Improved Myocardial Tissue Characterization Using Delayed-Phase Dynamic Contrast-enhanced Cardiac MRI

Purpose To evaluate the performance of a delayed-phase dynamic contrast-enhanced (dDCE) MRI model in quantitative assessment of myocardial tissue physiology and late gadolinium enhancement (LGE) within 5 minutes after contrast material injection in reperfused myocardial infarction (MI). Materials and Methods This animal study included 11 canines (seven female) with reperfused MI. A dDCE model using dynamic postcontrast T1 maps was adopted to depict an unbiased contrast material washout process. The dDCE parameters derived from the 30-minute contrast material washout process (dDCE30min) and a 5-minute image subset (dDCE5min) were compared. LGE images were synthesized from the dDCE5min maps (LGEdDCE) and compared LGE extent and transmurality with the standard LGE images acquired at 15 minutes after contrast material injection (LGEstandard). Statistical analyses used paired tests for dependent group comparisons. Results The dDCE30min map demonstrated that extravascular extracellular volume and capillary permeability surface area product were higher in MI regions than in remote myocardium (61.12% ± 13.65 [SD] vs 13.43% ± 5.00; P = .02; 5.08 mL × g-1 × min-1 ± 4.10 vs 0.42 mL × g-1 × min-1 ± 0.55; P = .02, respectively). There was no evidence of differences between dDCE5min parameters and dDCE30min parameters (all P > .05). There was also no evidence of a difference between LGEdDCE and LGEstandard in LGE area (30.65% ± 11.94 vs 30.66% ± 11.94; P = .99) or transmurality (54.87% ± 15.57 vs 53.27% ± 15.98; P = .06), but LGEdDCE demonstrated a higher contrast-to-noise ratio (14.62 ± 13.03 vs 1.41 ± 0.97; P < .01). The area under the receiver operating characteristic curve of MI detection using LGEdDCE was 0.97 (95% CI: 0.94, >0.99), with 94.4% sensitivity and 96.7% specificity. Conclusion The developed dDCE MRI model for myocardial tissue assessment shows potential to enhance lesion contrast, quantify clinically relevant physiologic parameters, and support comprehensive evaluation of myocardial injury in heart disease. Keywords: Dynamic Contrast-enhanced MRI, Myocardial Infarction, MRI, Pharmacokinetics, Ischemic Heart Disease Supplemental material is available for this article.