endovascular interventional therapy for visceral artery aneurysms.MethodsThe clinical data of 32 patients with visceral artery aneurysms, who were treated in the No. 960 Hospital of PLA from February 2011 to April 2018, were retrospectively analyzed. It was proveded by the CT or digital subtraction angiography before the interventional therapy. The implantation of covered stent, coil embolization together with stent implantation, double stents placement or pure coil embolization were performed. The postoperative antithrombotic therapy was adopted in the patients accepted the stent implantation. The CT angiography was performed on the month of 1, 6, 12, 24 or the patient was uncomfortable after the treatment to evaluate the obstruction condition of the aneurysms, stent blood flow, and branches arteries, etc..ResultsThe success rate of the endovascular interventional therapy was 100%. In the 11 patients underwent the implantation of covered stent, the postoperative angiography showed that the stent lumen was patent and the aneurysm was not visualized. In the 9 patients underwent the coil embolization together with stent implantation and 3 patients underwent the double stents placement, the postoperative angiography results of the aneurysm showed that it was faintly visualized and the branch arteries were not involved. In the 9 patients underwent the pure coil embolization, the postoperative angiography showed that the aneurysm was not visualized. No perioperative mortality or procedure related complications occurred. No case was lost during the follow-up of a median period of 25.5 (6–48) months. During the follow-up, one patient developed the mild abdominal pain in one month, which disappeared after the symptomatic medication management. Except for 1 patient developed the mild stent stenosis (<30%) on the 12th month after the procedure, the stent and the branch arteries of the other patients were completely patent, and no aneurysms recurred.ConclusionFor treatment of visceral artery aneurysms, endovascular interventional therapy is safe and effective and shows an excellent short-term and mid-term effects.
