USPIO-enhanced direct MR imaging of thrombus: preclinical evaluation in rabbits.

Abstract

PURPOSE:

To test the hypothesis that ultrasmall superparamagnetic iron oxide (USPIO) particles may diffuse into nonendothelialized fresh thrombi and thus allow for direct magnetic resonance (MR) imaging of a thrombus.

MATERIALS AND METHODS:

Stagnation thrombi of different thrombus ages (1, 3, 5, 7, and 9 days) were induced in the external jugular veins of 25 rabbits. Direct MR imaging of thrombi was performed by using a fat-saturated T1-weighted gradient-echo sequence (three-dimensional [3D] magnetization prepared rapid acquisition gradient echo) before and 24 hours after intravenous administration of USPIO (particle size, 25 nm; 200 micromol per kilogram of body weight). Thrombus length on 3D reconstruction images was compared with that depicted on a radiographic venogram and with histologic findings (joint reference standard). In addition, T2*-weighted gradient-echo images were acquired and scored semiquantitatively.

RESULTS:

The hyperintensity of the thrombus segment depicted on T1-weighted images (thrombus length determined with 3D reconstruction images divided by true thrombus length) increased significantly after administration of contrast medium at a thrombus age of 3 days (0.6 +/- 0.4 [SD] to 0.8 +/- 0.4; P =.02), 5 days (0.1 +/- 0.1 to 1.0 +/- 0.1; P <.001), and 7 days (0 to 0.6 +/- 0.4; P =.02), but not at an age of 1 and 9 days. No significant change in the thrombus signal intensity was observed on T2*-weighted images.

CONCLUSION:

The animal model showed that direct MR imaging of the thrombus improved 24 hours after USPIO administration with a T1-weighted sequence. No improvement was seen with the T2*-weighted sequence.

• Authors: S A Schmitz, S Winterhalter, S Schiffler, R Gust, S Wagner, M Kresse, S E Coupland, W Semmler, K J Wolf
• Journal: Radiology (Radiology) Vol. 221 Issue 1 Pg. 237-43 (Oct 2001) ISSN: 0033-8419 [Print] United States
• PMID: 11568346 (Publication Type: Journal Article)

Chemical References

• Contrast Media
• Dextrans
• Magnetite Nanoparticles
• Oxides
• ferumoxtran-10
• Iron
• Ferrosoferric Oxide

Topics

• Animals
• Contrast Media
• Dextrans
• Disease Models, Animal
• Female
• Ferrosoferric Oxide
• Iron
• Magnetic Resonance Imaging (methods)
• Magnetite Nanoparticles
• Male
• Oxides
• Phlebography
• Rabbits
• Thrombosis (pathology)