Figure 6

Longitudinal evaluation of progressive changes from infarcted myocardium to large LM (arrows) by in vivo, ex vivo cMRI and histological study. Serial images of the midcardiac slice by T1WI (A1-D1), T2WI (A2-D2), DE-MRI (A3-D3) and Cine-MRI (A4-D4 and A5-D5) were taken at 48 hours (A1-A5), 2 weeks (B1-B5), 2 months (C1-C5) and 9 months (D1-D5), respectively. Acute (48 hours) MI (A1-A5): The infarct appeared isointense on T1WI (A1); hyperintense including papillary muscle on T2WI (A2); hyperenhanced on DE-cMRI (A3); and isointense but hypokinetic on Cine-MRI (A4, A5). Early (2 weeks) chronic MI (B1-B5): The infarct remained isointense on T1WI (B1); hyperintense but smaller on T2WI (B2); hyperenhanced transmural on DE-MRI, thinner than before (B3); and dyskinesia of the lateral wall on Cine-MRI (B4, B5). Chronic (2 months) MI (C1-C5): slightly hypointense on T1WI (C1); almost isointense with irregular, boundary on T2WI (C2); moderately enhanced on DE-MRI (C3); partially signal lost on the fat suppression Cine-MRI, suggesting the initiation of LM (C4, C5). Healed (9 months) MI (D1-D5): hyperintense with clear boundary on T1WI (D1); moderately hyperintense on T2WI (D2); lack of contrast enhancement on DE-MRI (D3); and signal void on cine-MRI with fat suppression (D4, D5). Postmortem T1WI and T2WI MRI with fat suppression (E1, E2): drastic signal losses corresponded to the high signal on in vivo T1WI and T2WI (D1, D2), suggesting large LM. Macroscopies (F1: fresh section; F2: 15 min after TTC staining; F3: 24 hours after TTC staining) corresponded well with MR images. Fat extensively occupied TTC-negative region. Histology (G1-G4): MTC stained photograph (G1) and photomicrograph (G2) (magnification, ×100) and H&E stained photograph (G3) and photomicrograph (G4) (magnification, ×100) demonstrated clearly LM, with high densities of the adipose cells surrounded by few fibers and macrophages. Dashed square indicates where microscopy was focused.