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

Iron-Sensitive Cardiac Magnetic Resonance Imaging for Prediction of Ventricular Arrhythmia Risk in Patients With Chronic Myocardial Infarction

“…Infarct volume and gray-zone volume were measured from the LGE images using Mean+5SD 33 and Mean+2-3SD 39 criteria respectively relative to a reference ROI placed in the remote myocardium. Iron volume was measured from the T 2 *-weighted image acquired at TE=6.5ms using the Mean-2SD criterion relative to the reference ROI 40, 41 . For a given canine, T 2 * value of the iron deposition detected within each slice of T 2 *-weighted image was measured, and whole-heart mean T 2 * value was obtained by averaging across all the slices.…”

Cardiovascular Magnetic Resonance in Acute ST-Segment–Elevation Myocardial Infarction

“…Of the two approaches, T2*-mapping has been shown to have greater sensitivity for detecting intramyocardial hemorrhage following STEMI when compared to T2-mapping (Table 1). 4041 …”

Effect of Microvascular Obstruction and Intramyocardial Hemorrhage by CMR on LV Remodeling and Outcomes After Myocardial Infarction

“…IMH detected by both T2 (41,42) and T2* images has been correlated with the presence of hemorrhage on histopathologic analysis (kappa 0.96, p < 0.01) (43–45) (Figures 3 and 4). A recent study (46) in 14 patients with STEMI and 20 canines with acute reperfused MI suggests that T2* may be more suitable than T2 imaging techniques for assessing myocardial hemorrhage. The T2* decreased on average 54% in hemorrhagic infarctions and was 6% higher in nonhemorrhagic infarctions compared with remote myocardium.…”