3-Tesla MRI for the evaluation of myocardial viability: a comparative study with 1.5-Tesla MRI

Purpose. We compared 3-Tesla Q-T) and 1.5-Tesla (1.5-T) cardiac magnetic resonance imaging (MRI) for the assessment of myocardial viability in nearly identical experimental conditions. Materials and methods. Thirty-five patients (mean age 63 +/- 11; 94.2% men) submitted to primary coronary angioplasty underwent both 3-T and 1.5-T cardiac MRI, which was considered the gold standard. Comparison was performed on the basis of the same viability imaging protocol, which included resting cine-MR [balanced fast-field echo (b-FFE) sequence] followed by contrast-enhanced MR to evaluate perfusion and delayed enhancement (DE). We then performed functional index measurements and visual estimation of kinesis, perfusion and DE referring to a 5-point scale. Image quality was assessed on the basis of signal to noise ratio (SNR) and contrast to noise ratio (CNR). Results. We found nonsignificant differences between the two scanners (p=NS) in measuring the functional and viability parameters. Myocardial SNR was significantly higher with 3-T MRI compared with 1.5-T MRI (61.3% gain). Even though a loss of CNR was recorded in b-FFE and in first-pass perfusion sequences (12.4% and 23.7%, respectively), on DE images, we quantified the increase of SNR and CNR of infarction of 387.8% and 330%, respectively. Conclusions. We found that 3-T MRI showed high concordance with 1.5-T MRI in the evaluation of functional and viability parameters and provided better evidence of damaged myocardium.