title: Hyperemic stress myocardial perfusion cardiovascular magnetic resonance in mice at 3 Tesla: initial experience and validation against microspheres.
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).
  
  
  CONCLUSIONS
  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.
authors.forename: Roy
authors.initials: R
authors.lastname: Jogiya
authors.forename: Markus
authors.initials: M
authors.lastname: Makowski
authors.forename: Alkystsis
authors.initials: A
authors.lastname: Phinikaridou
authors.forename: Ashish S
authors.initials: AS
authors.lastname: Patel
authors.forename: Christian
authors.initials: C
authors.lastname: Jansen
authors.forename: Niloufar
authors.initials: N
authors.lastname: Zarinabad
authors.forename: Amedeo
authors.initials: A
authors.lastname: Chiribiri
authors.forename: Rene
authors.initials: R
authors.lastname: Botnar
authors.forename: Eike
authors.initials: E
authors.lastname: Nagel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kozerke
authors.forename: Sven
authors.initials: S
authors.lastname: Plein
mesh_terms: D000818:Animals; D002469:Cell Separation / Q000379:methods; D003287:Contrast Media; D003326:Coronary Circulation; D004176:Dipyridamole / Q000008:administration & dosage; D005240:Feasibility Studies; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000008:administration & dosage; D006940:Hyperemia / Q000503:physiopathology*; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging; D008297:Male; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D008863:Microspheres; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013997:Time Factors; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D003287:Contrast Media; D005456:Fluorescent Dyes; D009942:Organometallic Compounds; D014665:Vasodilator Agents; C090600:gadobutrol; D004176:Dipyridamole