磁振造影對心肌存活之評估：與多保他命超音波心圖及鉈-201斷層造影之比較

Chronic coronary artery disease (CAD) is the leading cause of congestive heart
failure and cardiac mortality. Functional recovery depends on accurate identification
of reversible, viable myocardium. We evaluated the value of contrast-enhanced
magnetic resonance imaging (MRI) in the assessment of myocardial viability. The study population consisted of 14 patients with angiographically significant
CAD (≧70% diameter stenosis) and left ventricular (LV) dysfunction. Each patient
underwent simultaneous dobutamine stress echocardiography (DSE), thallium-201
( 201 Tl) SPECT, contrast-enhanced MRI and coronary angiography within one month.
MRI and 201 Tl images were semiquantitatively interpreted using a 17-segment model.
For 201 Tl SPECT, segment with a severe (≦50% of peak uptake), fixed perfusion
defect was considered as scar. In gadolinium-enhanced MRI, hyperenhacement score
≧ 2 was defined as nonviability. The amount of viable tissue in MRI correlated
positively with 201 Tl uptake and DSE (p ＜0.0001, each). The concordance rate of
MRI and 201 Tl SPECT in detecting myocardial viability was 74.4%. Complete
agreement of the 3 tests was 65.5%. In conclusion, there is a good correlation between
the amount of viable tissue on MRI and 201 Tl uptake and also between these and
contractile reserve detected by DSE. However, further study of a larger number of
patients with revascularization is needed to explore which modality is superior in
predicting functional recovery after intervention.