Modified DENSE MRI successfully measured myocardial strain and detected contrast-enhanced infarcted myocardium in mice, correlating well with conventional tag analysis (R = 0.90).
A modified DENSE MRI technique allows for simultaneous measurement of myocardial strain and detection of contrast-enhanced infarcted myocardium in mice.
Effect estimate: R = 0.90
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 T(1)-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 T(1)-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 T(1)-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 (E(cc)) and radial (E(rr)) strain were measured, and contrast-enhanced infarcted myocardium was detected by DENSE. At baseline, E(cc) was -0.16 +/- 0.01 and E(rr) was 0.39 +/- 0.07. After MI, E(cc) was 0.04 +/- 0.02 and E(rr) was 0.03 +/- 0.04 in infarcted regions, whereas E(cc) 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 E(cc) obtained by conventional tag analysis (R = 0.90).
Gilson et al. (2004) studied Myocardial infarction (n=9). Modified DENSE MRI vs. Conventional tag analysis was evaluated on Circumferential (E(cc)) and radial (E(rr)) strain (R = 0.90). Modified DENSE MRI successfully measured myocardial strain and detected contrast-enhanced infarcted myocardium in mice, correlating well with conventional tag analysis (R = 0.90).