Evaluation of malformations of the fetal central nervous system using fetal MRI

Objective: Ultrasound as the primary prenatal screening modality is used to detect fetal anomalies. Aim of the study was to prove the additional value of fetal magnetic resonance imaging (MRI).

Methods: In 25 pregnant women (age 30.6 +/- 4.8; 24 single and one twin pregnancy) with pathologic findings of the central nervous system detected by obstetric ultrasound, a fetal MRI was performed. All sequences (T2w-HASTE, TRUEFISP, T 1w-FLASH 2D, DWI) were performed using the breath-hold technique. The results were compared to postnatal MRI or ultrasound scan findings and tested for correlation with the clinical course and development of these children.

Results: Three to seven days after ultrasound, an MRI of all 26 fetuses without sedation was performed (26.6 +/- 4.0 GW). One healthy twin was not included in this study. MRI confirmed the ultrasonographic diagnosis in 7 cases. Compared to ultrasound, an additional pathology could be detected by MRI in 8 cases. In 10 cases ultrasound diagnosis was overruled by MRI. Prenatal MRI findings were confirmed by postnatal imaging in 18 children. The clinical course was predictable in 8 of 15 cases, depending on the pathology detected. Three newborns died in the perinatal period.

Conclusions: Our results showed that fetal MRI has a high impact as an addition to ultrasound in evaluating congenital CNS pathology. Fetal MRI has become a helpful device for advising parents. However, clinical course and development still cannot be predicted based on MRI findings alone.