title: First-pass perfusion CMR two days after infarction predicts severity of functional impairment six weeks later in the rat heart.
abstract: BACKGROUND
  In humans, dynamic contrast CMR of the first pass of a bolus infusion of Gadolinium-based contrast agent has become a standard technique to identify under-perfused regions of the heart and can accurately demonstrate the severity of myocardial infarction. Despite the clinical importance of this method, it has rarely been applied in small animal models of cardiac disease. In order to identify perfusion delays in the infarcted rat heart, here we present a method in which a T1 weighted MR image has been acquired during each cardiac cycle.
  
  
  RESULTS
  In isolated perfused rat hearts, contrast agent infusion gave uniform signal enhancement throughout the myocardium. Occlusion of the left anterior descending coronary artery significantly reduced the rate of signal enhancement in anterior regions of the heart, demonstrating that the first-pass method was sensitive to perfusion deficits. In vivo measurements of myocardial morphology, function, perfusion and viability were made at 2 and 8 days after infarction. Morphology and function were further assessed using cine-MRI at 42 days. The perfusion delay was larger in rat hearts that went on to develop greater functional impairment, demonstrating that first-pass CMR can be used as an early indicator of infarct severity. First-pass CMR at 2 and 8 days following infarction better predicted outcome than cardiac ejection fraction, end diastolic volume or end systolic volume.
  
  
  CONCLUSIONS
  First-pass CMR provides a predictive measure of the severity of myocardial impairment caused by infarction in a rodent model of heart failure.
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, UK. daniel.stuckey1@imperial.ac.uk
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Stuckey
authors.forename: Carolyn A
authors.initials: CA
authors.lastname: Carr
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Meader
authors.forename: Damian J
authors.initials: DJ
authors.lastname: Tyler
authors.forename: Mark A
authors.initials: MA
authors.lastname: Cole
authors.forename: Kieran
authors.initials: K
authors.lastname: Clarke
mesh_terms: D000818:Animals; D003287:Contrast Media; D004195:Disease Models, Animal; D005260:Female; D019786:Gadolinium DTPA; D006333:Heart Failure / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D019028:Magnetic Resonance Imaging, Cine; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009206:Myocardium / Q000473:pathology*; D010477:Perfusion; D011237:Predictive Value of Tests; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function; D012720:Severity of Illness Index; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA