Dietmar Edvard Kivelitz MD, Presenter: Nothing to Disclose

Jeanette Klemmt, Abstract Co-Author: Nothing to Disclose

Susanne Wagner DVM, Abstract Co-Author: Nothing to Disclose

Joerg Schnorr MD, PhD, Abstract Co-Author: Nothing to Disclose

Rainer Wetzler PhD, Abstract Co-Author: Nothing to Disclose

Matthias Taupitz MD, PhD, Abstract Co-Author: Nothing to Disclose

Andreas Melzer MD, Abstract Co-Author: Nothing to Disclose

Bernd K. Hamm MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

– Inductively coupled coils for magnetic resonance imaging (MRI) can be implanted and function as stents in animal experiments. The signal-to-noise ratio within these stents is improved at MRI. The present study was performed to evaluate the long-term patency and signal-enhancing properties of the stents.

Active stents (AMRIS) were implanted into the abdominal aorta in 7 chinchilla rabbits. MRI examinations were performed on a 1.5-T scanner for 6 months. Flow was measured proximal to, within, and distal to the stent. Precontrast and postcontrast MR angiography was performed (50 µmol Fe/kg VSOP C184). Flow curves were generated and signal-to-noise ratios (SNR) calculated. After 6 months DSA was performed and the rabbits were killed for stent explantation.

The stent remained patent over the study period and no stenoses or thrombi were observed. Flow measurements outside and inside the stent yielded similar flow profiles. Mean flow volume was 1.34 ml/s, 1.24 ml/s (n.s.), and 0.96 ml/s proximal to, within, and distal to the stent, respectively. The SNR at MRA was 14.89 before versus 2.6 after contrast medium administration. The postcontrast SNR was significantly higher within the stent than outside (28.8 versus 18.0, p0.05).

MRI flow measurements and imaging with signal enhancement inside an inductively coupled stent are possible. The long-term results show that signal enhancement is preserved and that no in-stent stenoses and thrombi occur.

Kivelitz, D, Klemmt, J, Wagner, S, Schnorr, J, Wetzler, R, Taupitz, M, Melzer, A, Hamm, B, et al, , Long-term Results with Active MRI Stents: Is the Signal-enhancing Effect Preserved?.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4417743.html