Inductive coupled vena cava filter (VCF) to improvement of the MRI visualization and intervention

Sentürk Konak, Stephan Michitsch, Klaas Tohnack, Bastian Urban, Andreas Melzer, INSITE med. & Dept of Physical engineering University of Applied Sciences, Gelsenkirchen and Biophan Europe, Castrop Rauxel, Germany

Background

For the execution of MRI controlled implantation and later course of diagnostic control the VCF must be visible in MRI without artifacts. Aim was the development of an implantable and removable filter for the vena cava inferior, by integration of a resonance circuit (RLC) which improved the MRI lead intervention and the diagnostics.

Material & Methods

For the evaluation of the functional principle prototypes were constructed of copper and phosphorus bronze wire. Filters and SMD condenser were connected to form a RLC, these were tuned on the Larmor frequency of approx 42 and approx 64MHz. Customary filters were tested and equipped with RLC. The prototypes were tested in distilled water and 0,9 % NaCL water, endowed with fresh thrombus as well as implanted and removed into a vessel model under MRI. Imaging was performed in 1.0T/1.5T Philips scanner. GRE sequences (TR/TE =50/5ms, FA = 5-60 °, FOV= 150, ST =2mm) were used.

Results

Filter of titanium and Nitinol with supplement RLC are suitable for MRI. By using of Flip Angle smaller then 10° signal amplification more than 400% was achieved. These filters show only minimal artifacts.

Conclusion

By the integration of RLC in Vena Cava filter good signal amplification can be achieved. This technology can be integrated into conventional filter designs to improve visualization and placement under MRI control.

Keywords

MRT active vena cava filter, MRT intervention, Vena cava filter