title: Heterogeneous microinfarcts caused by coronary microemboli: evaluation with multidetector CT and MR imaging in a swine model.
abstract: OBJECTIVE
  To directly compare the sensitivity of 64-section multidetector computed tomography (CT) with that of 1.5-T magnetic resonance (MR) imaging in the depiction and measurement of heterogeneous 7-8-week-old microinfarcts and the quantification of regional left ventricular (LV) function and perfusion in the territory of coronary intervention in a swine model.
  
  
  METHODS
  Approval was obtained from the institutional animal committee. An x-ray/MR system was used to catheterize the left anterior descending (LAD) coronary artery with x-ray guidance and to delineate the perfusion territory. The vessel was selectively microembolized in six pigs with small-diameter embolic material (40-120 microm, 250000 count). At 7-8 weeks after microembolization, multidetector CT and MR imaging were used to assess LV function, first-pass perfusion, and delayed contrast enhancement in remote myocardium and microinfarct scars. Histochemical staining with triphenyltetrazolium chloride (TTC) was used to confirm and quantify heterogeneous microinfarct scars. The two-tailed Wilcoxon signed rank test was used to detect differences between modalities and myocardial regions.
  
  
  RESULTS
  The LAD territory was 32.4% +/- 3.8(stadard error of the mean) of the LV mass. Multidetector CT and MR imaging have similar sensitivity in the detection of regional and global LV dysfunction and extent of microinfarct. The mean LV end-diastolic volume, end-systolic volume, and ejection fraction were 93 mL +/- 8, 46 mL +/- 4, and 50% +/- 3, respectively, on multidetector CT images and 92 mL +/- 8, 48 mL +/- 5, and 48% +/- 3, respectively, on MR images (P > or = .05). The extent of heterogeneous microinfarct was not significantly different between multidetector CT (6.3% +/- 0.8 of the LV mass), MR imaging (6.6% +/- 0.5 of the LV mass), and TTC staining (7.0% +/- 0.6 of the LV mass). First-pass multidetector CT and MR imaging demonstrated significant regional differences (P < .05) in time to peak between the heterogeneous microinfarct and remote myocardium (17.0 seconds +/- 0.3 and 12.4 seconds +/- 0.6, respectively, for multidetector CT and 17.2 seconds +/- 0.8 and 12.5 seconds +/- 1.0, respectively, for MR imaging).
  
  
  CONCLUSIONS
  Modern multidetector CT and MR imaging are sensitive modalities with which to depict heterogeneous microinfarcts and determine regional LV dysfunction and decreased perfusion in the territory of intervention. (c) RSNA, 2010.
authors.affiliation: Department of Radiology and Biomedical Imaging and Department of Pathology, University of California, San Francisco, 185 Berry St, Suite 350, Campus Box 0946, San Francisco, CA 94107-5705, USA.
authors.forename: Marcus
authors.initials: M
authors.lastname: Carlsson
authors.forename: David
authors.initials: D
authors.lastname: Saloner
authors.forename: Alastair J
authors.initials: AJ
authors.lastname: Martin
authors.forename: Philip C
authors.initials: PC
authors.lastname: Ursell
authors.forename: Maythem
authors.initials: M
authors.lastname: Saeed
mesh_terms: D000818:Animals; D002544:Cerebral Infarction / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology*; D003287:Contrast Media; D003328:Coronary Thrombosis / Q000150:complications* / Q000175:diagnosis*; D007090:Image Interpretation, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine; D008833:Microcirculation; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013552:Swine; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media