title: Magnetic resonance imaging characterization of circumferential and longitudinal strain under various coronary interventions in swine.
abstract: OBJECTIVE
  To compare the acute changes in circumferential and longitudinal strain after exposing a coronary artery to various interventions in swine.
  
  
  METHODS
  Percutaneous balloon angioplasty catheter was guided to location aid device (LAD) under X-ray fluoroscopy to create different patterns of ischemic insults. Pigs (n = 32) were equally divided into 4 groups: controls, 90 min LAD occlusion/reperfusion, LAD microembolization, and combined LAD occlusion/microembolization/reperfusion. Three days after interventions, cine, tagged and viability magnetic resonance imaging (MRI) were acquired to measure and compare left and right circumferential strain, longitudinal strain and myocardial viability, respectively. Measurements were obtained using HARP and semi-automated threshold method and statistically analyzed using unpaired t-test. Myocardial and vascular damage was characterized microscopically.
  
  
  RESULTS
  Coronary microemboli caused greater impairment in l left ventricular (LV) circumferential strain and dyssynchrony than LAD occlusion/reperfusion despite the significant difference in the extent of myocardial damage. Microemboli also caused significant decrease in peak systolic strain rate of remote myocardium and LV dyssynchrony. Cine MRI demonstrated the interaction between LV and right ventricular (RV) at 3 d after interventions. Compensatory increase in RV free wall longitudinal strain was seen in response to all interventions. Viability MRI, histochemical staining and microscopy revealed different patterns of myocardial damage and microvascular obstruction.
  
  
  CONCLUSIONS
  Cine MRI revealed subtle changes in LV strain caused by various ischemic insults. It also demonstrated the interaction between the right and left ventricles after coronary interventions. Coronary microemboli with and without acute myocardial infarction (AMI) cause complex myocardial injury and ventricular dysfunction that is not replicated in solely AMI.
authors.affiliation: Mohammed SA Suhail, Mark W Wilson, Steven W Hetts, Maythem Saeed, Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, CA 94107-5705, United States.
authors.forename: Mohammed Sa
authors.initials: MS
authors.lastname: Suhail
authors.affiliation: Mohammed SA Suhail, Mark W Wilson, Steven W Hetts, Maythem Saeed, Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, CA 94107-5705, United States.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Wilson
authors.affiliation: Mohammed SA Suhail, Mark W Wilson, Steven W Hetts, Maythem Saeed, Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, CA 94107-5705, United States.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Hetts
authors.affiliation: Mohammed SA Suhail, Mark W Wilson, Steven W Hetts, Maythem Saeed, Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, CA 94107-5705, United States.
authors.forename: Maythem
authors.initials: M
authors.lastname: Saeed
keywords: Acute myocardial infarct; Magnetic resonance imaging; Microembolization; Myocardial strain; Percutaneous coronary interventions