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

Abstract

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% 6 13 (standard deviation) lower in patients (15.9 msec 6 4.5 vs 35.2 msec 6 2.1, P , .001) and 40% 6 10 lower in canines (23.0 msec 6 4.0 vs 39.3 msec 6 2.5, P , .001). Mean T2* of nonhemorrhagic infarctions was marginally elevated by 6% 6 2.5 (37.8 msec 6 2.5, P = .021) in patients and by 8% 6 5 (44.6 msec 6 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% 6 19, P , .001; nonhemorrhagic: 78% 6 27, P , .001) and in canines (hemorrhagic: 42% 6 22, P , .001; nonhemorrhagic: 65% 6 22, P , .001). Consistent with STIR SI findings, mean T2 of both hemorrhagic (62.0 msec 6 4.9) and nonhemorrhagic (71.7 msec 6 7.3) infarctions in canines was elevated relative to mean T2 of remote myocardium (52.1 msec 6 4.8) by 18% 6 9 and 38% 6 13, respectively (P , .001 for both). Conclusion

Effect of Infarct Severity on Regional and Global Left Ventricular Remodeling in Patients with Successfully Reperfused ST Segment Elevation Myocardial Infarction

“…Second, we used dark-blood T2-weighted fast spin-echo sequences to assess IMH. Other study findings suggested that T2*-weighted sequences may be more sensitive in detecting IMH than T2-weighted sequences (27,28). Third, although we found LV remodeling to be related to infarct severity, this was not associated with increased mortality at 4-month follow-up.…”

Intramyocardial haemorrhage after acute myocardial infarction

“…The presence of intramyocardial haemorrhage in angiographically successfully primary PCI for STEMI is associated with large infarct size, as reflected by high cardiac enzyme levels. 11,13,14,[87][88][89] Moreover, intramyocardial haemorrhage results in worse cardiac function, independent of infarct size, as shown by greater left ventricular end diastolic and systolic volumes and lower ejection fractions than in patients without intramyocardial haemorrhage. Ultimately, therefore, intramyocardial haemorrhage is related to poor clinical outcomes and death (Table 1).…”

Risk stratification by cardiac magnetic resonance imaging after ST-elevation myocardial infarction

“…2). To date, most studies have used T2-weighted images to identify IMH, but T2 Ã -weighted techniques seem to be even more accurate and sensitive [51]. Therefore, further clinical validation to define the most accurate sequence is still necessary.…”