Increased myocardial wall thickening as index of viability assessment: a preliminary report on delayed contrast MRI.

PURPOSE: Regional wall thickening measurement by delayed contrast MRI may assess myocardial viability and functional recovery of ischemic cardiomyopathy.

MATERIALS AND METHODS: Delayed contrast MRI data was used in 40 patients with significant coronary artery disease and severe left ventricular dysfunction. Regional wall thickening on follow-up MRI served as an index of functional recovery in patients receiving revascularization. For comparison, myocardial viability was assessed by MRI and 201Tl SPECT in 10 patients using a 17-segment method.

RESULTS: On 480 segments, MRI hyperintensities showed positive correlation with 201Tl reduction (r = 0.71, p < 0.0001) in the inferior wall and apex. Delayed MRI detected myocardial viability better than 201Tl SPECT. Delayed contrast-enhanced MRI showed diagnostic accuracy 65%, sensitivity 95%, specificity 25%, positive predictive value 65% and negative predictive value 75%, whereas 201Tl SPECT showed diagnostic accuracy 54%, sensitivity 72%, specificity 25%, positive predictive value 52% and negative predictive value 54%. Areas under the ROC curves by MRI and 201Tl SPECT were 0.59 +/- 0.04, 0.52 +/- 0.05, respectively (p = 0.07). The viability concordance was 80% between 201Tl SPECT and MRI.

CONCLUSION: Delayed contrast-enhanced MRI may detect the inferior wall thickening and apex as an index of viable myocardium better than 201Tl SPECT. Myocardial viability may predict functional recovery after revascularization in ischemic cardiomyopathy.