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Differentiating Closed Versus Open Spinal Dysraphisms on Fetal MRI
Usha D Nagaraj1, Karin S Bierbrauer1, Jose L Peiro1
11 Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229-3026.
Objective:
The purpose of this study is to identify differences in findings between open and closed spinal dysraphisms seen on fetal MR images.
Materials And Methods:
A single-institution retrospective analysis of fetal MR images for spinal dysraphism was performed. Postnatal images and clinical and operative reports were reviewed.
Results:
Sixteen fetuses with postnatally confirmed closed spinal dysraphisms were included. Of these, 25% (4/16) had posterior fossa anomalies, 12.5% (2/16) had ventriculomegaly, and 37.5% (6/16) had OEIS (omphalocele, exstrophy, imperforate anus, and spinal defects) complex. Of 90 fetuses with postnatally confirmed open spinal dysraphism, 95.6% (86/90) had posterior fossa anomalies, 85.6% (77/90) had ventriculomegaly, and none had OEIS complex. Twenty fetuses with open spinal dysraphism were randomly selected to compare with fetuses with closed spinal dysraphisms. Continuity of the epidermal and subcutaneous tissues with the sac wall on fetal MR images was seen in 93.8% (15/16) of patients with closed spinal dysraphisms, as opposed to 5% (1/20) of patients with open spinal dysraphisms. The mean (± SD) sac wall thickness was less in open (0.7 ± 0.6 mm) than closed (2.9 ± 1.3 mm; p < 0.001) spinal dysraphism. None of the fetuses had T1-hyperintense fat within the defect.
Conclusion:
On fetal MR images, closed spinal dysraphisms tend to have a sac wall in continuity with the epidermal and subcutaneous tissues, a thicker sac wall, fewer posterior fossa anomalies, and high association with OEIS complex.
Insights
Fetal MRI reveals key differences between open and closed spinal dysraphisms. Closed types show a continuous sac wall and thicker walls, while open types have more posterior fossa anomalies and ventriculomegaly.
Area of Science:
- Medical Imaging
- Developmental Biology
- Pediatric Surgery
Background:
- Spinal dysraphisms are congenital abnormalities affecting spinal cord development.
- Accurate prenatal diagnosis is crucial for management and outcomes.
- Fetal Magnetic Resonance (MR) imaging offers detailed anatomical visualization.
Purpose of the Study:
- To delineate distinguishing features of open versus closed spinal dysraphisms on fetal MR imaging.
- To compare imaging findings to guide prenatal diagnosis and counseling.
Main Methods:
- Retrospective analysis of fetal MR images for spinal dysraphisms.
- Correlation with postnatal imaging, clinical, and operative reports.
- Comparison of imaging characteristics between open and closed types.
Main Results:
- Closed spinal dysraphisms (n=16) frequently showed a continuous epidermal/subcutaneous sac wall (93.8%) and thicker sac walls (2.9 ± 1.3 mm).
- Open spinal dysraphisms (n=90) demonstrated higher rates of posterior fossa anomalies (95.6%) and ventriculomegaly (85.6%).
- OEIS complex was associated with closed spinal dysraphisms (37.5%), but not open types.
Conclusions:
- Fetal MR imaging can differentiate open and closed spinal dysraphisms based on sac wall characteristics and associated anomalies.
- Closed spinal dysraphisms present with a thicker, continuous sac wall and are linked to OEIS complex.
- Open spinal dysraphisms are more commonly associated with posterior fossa anomalies and ventriculomegaly.
