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

Schuster A, Zarinabad N, Ishida M, Sinclair M, van den Wijngaard JP, Morton G, Hautvast GL, Bigalke B, van Horssen P, Smith N, Spaan JA, Siebes M, Chiribiri A, Nagel E - J Cardiovasc Magn Reson (2014)

Bottom Line: All CMR derived MBF estimates significantly correlated with microsphere results.Fermi correlated significantly better with the microspheres than all other methods at 3 Tesla (p < 0.002).All other comparisons were not significant.

View Article: PubMed Central - PubMed

Affiliation: Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK. andreas_schuster@gmx.net.

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.

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Related in: MedlinePlus

Agreement of quantitative perfusion analysis using different algorithms with the reference-standard of microsphere derived quantitative perfusion at 1.5 Tesla. The top row shows the correlation of CMR derived quantitative perfusion analysis using different algorithms with the reference-standard of microsphere derived quantitative perfusion (Microspheres MBF). The bottom row shows the agreement between CMR derived perfusion and Microspheres MBF using the Bland Altman analysis. There was good correlation with minimal error between CMR derived quantitative perfusion analysis and microspheres, which was most evident for Fermi function deconvolution (left hand side).
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Fig3: Agreement of quantitative perfusion analysis using different algorithms with the reference-standard of microsphere derived quantitative perfusion at 1.5 Tesla. The top row shows the correlation of CMR derived quantitative perfusion analysis using different algorithms with the reference-standard of microsphere derived quantitative perfusion (Microspheres MBF). The bottom row shows the agreement between CMR derived perfusion and Microspheres MBF using the Bland Altman analysis. There was good correlation with minimal error between CMR derived quantitative perfusion analysis and microspheres, which was most evident for Fermi function deconvolution (left hand side).

Mentions: All the explanted hearts recovered electrical function upon reperfusion. In case of reperfusion arrhythmias, defibrillation was performed to achieve sinus rhythm. Hearts were shocked for 3 ± 2 times on average. All hearts remained reasonably stable throughout the perfusion experiments. Heart Rate was 71 ± 15. The heart weight was 272 ± 19 g. The external roller pump blood flow was set to 238 ± 46 mL/min. Further measurements were taken during reduced flow at 118 ± 20 mL/min and during adenosine induced hyperemia with 392 ± 47 mL/min. These flow rates constituted an overall LV perfusion of 0.89 ± 0.18, 0.45 ± 0.1 and 1.47 ± 0.16 mL/min/g LV, respectively. On a segmental level, perfusion estimates derived from the different techniques based on CMR SI-time curves were compared to those obtained with microspheres. Figure 3 shows the relation between segmental microsphere and CMR derived perfusion for 1.5 Tesla and Figure 4 for 3 Tesla.Figure 3


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

Schuster A, Zarinabad N, Ishida M, Sinclair M, van den Wijngaard JP, Morton G, Hautvast GL, Bigalke B, van Horssen P, Smith N, Spaan JA, Siebes M, Chiribiri A, Nagel E - J Cardiovasc Magn Reson (2014)

Agreement of quantitative perfusion analysis using different algorithms with the reference-standard of microsphere derived quantitative perfusion at 1.5 Tesla. The top row shows the correlation of CMR derived quantitative perfusion analysis using different algorithms with the reference-standard of microsphere derived quantitative perfusion (Microspheres MBF). The bottom row shows the agreement between CMR derived perfusion and Microspheres MBF using the Bland Altman analysis. There was good correlation with minimal error between CMR derived quantitative perfusion analysis and microspheres, which was most evident for Fermi function deconvolution (left hand side).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4195947&req=5

Fig3: Agreement of quantitative perfusion analysis using different algorithms with the reference-standard of microsphere derived quantitative perfusion at 1.5 Tesla. The top row shows the correlation of CMR derived quantitative perfusion analysis using different algorithms with the reference-standard of microsphere derived quantitative perfusion (Microspheres MBF). The bottom row shows the agreement between CMR derived perfusion and Microspheres MBF using the Bland Altman analysis. There was good correlation with minimal error between CMR derived quantitative perfusion analysis and microspheres, which was most evident for Fermi function deconvolution (left hand side).
Mentions: All the explanted hearts recovered electrical function upon reperfusion. In case of reperfusion arrhythmias, defibrillation was performed to achieve sinus rhythm. Hearts were shocked for 3 ± 2 times on average. All hearts remained reasonably stable throughout the perfusion experiments. Heart Rate was 71 ± 15. The heart weight was 272 ± 19 g. The external roller pump blood flow was set to 238 ± 46 mL/min. Further measurements were taken during reduced flow at 118 ± 20 mL/min and during adenosine induced hyperemia with 392 ± 47 mL/min. These flow rates constituted an overall LV perfusion of 0.89 ± 0.18, 0.45 ± 0.1 and 1.47 ± 0.16 mL/min/g LV, respectively. On a segmental level, perfusion estimates derived from the different techniques based on CMR SI-time curves were compared to those obtained with microspheres. Figure 3 shows the relation between segmental microsphere and CMR derived perfusion for 1.5 Tesla and Figure 4 for 3 Tesla.Figure 3

Bottom Line: All CMR derived MBF estimates significantly correlated with microsphere results.Fermi correlated significantly better with the microspheres than all other methods at 3 Tesla (p < 0.002).All other comparisons were not significant.

View Article: PubMed Central - PubMed

Affiliation: Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK. andreas_schuster@gmx.net.

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.

Show MeSH
Related in: MedlinePlus