Signal decay mapping of myocardial edema using dual-contrast fast spin-echo MRI

Purpose

To introduce a dual-contrast fast spin-echo (dcFSE) sequence for signal decay mapping of myocardial edema.

Materials and Methods

After consultation with the Institutional Review Board, 22 acute myocardial infarction (MI) patients were examined with magnetic resonance imaging (MRI) at 1.5T 2 days after revascularization. Edema was evaluated in 16 myocardial segments with an exponential fit for signal decay time (SDT) in dcFSE mapping and T₂ signal intensity ratio for single-contrast FSE. Myocardial viability was evaluated in late gadolinium enhancement (LGE). A control group of 10 volunteers was examined for edema imaging. SDT was compared in segment groups: 1) with LGE in MI, 2) penumbra, 3) remote from LGE, 4) controls. Groups 1/3 and 3/4 were tested on difference. Three phantoms providing similar T₂ but different T₁ relaxation times (low, intermediate, high) were examined with dcFSE and multicontrast spin echo sequence as a reference.

Results

The SDT/T₂ratio for segment groups was 1) 82msec/1.7 in segments with LGE; 2) 65msec/1.6 for penumbra, 3) 62msec/1.7 for remote segments, and 4) 50msec/1.6 in controls. In dcFSE group 1/3 (P < 0.0001) and in group 3/4 (P = 0.0002) SDT was significantly different. In single-contrast FSE the T₂ratio was not significantly different for both tests: 1/3 P = 0.1889; 3/4 P = 0.8879. T₂-overestimation of dcFSE was 23% in low, 29% in intermediate, and 35% in highly T₁ contaminated phantoms.

Conclusion

dcFSE signal decay edema mapping is feasible in volunteers and patients. DcFSE SDT is superior to T₂ratio for detection of high-grade and diffuse myocardial edema. J. Magn. Reson. Imaging 2015.

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