Objective To explore the application effects of coils and vascular plug in the interventional embolization treatment of simple pulmonary arteriovenous malformation (PAVM) in the Chinese real-world setting, and compare the persistent occlusion effect and cost-effectiveness of the two types of devices. Methods Simple PAVM patients who underwent interventional embolization at the Department of Respiratory and Critical Care Medicine, West China Hospital of Sichuan University between January 1, 2020 and August 30, 2025 were selected retrospectively. The included patients were divided into the coil group and the vascular occlusion device/combination group according to the type of embolization instrument used in the interventional surgery. Clinical, imaging, procedural, and follow-up data were collected. The primary unit of analysis was PAVM. Primary outcome is durable occlusion rate and recanalization/persistence rate, assessed by strict imaging criteria. Intergroup comparisons, Kaplan-Meier survival analysis, and logistic regression were performed to compare treatment outcomes between coils and vascular plugs and to explore risk factors for persistence. Cost analysis was conducted to compare the cumulative cost required to achieve durable occlusion for each device. Results A total of 34 PAVM in 29 patients were included. The persistence rate was significantly lower in the vascular plug/combination group compared to the coil group (0.0% vs. 47.8%, P=0.006). The vascular plug group demonstrated higher durable occlusion rates at ≥12 months (100.0% vs. 60.9%, P=0.017), along with a significantly longer duration of sustained occlusion (P=0.008). Multivariate logistic regression analysis did not identify independent predictive factors, although the distance from the embolic device to the sac entrance showed a borderline significant association (P=0.080). The cost analysis results showed that although the surgical instrument cost, total material cost, total surgical cost of the vascular occlusion device/combination group were higher (P<0.001). There was no statistically significant difference in the cumulative total cost between the two groups (P=0.066). Conclusions For the treatment of simple PAVM, vascular plugs provide significantly superior long-term occlusion outcomes compared to coils. From a long-term perspective, the advantage of vascular plugs in reducing the need for re-intervention, their overall cost-effectiveness is expected to become more prominent, demonstrating superior value for clinical application and health economics.
The gradient field, one of the core magnetic fields in magnetic resonance imaging (MRI) systems, is generated by gradient coils and plays a critical role in spatial encoding and the generation of echo signals. The uniformity or linearity of the gradient field directly impacts the quality and distortion level of MRI images. However, traditional point measurement methods lack accuracy in assessing the linearity of gradient fields, making it difficult to provide effective parameters for image distortion correction. This paper introduced a spherical measurement-based method that involved measuring the magnetic field distribution on a sphere, followed by detailed magnetic field calculations and linearity analysis. This study, applied to assess the nonlinearity of asymmetric head gradient coils, demonstrated more comprehensive and precise results compared to point measurement methods. This advancement not only strengthens the scientific basis for the design of gradient coils but also provides more reliable parameters and methods for the accurate correction of MRI image distortions.
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.
