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

Abstract

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. 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. 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). T2* cardiac MR imaging is more suitable than T2 cardiac MR imaging in the detection and characterization of acute reperfusion myocardial hemorrhage. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13122397/-/DC1.