Prenatal assessment of the cardiovascular structure and brain development of fetuses with tetralogy of Fallot on fetal MRI / 中华放射学杂志

ABSTRACT

Objective:To explore the value of prenatal MRI in assessing the cardiovascular structure and brain development of fetuses with tetralogy of Fallot (TOF).Methods:From August 2011 to April 2021, 30 fetuses of TOF with gestational age (GA) 18-33 (25±3) weeks were retrospectively enrolled in Shanghai Children′s Medical Center, School of Medicine, Shanghai Jiao Tong University. Sixty normal fetuses were selected with matched GA of TOF fetuses as control group. In 30 fetuses with TOF, the GA of 17 fetuses were less than 25 weeks and of 13 fetuses were more than 25 weeks. The balanced fast field echo sequence MRI was performed to measure the diameter of the aortic arch isthmus (AoI), the main pulmonary artery (MPA) and the ratio was calculated (MPA/AoI). The size of ventricular septal defect (VSD) was measured in TOF group. The single-shot turbo spin echo sequence MRI was performed to measure fetal brain biparietal diameter (BBD), brain frontal-occipital length (BFOL), skull biparietal diameter (SBD), skull fronto-occipital diameter (SOD) and head circumference (HC). The Pearson analysis was used to evaluate the correlation of the above indicators with GA. The independent sample t test was used to compare the differences in various indicators between TOF and control groups in both GA≤25 and GA>25 weeks. Results:The sizes of VSD in TOF fetuses were (3.5±1.1) mm (GA≤25 weeks) and (4.4±0.6) mm (GA>25 weeks). The AoI, MPA, BBD, BFOL, SBD, SOD, HC were positively associated with GA (TOF group r=0.80, 0.50, 0.92, 0.93, 0.91, 0.84, 0.91, MPA P=0.005, others all P<0.001; control group r=0.90, 0.87, 0.96, 0.95, 0.93, 0.95, 0.96, all P<0.001). For fetuses with GA≤25 weeks, there were 17 fetuses in TOF group and 34 fetuses in control group, and the AoI in TOF group was larger than that in control group ( t=10.00, P<0.001), the MPA, MPA/AoI, BFOL were smaller than those in control group (all P<0.05). No statistical significant differences of BBD, SBD, SOD, HC were found between the groups (all P>0.05), For fetuses with GA>25, there were 13 fetuses in TOF group and 26 fetuses in control group, and the AoI in TOF group was larger than that in control group ( t=3.36, P=0.002) and MPA, MPA/AoI, BBD, BFOL, SOD, HC were smaller than those in control group (all P<0.05). No statistically significant difference of SBD was found between groups ( P=0.068). Conclusions:MRI is feasible to measure the cardiovascular structure and the brain development of fetuses with TOF. Fetuses with TOF have varying degrees of VSD, MPA stenosis and AoI dilation. An altered brain growth of fetuses with TOF appears in the second trimester of pregnancy.