Fetal brain biometry in isolated mega cisterna magna: MRI and US study

Abstract

Objective

To characterize the biometric parameters in ultrasound and brain MRI of fetuses with isolated mega cisterna magna (MCM).

Methods

Cross-sectional historical cohort study conducted at a single tertiary medical center between 2011 and 2018. All fetuses underwent US and brain MRI scans. Matching analysis was performed according to gender and gestational age.

Results

The study included a total of 103 fetuses; 44 fetuses with isolated MCM in the study group, and a control group of 59 fetuses with normal CNS. The study group had larger biparietal diameter (BPD) (86 vs. 79.8 mm, p = .001) and head circumference (HC) (318 vs. 292 mm, p < .001) on ultrasound. On MRI, study group had larger occipitofrontal diameter (OFD) (99 vs. 92 mm, p < .001) and BPD (77 vs. 72 mm, p < .001). Male fetuses’ prevalence was higher in the study group (77.3% vs. 47.5%). After matching 20 fetuses from each group, the study group had larger HC (310.1 versus 300.7 mm, p = .029) and OFD (113.4 versus 108.3 mm, p = .009) on ultrasound, and larger OFD (97.4 versus 94.6, p = .013) on brain MRI.

Conclusions

Isolated MCM may be related to other large fetal CNS biometric measurements in both ultrasound and MRI and might be influenced by fetal gender.

Keywords:

• Cisterna magna;
• fetus;
• ultrasonography;
• magnetic resonance imaging;
• central nervous system

Acknowledgments

None.

Disclosure statement

No potential conflict of interest was reported by the author(s).