Optimization of bSSFP pulse sequence parameters for low-field fetal cardiac MRI at 0.55T

Motivation: Low field MRI at 0.55T offers advantages such as increased field homogeneities for fetal cardiac MRI and early diagnosis of congenital heart diseases (CHDs) but required careful optimization specific to the properties of low field. Goal(s): This study aimed to optimize the bSSFP sequence parameters at 0.55T to compensate for the reduced SNR and improve diagnostic capabilities in fetal cardiac MRI. Approach: Phantom experiments and in-utero studies were conducted to evaluate the impact of optimized parameters of bSSFP sequences on SNR, image quality, and clinical applicability. Results: The optimized bSSFP sequence parameters demonstrate increased SNR and good visualization of cardiac structures. Impact: The optimized bSSFP sequence at 0.55T has the potential to be used at low field strengths to prenatally diagnose congenital heart disease, thereby increasing accessibility for patients.