Quantitative assessment of magnetic resonance derived myocardial perfusion measurements using advanced techniques: microsphere validation in an explanted pig heart system.

Abstract

BACKGROUND:

Cardiovascular Magnetic Resonance (CMR) myocardial perfusion imaging has the potential to evolve into a method allowing full quantification of myocardial blood flow (MBF) in clinical routine. Multiple quantification pathways have been proposed. However at present it remains unclear which algorithm is the most accurate. An isolated perfused, magnetic resonance (MR) compatible pig heart model allows very accurate titration of MBF and in combination with high-resolution assessment of fluorescently-labeled microspheres represents a near optimal platform for validation. We sought to investigate which algorithm is most suited to quantify myocardial perfusion by CMR at 1.5 and 3 Tesla using state of the art CMR perfusion techniques and quantification algorithms.

METHODS:

First-pass perfusion CMR was performed in an MR compatible blood perfused pig heart model. We acquired perfusion images at physiological flow ("rest"), reduced flow ("ischaemia") and during adenosine-induced hyperaemia ("hyperaemia") as well as during coronary occlusion. Perfusion CMR was performed at 1.5 Tesla (n = 4 animals) and at 3 Tesla (n = 4 animals). Fluorescently-labeled microspheres and externally controlled coronary blood flow served as reference standards for comparison of different quantification strategies, namely Fermi function deconvolution (Fermi), autoregressive moving average modelling (ARMA), exponential basis deconvolution (Exponential) and B-spline basis deconvolution (B-spline).

RESULTS:

All CMR derived MBF estimates significantly correlated with microsphere results. The best correlation was achieved with Fermi function deconvolution both at 1.5 Tesla (r = 0.93, p < 0.001) and at 3 Tesla (r = 0.9, p < 0.001). Fermi correlated significantly better with the microspheres than all other methods at 3 Tesla (p < 0.002). B-spline performed worse than Fermi and Exponential at 1.5 Tesla and showed the weakest correlation to microspheres (r = 0.74, p < 0.001). All other comparisons were not significant. At 3 Tesla exponential deconvolution performed worst (r = 0.49, p < 0.001).

CONCLUSIONS:

CMR derived quantitative blood flow estimates correlate with true myocardial blood flow in a controlled animal model. Amongst the different techniques, Fermi function deconvolution was the most accurate technique at both field strengths. Perfusion CMR based on Fermi function deconvolution may therefore emerge as a useful clinical tool providing accurate quantitative blood flow assessment.

• Authors: Andreas Schuster, Niloufar Zarinabad, Masaki Ishida, Matthew Sinclair, Jeroen Phm van den Wijngaard, Geraint Morton, Gilion Ltf Hautvast, Boris Bigalke, Pepijn van Horssen, Nicolas Smith, Jos Ae Spaan, Maria Siebes, Amedeo Chiribiri, Eike Nagel
• Journal: Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance (J Cardiovasc Magn Reson) Vol. 16 Pg. 82 (Oct 14 2014) ISSN: 1532-429X [Electronic] England
• PMID: 25315438 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Validation Study)

Chemical References

• Contrast Media
• Fluorescent Dyes
• Organometallic Compounds
• gadobutrol

Topics

• Algorithms
• Animals
• Blood Flow Velocity
• Contrast Media
• Coronary Circulation
• Coronary Occlusion (diagnosis, physiopathology)
• Disease Models, Animal
• Fluorescent Dyes
• Hyperemia (diagnosis, physiopathology)
• Image Interpretation, Computer-Assisted
• In Vitro Techniques
• Magnetic Resonance Imaging (methods)
• Microbubbles
• Myocardial Ischemia (diagnosis, physiopathology)
• Myocardial Perfusion Imaging (methods)
• Organometallic Compounds
• Perfusion
• Predictive Value of Tests
• Reproducibility of Results
• Swine
• Time Factors