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Hyperemic stress myocardial perfusion cardiovascular magnetic resonance in mice at 3 Tesla: initial experience and validation against microspheres.

Jogiya R, Makowski M, Phinikaridou A, Patel AS, Jansen C, Zarinabad N, Chiribiri A, Botnar R, Nagel E, Kozerke S, Plein S - J Cardiovasc Magn Reson (2013)

Bottom Line: There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84).Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis.Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Dynamic first pass contrast-enhanced myocardial perfusion is the standard CMR method for the estimation of myocardial blood flow (MBF) and MBF reserve in man, but it is challenging in rodents because of the high temporal and spatial resolution requirements. Hyperemic first pass myocardial perfusion CMR during vasodilator stress in mice has not been reported.

Methods: Five C57BL/6 J mice were scanned on a clinical 3.0 Tesla Achieva system (Philips Healthcare, Netherlands). Vasodilator stress was induced via a tail vein catheter with an injection of dipyridamole. Dynamic contrast-enhanced perfusion imaging (Gadobutrol 0.1 mmol/kg) was based on a saturation recovery spoiled gradient echo method with 10-fold k-space and time domain undersampling (k-t PCA). One week later the mice underwent repeat anaesthesia and LV injections of fluorescent microspheres at rest and at stress. Microspheres were analysed using confocal microscopy and fluorescence-activated cell sorting.

Results: Mean MBF at rest measured by Fermi-function constrained deconvolution was 4.1 ± 0.5 ml/g/min and increased to 9.6 ± 2.5 ml/g/min during dipyridamole stress (P = 0.005). The myocardial perfusion reserve was 2.4 ± 0.54. The mean count ratio of stress to rest microspheres was 2.4 ± 0.51 using confocal microscopy and 2.6 ± 0.46 using fluorescence. There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84).

Conclusion: First-pass myocardial stress perfusion CMR in a mouse model is feasible at 3 Tesla. Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis. Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies.

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Confocal microscopy images. a. confocal images at stress, b. confocal images at rest.
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Figure 4: Confocal microscopy images. a. confocal images at stress, b. confocal images at rest.

Mentions: In the midventricular slices matching the perfusion imaging, both fluorescent colored microspheres were identified using confocal laser microscopy (Figures 4a and b). The cumulative mean of microspheres injected at rest was 162 ± 32 and 397 ± 115 at stress (p = 0.0045) (Figure 5), with a mean count ratio of 2.4 ± 0.51. Using Pearson’s correlation, there was a strong association between MPR estimated by CMR and count ratio by confocal microscopy (R = 0.79) and no significant difference was observed. On Bland-Altman analysis, the mean bias between CMR and microscopy was −0.07 (95% limit of agreement −0.73 to 0.59) (Figure 6a).


Hyperemic stress myocardial perfusion cardiovascular magnetic resonance in mice at 3 Tesla: initial experience and validation against microspheres.

Jogiya R, Makowski M, Phinikaridou A, Patel AS, Jansen C, Zarinabad N, Chiribiri A, Botnar R, Nagel E, Kozerke S, Plein S - J Cardiovasc Magn Reson (2013)

Confocal microscopy images. a. confocal images at stress, b. confocal images at rest.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750232&req=5

Figure 4: Confocal microscopy images. a. confocal images at stress, b. confocal images at rest.
Mentions: In the midventricular slices matching the perfusion imaging, both fluorescent colored microspheres were identified using confocal laser microscopy (Figures 4a and b). The cumulative mean of microspheres injected at rest was 162 ± 32 and 397 ± 115 at stress (p = 0.0045) (Figure 5), with a mean count ratio of 2.4 ± 0.51. Using Pearson’s correlation, there was a strong association between MPR estimated by CMR and count ratio by confocal microscopy (R = 0.79) and no significant difference was observed. On Bland-Altman analysis, the mean bias between CMR and microscopy was −0.07 (95% limit of agreement −0.73 to 0.59) (Figure 6a).

Bottom Line: There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84).Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis.Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Dynamic first pass contrast-enhanced myocardial perfusion is the standard CMR method for the estimation of myocardial blood flow (MBF) and MBF reserve in man, but it is challenging in rodents because of the high temporal and spatial resolution requirements. Hyperemic first pass myocardial perfusion CMR during vasodilator stress in mice has not been reported.

Methods: Five C57BL/6 J mice were scanned on a clinical 3.0 Tesla Achieva system (Philips Healthcare, Netherlands). Vasodilator stress was induced via a tail vein catheter with an injection of dipyridamole. Dynamic contrast-enhanced perfusion imaging (Gadobutrol 0.1 mmol/kg) was based on a saturation recovery spoiled gradient echo method with 10-fold k-space and time domain undersampling (k-t PCA). One week later the mice underwent repeat anaesthesia and LV injections of fluorescent microspheres at rest and at stress. Microspheres were analysed using confocal microscopy and fluorescence-activated cell sorting.

Results: Mean MBF at rest measured by Fermi-function constrained deconvolution was 4.1 ± 0.5 ml/g/min and increased to 9.6 ± 2.5 ml/g/min during dipyridamole stress (P = 0.005). The myocardial perfusion reserve was 2.4 ± 0.54. The mean count ratio of stress to rest microspheres was 2.4 ± 0.51 using confocal microscopy and 2.6 ± 0.46 using fluorescence. There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84).

Conclusion: First-pass myocardial stress perfusion CMR in a mouse model is feasible at 3 Tesla. Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis. Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies.

Show MeSH
Related in: MedlinePlus