Dual energy CT with nonlinear image blending improves visualization of delayed myocardial contrast enhancement in acute myocardial infarction.

OBJECTIVES

The objective of this study was to evaluate the effect of, and optimal parameters for, nonlinear image blending compared with linear image blending in the late-phase dual energy computed tomography (DECT) for the visualization of delayed myocardial contrast enhancement in acute myocardial infarction (MI).

MATERIALS AND METHODS

Acute reperfused MI was induced in 7 pigs by temporary occlusion of the left anterior descending or the left circumflex artery. Two hours after the reperfusion, a contrast-enhanced, late-phase DECT (80 kV/140 kV) scanning was performed. The DECT data were postprocessed with linear and nonlinear image blending techniques. Contrast and percentage signal differences between healthy and infarcted myocardium as well as the blood pool of the left ventricle were computed for the linear and nonlinear techniques and the low- and high-kilovolt images. Data were compared using repeated-measures analysis of variance and post hoc t tests.

RESULTS

The nonlinear blending showed the highest signal differences for all contrasts and analyses. Repeated-measures ANOVA results confirmed that the differences were statistically significant for the different postprocessing techniques (P value ranging from <0.001-0.003). Paired-samples post hoc t tests proved the significance of these results (P value ranging from <0.001-0.037). The ideal settings for the nonlinear image blending can thus be deduced from the computed tomographic values of the regions of interest in the linearly blended images with the weighting factor 0.3.

CONCLUSIONS

Nonlinear image blending improves the visualization of acute MI in the late-phase DECT. It is superior to linearly blended images and source images obtained at 80 or 140 kV.