Purpose: To investigate myocardial infarction (MI), late gadolinium (Gd) enhancement (LGE), cardiovascular magnetic resonance imaging (CMRI) is used as the current gold standard for the in vivo diagnosis in patients and preclinical studies. While inversion recovery (IR) fast gradient echo LGE imaging is the preferred technique at clinical field strengths it remains to be investigated which is the best sequence at higher field strength. We therefore compared the IR technique against cine fast low shot angle (cine-FLASH) for the quantification of MI size in mice at 7T in vivo.
Materials and methods: Five mice were used to optimize cine-FLASH and IR parameters. Nine mice were subsequently imaged with optimized parameters using both techniques 2-3 days after MI and ≈30 minutes post Gd injection.
Results: The difference in infarct size values was within 3.3% between the two CMRI techniques and within 7.5% of histological values by Bland-Altman analysis. Contrast-to-noise-ratio between infarcted and normal tissue as well as blood was higher for cine-FLASH with the additional benefit of a 2-time-fold shorter scan time than with the IR method. Furthermore, left ventricular function/volumes could be calculated from cine-FLASH images before as well as after Gd injection.
Conclusion: In conclusion, cine-FLASH LGE MRI represents an attractive alternative to IR LGE MRI for infarct size assessment in mice at high field strengths because it provides similar accuracy while being more robust, faster, and less user dependent.