MR-based morphometry of the posterior fossa in fetuses with neural tube defects of the spine.
OBJECTIVE
In cases of "spina bifida," a detailed prenatal imaging assessment of the exact morphology of neural tube defects (NTD) is often limited. Due to the diverse clinical prognosis and prenatal treatment options, imaging parameters that support the prenatal differentiation between open and closed neural tube defects (ONTDs and CNTDs) are required. This fetal MR study aims to evaluate the clivus-supraocciput angle (CSA) and the maximum transverse diameter of the posterior fossa (TDPF) as morphometric parameters to aid in the reliable diagnosis of either ONTDs or CNTDs.


METHODS
The TDPF and the CSA of 238 fetuses (20-37 GW, mean: 28.36 GW) with a normal central nervous system, 44 with ONTDS, and 13 with CNTDs (18-37 GW, mean: 24.3 GW) were retrospectively measured using T2-weighted 1.5 Tesla MR -sequences.


RESULTS
Normal fetuses showed a significant increase in the TDPF (r = .956; p<.001) and CSA (r = .714; p<.001) with gestational age. In ONTDs the CSA was significantly smaller (p<.001) than in normal controls and CNTDs, whereas in CNTDs the CSA was not significantly smaller than in controls (p = .160). In both ONTDs and in CNTDs the TDPF was significantly different from controls (p<.001).


CONCLUSIONS
The skull base morphology in fetuses with ONTDs differs significantly from cases with CNTDs and normal controls. This is the first study to show that the CSA changes during gestation and that it is a reliable imaging biomarker to distinguish between ONTDs and CNTDs, independent of the morphology of the spinal defect.
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Ramona
R
Woitek
Public Hospital Wiener Neustadt, Wiener Neustadt, Austria.
Anton
A
Dvorak
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Michael
M
Weber
Department of Paediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.
Rainer
R
Seidl
Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria.
Dieter
D
Bettelheim
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Veronika
V
Schöpf
Department of Clinical Pathology, Medical University of Vienna, Vienna, Austria.
Gabriele
G
Amann
Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria.
Peter C
PC
Brugger
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Julia
J
Furtner
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Ulrika
U
Asenbaum
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Daniela
D
Prayer
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Gregor
G
Kasprian
D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D003937:Diagnosis, Differential; D005260:Female; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000295:instrumentation*; D012189:Retrospective Studies; D016137:Spina Bifida Cystica / Q000175:diagnosis* / Q000473:pathology; D016136:Spina Bifida Occulta / Q000175:diagnosis* / Q000473:pathology