Head-to-head comparison between contrast-enhanced magnetic resonance imaging and dobutamine magnetic resonance imaging in men with ischemic cardiomyopathy

Contrast-enhanced magnetic resonance imaging (MRI) can predict functional recovery after revascularization. Segments with small, subendocardial scars have a large likelihood of recovery, and segments with transmural infarction have a small likelihood of recovery. Segments with an intermediate extent of infarction have an intermediate likelihood of recovery, and therefore, additional information is needed. Accordingly, the transmurality of infarction on contrast-enhanced MRI was compared with low-dose dobutamine MRI to further define viability in 48 patients. Regional contractile dysfunction was determined by cine MRI at rest (17-segment model), and contractile reserve was determined using low-dose dobutamine infusion. Contrast-enhanced MRI was performed to assess the extent of scar tissue. A total of 338 segments (41%) were dysfunctional, with 61% having contractile reserve. Most segments (approximately 75%) with small, subendocardial scars (hyperenhancement scores 1 or 2) had contractile reserve, whereas contractile reserve was not frequently (17%) observed in segments with transmural infarction (hyperenhancement score 4) (p <0.05). Of segments with an intermediate infarct transmurality (hyperenhancement score 3), contractile reserve was observed in 42%, whereas 58% did not have contractile reserve. In conclusion, the agreement between contrast-enhanced MRI and low-dose dobutamine MRI is large in the extremes (subendocardial scars and transmural scars), and contrast-enhanced MRI may be sufficient to assess the likelihood of the recovery of function after revascularization. However, 61% of segments with an intermediate extent of scar tissue on MRI have contractile reserve and 39% lack contractile reserve. In these segments, low-dose dobutamine MRI may be needed to optimally differentiate myocardium with large and small likelihoods of functional recovery after revascularization.