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Assessment of myocardial viability with contrast-enhanced magnetic resonance imaging and comparison with single-photon emission computed tomography.

OBJECTIVE
To compare contrast-enhanced magnetic resonance imaging (ceMRI) with nuclear metabolic imaging for the assessment of myocardial viability in patients with chronic ischemic heart disease.


METHODS
Twenty patients with suspected chronic ischemic heart disease underwent ceMRI and technetium-99m sestamibi single-photon emission computed tomography (SPECT). Patients with positive SPECT results also underwent 18F-fluorodeoxyglucose (FDG) SPECT. In a 17-segment model, the segmental extent of hyperenhancement (SEH) by ceMRI was compared with segmental FDG and sestamibi uptake by SPECT. Correlation between the extent of hyperenhancement by ceMRI and left ventricular function was analyzed.


RESULTS
Seven patients got negative results both in ceMRI and technetium-99m sestamibi SPECT. The rest 13 patients with positive results then underwent 18F-FDG SPECT. In 221 segments of 13 patients, SEH was (2.1 +/- 8.2)%, (25.0 +/- 13.7)%, and (57.7 +/- 23.6)% in segments with normal metabolism/perfusion, metabolism/perfusion mismatch, and matched defects, respectively, and there were significant differences between either two of them (all P < 0.05). By receiver operating characteristic curve analysis, the area under the curve was 0.95 for the differentiation between viable and non-viable segments. At the cutoff value of 34%, SEH optimally differentiated viable from non-viable segments defined by SPECT. Using this threshold, the sensitivity and specificity of ceMRI to detect non-viable myocardium as defined by SPECT were 92% and 93%, respectively. Hyperenhancement size by ceMRI was correlated negatively with the left ventricular ejection fraction (r = - 0.90, P < 0.01) and positively with left ventricular volumes (r = 0.62 for end-diastolic volume, r = 0.75 for end-systolic volume, both P < 0.05).


CONCLUSION
CeMRI allows assessment of myocardial viability with a high accuracy in patients with chronic ischemic heart disease.