MRI is emerging as an important modality for assessing myocardial function in transgenic and knockout mouse models of cardiovascular disease, including myocardial infarction (MI). Displacement encoding with stimulated echoes (DENSE) measures myocardial motion at high spatial resolution using phase-reconstructed images. The current DENSE technique uses inversion recovery (IR) to suppress T1-relaxation artifacts; however, IR is ill-suited for contrast-enhanced infarct imaging in the heart, where multiple T 1 values are observed. We have developed a modified DENSE method employing complementary acquisitions for T1-independent artifact suppression. With this technique, displacement and strain are measured in phase-reconstructed images, and contrast-enhanced regions of infarction are depicted in perfectly coregistered magnitude-reconstructed images. The displacement measurements and T1-weighted image contrast were validated with the use of a rotating phantom. Modified DENSE was performed in mice (N = 9) before and after MI. Circumferential (Ecc) and radial (Err) strain were measured, and contrast-enhanced infarcted myocardium was detected by DENSE. At baseline, Ecc was -0.16 ± 0.01 and Err was 0.39 ± 0.07. After MI, E cc was 0.04 ± 0.02 and Err was 0.03 ± 0.04 in infarcted regions, whereas Ecc was -0.12 ± 0.02 and E rr was 0.38 ± 0.09 in noninfarcted regions. In vivo E cc as determined by DENSE correlated well with Ecc obtained by conventional tag analysis (R = 0.90).
- Contrast-enhanced MRI
- Myocardial infarction
- Myocardial strain
- Myocardial tagging
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology