Abstract 11265: Progression of Myocardial Edema and Hemorrhage using T2, T2*, and Diastolic Wall Thickness Post Acute Myocardial Infarction at Multiple Time Points
Background: Enhanced T2 combined with consideration of T2* and diastolic wall thickness (DWT) may facilitate interpretation of potentially complex patterns of myocardial damage and tissue response infarction zones. Our goal was to demonstrate myocardial edema using T2 spiral and DWT, and myocardial hemorrhage using T2* in patients post acute MI.
Methods: Patients were enrolled post acute MI (creatine kinase >500 IU/L) and underwent CMR on a GE Signa Excite, 1.5T scanner with a 8-channel receive coil at 48 hours, 3 weeks and 6 months. T2 maps were computed from a cardiac-gated spiral imaging sequence with T2 preparations yielding TEs=2.9,24.3,88.2,184.2 ms to assess myocardial edema. The T2* sequence was a multiecho acquisition with 8 echoes (between 1.4 and 12.7ms) acquired at TR=14.6ms. DHE was also performed.
Results: 36 patients were enrolled. At 48 hours, the mean T2 (59 ms vs 40 ms) and mean DWT (11 mm vs 7 mm) were higher (P<0.001) and mean T2* (24 ms vs 38 ms) was lower (p<0.001) in the infarct segment (IS) compared to a remote segment (RS). Figure 1 shows the evolution of T2 and T2* behavior over time. At 48 hours, panel-A demonstrates an increased T2 in the IS relative to RS. However, there is myocardial hemorrhage on T2*-weighted images (panel-B) along with microvascular obstruction (panel-C). The difference in DWT between IS and RS was 3.3 mm. At 3 weeks, the T2 in the IS increased further relative to RS (panel-D). At this time, there is evidence of less hemorrhage (panel-E), less microvascular obstruction (panel-F) and a reduced difference in DWT of 0.7 mm between IS and RS. At 6 months, there is a normalized T2 and T2* along with myocardial thinning in the IS (panel-G-I).
Conclusions: If myocardial hemorrhage is present, then early scans are affected by the competing effects of T2*, counteracting an increased T2 signal. This may be important in accurately quantifying area at risk and identifying those patients most likely to suffer deleterious left ventricular remodeling.
- © 2010 by American Heart Association, Inc.