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

PURPOSE: We compared 3-Tesla (3-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.