title: Three-dimensional MRI assessments of patchy and large myocardial infarction in beating and nonbeating swine hearts: validation with microscopy.
abstract: OBJECTIVE
  To measure and validate patchy and large myocardial infarction (MI) at 3 days and 5 weeks in beating and nonbeating hearts using contrast-enhanced three-dimensional (3D) inversion-recovery gradient echo (IR-GRE) magnetic resonance imaging (MRI) and microscopy.
  
  
  METHODS
  Pigs (n = 28) were subjected to 1) patchy MI (group I), 2) large MI (group II), or 3) combined (patchy and large) MI (groups III and IV) using microemboli and/or 90-minute left anterior descending (LAD) occlusion and imaged at 3 days and 5 weeks after interventions. Gadolinium diethylenetriamine penta-acetic acid (Gd-DTPA)-enhanced 3D and two-dimensional (2D) IR-GRE were performed for comparison in beating and nonbeating hearts. Macroscopic histochemical and microscopic histopathologic measurements were used for validation.
  
  
  RESULTS
  Three-dimensional images demonstrated hyperenhanced patchy microinfarction, large MI, hypoenhanced/hyperenhanced microvascular obstruction, and infarct resorption. Acute and chronic combined MI on 3D was underestimated compared to microscopy (bias: -1.8 ± 3.8%) but overestimated acute large infarction. In beating and nonbeating hearts, close correlations/agreements were found between 3D/2D acquisitions in all groups (beating hearts: r = 0.70-0.99; bias: group I 0.47 ± 2.0%, II 0.33 ± 1.2%, III 0.54 ± 1.5%, and IV 0.28 ± 1.0%).
  
  
  CONCLUSIONS
  The 3D IR-GRE underestimated the extent of acute and chronic combined MI compared to microscopic measurements. This sequence may have the potential to differentiate patchy from large MI and demonstrate MI healing after coronary interventions.
authors.affiliation: Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, 185 Berry St, Suite 350, Campus Box 0946, San Francisco, CA 94107-5705.
authors.forename: Robert
authors.initials: R
authors.lastname: Jablonowski
authors.affiliation: Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, 185 Berry St, Suite 350, Campus Box 0946, San Francisco, CA 94107-5705.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Wilson
authors.affiliation: Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, 185 Berry St, Suite 350, Campus Box 0946, San Francisco, CA 94107-5705.
authors.forename: Noor
authors.initials: N
authors.lastname: Joudi
authors.affiliation: Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, 185 Berry St, Suite 350, Campus Box 0946, San Francisco, CA 94107-5705.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Hetts
authors.affiliation: Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, 185 Berry St, Suite 350, Campus Box 0946, San Francisco, CA 94107-5705. Electronic address: maythem.saeed@ucsf.edu.
authors.forename: Maythem
authors.initials: M
authors.lastname: Saeed
mesh_terms: D000465:Algorithms; D000818:Animals; D003287:Contrast Media; D019786:Gadolinium DTPA; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009203:Myocardial Infarction / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013552:Swine
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: Magnetic resonance imaging; acute myocardial infarct; animal studies; microscopy; patchy infarct