Detection of Acute Reperfusion Myocardial Hemorrhage with Cardiac MR Imaging: T2 versus T2*

Purpose: To evaluate T2 and T2* changes in acute reperfused hemorrhagic and nonhemorrhagic myocardial infarctions and to determine which technique is more suitable in the detection of intramyocardial hemorrhage at 1.5 T. Materials and Methods: Patient studies were approved by the institutional review board and were HIPAA compliant. Patients (n = 14, three women) with first ST-elevation myocardial infarction underwent cardiac magnetic resonance (MR) imaging 3 days after angioplasty. T2* maps, T2 short inversion time inversion-recovery (STIR) images, and late gadolinium enhancement (LGE) images were acquired. Animal studies were approved by the institutional animal care and use committee. Canines (n = 20) were subjected to ischemia-reperfusion injury, and cardiac MR imaging was performed 5 days after reperfusion. T2* and T2 maps and T2 STIR and LGE images were acquired. Repeated-measures analysis of variance or the Friedman test was used to compare T2 and T2* changes in patients with hemorrhagic infarctions and those with nonhemorrhagic infarctions. Results: Relative to remote myocardium, mean T2* of hemorrhagic infarctions was 54% +/- 13 (standard deviation) lower in patients (15.9 msec +/- 4.5 vs 35.2 msec +/- 2.1, P < .001) and 40% +/- 10 lower in canines (23.0 msec +/- 4.0 vs 39.3 msec +/- 2.5, P < .001). Mean T2* of nonhemorrhagic infarctions was marginally elevated by 6% +/- 2.5 (37.8 msec +/- 2.5, P = .021) in patients and by 8% +/- 5 (44.6 msec +/- 4.8, P = .012) in canines. In contrast, mean T2 STIR signal intensity (SI) of both hemorrhagic infarctions and nonhemorrhagic infarctions was higher than that in remote myocardium both in patients (hemorrhagic: 37% +/- 19, P < .001; nonhemorrhagic: 78% +/- 27, P < .001) and in canines (hemorrhagic: 42% +/- 22, P < .001; nonhemorrhagic: 65% +/- 22, P < .001). Consistent with STIR SI findings, mean T2 of both hemorrhagic (62.0 msec +/- 4.9) and nonhemorrhagic (71.7 msec +/- 7.3) infarctions in canines was elevated relative to mean T2 of remote myocardium (52.1 msec +/- 4.8) by 18% +/- 9 and 38% +/- 13, respectively (P < .001 for both). Conclusion: T2* cardiac MR imaging is more suitable than T2 cardiac MR imaging in the detection and characterization of acute reperfusion myocardial hemorrhage. (C) RSNA, 2013