Usage of the T1 effect of an iron oxide contrast agent in an animal model to quantify myocardial blood flow by MRI

Lüdemann, Lutz; Schmitt, Boris; Podrabsky, Petr; Schnackenburg, Bernhard; Böck, Johannes; Gutberlet, Matthias

doi:10.1016/j.ejrad.2006.12.002

« Previous Next »European Journal of Radiology
Volume 62, Issue 2 , Pages 247-256, May 2007

Usage of the T₁ effect of an iron oxide contrast agent in an animal model to quantify myocardial blood flow by MRI

Lutz Lüdemann
- Department of Radiology and Nuclear Medicine Charité—Universitätmedizin Berlin, Campus Virchow-Klinikum, Germany
- They contributed equally to this work.
- Corresponding author at: Charité, Campus Virchow-Klinikum, Berlin, Strahlenklinik, Augustenburger Platz 1, 13353 Berlin, Germany. Tel.: +49 30 450557188; fax: +49 30 450557979.
Boris Schmitt
- Department of Congenital Heart Disease, Deutsches Herzzentrum, Berlin, Germany
- They contributed equally to this work.
Petr Podrabsky
- Department of Radiology and Nuclear Medicine Charité—Universitätmedizin Berlin, Campus Virchow-Klinikum, Germany
Bernhard Schnackenburg
- Philips Medical Systems, Hamburg, Germany
Johannes Böck
- Department of Radiology and Nuclear Medicine Charité—Universitätmedizin Berlin, Campus Virchow-Klinikum, Germany
Matthias Gutberlet
- Department of Radiology and Nuclear Medicine Charité—Universitätmedizin Berlin, Campus Virchow-Klinikum, Germany

Received 28 July 2006; received in revised form 30 November 2006; accepted 1 December 2006.

Abstract

Background

To present a new method for fully quantitative analysis of myocardial blood flow (MBF) using magnetic resonance imaging. The first pass of an intravascular iron oxide contrast medium can be used to quantify myocardial perfusion. The technique was validated in an animal model using colored microspheres.

Materials and methods

In six pigs, a tracking catheter was positioned in the left anterior descending artery (LAD). Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed on a 1.5-T scanner using a hybrid gradient-echo/echoplanar imaging (GRE-EPI) sequence. Regional myocardial blood flow (rMBF) was altered by either inducing vasodilatation with adenosine or creating coronary artery obstruction. The T₁ effect of a superparamagnetic iron oxide-based contrast medium (Resovist^®) administered at a dose of 8μmol/kg was used. Upslope, time-to-peak and peak intensity were calculated from the signal intensity–time curves and absolute rMBF using the Kety–Schmidt equation; results were compared to those obtained using colored microspheres.

Results

The mean rMBF calculated by MRI was 1.49 (±6.91, quartile width) ml/min/g versus 3.21 (±1.61) ml/min/g measured by means of microspheres under resting conditions. rMBF increased to a mean of 6.21 (±2.83) ml/min/g versus 4.22 (±1.70) ml/min/g under adenosine and was reduced to zero flow in total occlusion. Linear regression showed the best correlation for upslope (R=0.714), time-to-peak (R=0.626) and the Kety–Schmidt equation (R=0.584).

Conclusions

The T₁ effect of an iron oxide-based contrast medium allows determination of rMBF when using the Kety–Schmidt equation. The results are similar to those obtained with the standard of reference, colored micropheres, but not better than the results of the semiquantitative approach.

Keywords: Magnetic resonance imaging, Perfusion, Blood flow, Blood volume, Contrast media