RSNA 2014 

Abstract Archives of the RSNA, 2014


SSA20-04

MR-compatibility of Peripheral Self Expanding Nitinol Stents for 1.5 T and 3.0 T: Measuring RF Induced Heating and MR-artifact according to ASTM Standard F2182-11a and F2119-07

Scientific Papers

Presented on November 30, 2014
Presented as part of SSA20: Physics (Non-Conventional Techniques)

Participants

Felix V. Guettler, Presenter: Nothing to Disclose
Andreas Heinrich, Abstract Co-Author: Nothing to Disclose
Florian Schlesies, Abstract Co-Author: Nothing to Disclose
Ulf Karl Martin Teichgraeber MD, Abstract Co-Author: Research Consultant, W. L. Gore & Associates, Inc Research Consultant, Siemens AG Research Consultant, CeloNova BioSciences, Inc Research Consultant, General Electric Company

PURPOSE

The purpose of this study is to measure artifacts in MR-images and radiofrequency-induced heating at 1.5T and 3T for modern and most commonly used stents in vascular angiography according to standardized test methods of the American Society for Testing and Materials (ASTM). Furthermore, the MRI-based measurability of the lumen was assessed.

METHOD AND MATERIALS

Currently, 36 peripheral self expanding nitinol stents with a diameter between 5-8mm and a length between 30-250mm from seven manufacturer (Biotronik, Boston Scientific, Gore, IDEV, Medtronic, OptiMed, Terumo) for peripheral arterial disease were compared on a 1.5T and 3T MRI (Magnetom Avanto and Trio, Siemens, Erlangen, Germany). The signal loss was measured according to ASTM F2119-07 for a TSE (TR/TE 500/26ms) and GRE (TR/TE 100/15ms) sequence. The visualization of lumen was determined the same way. The stents were placed parallel and perpendicular to the static magnetic field (B0). For safety aspects, the radiofrequency-induced heating was measured according to ASTM F2182-11a with a TrueFISP (TR/TE 3.04/1.52ms, scan time 15min).

RESULTS

There are significant differences in visibility of lumen for the stent models. For the TSE sequence, the visualization of lumen varies between 15.59±15.16% and 99.78±5.78% (parallel to B0) respectively 0.00±0.00% and 88.21±10.63% (perpendicular to B0) as well as for the GRE sequence between 0.00±0.00% and 76.50±2.74% (parallel) respectively 0.00±0.00% and 68.12±3.35% (perpendicular). For a B0 of 1.5T and 3T, the visualization of lumen differs between 0.00% and 43.12%. The maximum signal loss above the actual diameter was 4.30±0.80mm (TSE) and 8.50±1.00mm (GRE). The maximum change in temperature caused by induced heating varies between 1.70±0.10°C and 13.90±0.10°C. Only two stent models show no significant heating.

CONCLUSION

The MR-based lumen depends besides MR-sequence and orientation to B0 on material, dimension and structure of stent model. Also the RF-induced heating depends on these stent characteristics, however the dimension in dependence of field strength is the decisive factor for the heatability.

CLINICAL RELEVANCE/APPLICATION

With none or very limited artifacts, MR-based measurement of the in stent-lumen is feasible for a broad spectrum of clinically used MR-sequences.

Cite This Abstract

Guettler, F, Heinrich, A, Schlesies, F, Teichgraeber, U, MR-compatibility of Peripheral Self Expanding Nitinol Stents for 1.5 T and 3.0 T: Measuring RF Induced Heating and MR-artifact according to ASTM Standard F2182-11a and F2119-07.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018088.html