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Ultrasound and Magnetic Resonance Imaging of Agenesis of the Corpus Callosum in Fetuses
Author(s) -
Ghassemi Neda,
Rupe Eric,
Perez Mishella,
LamaleSmith Leah,
Fratto Victoria M.,
Farid Nikdokht,
Hahn Michael,
Ramos Gladys A.,
Ho Yoona,
RakowPenner Rebecca,
Horton Katelyn,
Khan Sohini,
Jones Marilyn,
Pretorius Dolores H.
Publication year - 2020
Publication title -
journal of ultrasound in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 91
eISSN - 1550-9613
pISSN - 0278-4297
DOI - 10.1002/jum.15348
Subject(s) - medicine , corpus callosum , magnetic resonance imaging , agenesis of the corpus callosum , agenesis , fetus , corpus callosum agenesis , gestation , ultrasound , ventricle , lateral ventricles , anatomy , radiology , pregnancy , genetics , biology
Objectives We hypothesized that: (1) fetal frontal horn (FH) morphology and their proximity to the cavum septi pellucidi (CSP) can assist in suspecting complete agenesis of the corpus callosum (cACC) and partial agenesis of the corpus callosum (pACC) earlier than known indirect ultrasound (US) findings; (2) FHs assist in differentiating a true CSP from a pseudocavum; and (3) magnetic resonance imaging (MRI) is useful in learning FH morphology and pseudocavum etiology. Methods Thirty‐two patients with cACC and 9 with pACC were identified on an Institutional Review Board–approved retrospective review. Of the 41 cases, 40 had prenatal US, and 21 had prenatal MRI; 17 had follow‐up neonatal US, and 14 had follow‐up neonatal MRI. Variables evaluated retrospectively were the presence of a CSP or a pseudocavum, ventricle size and shape, and FH shape (comma, trident, parallel, golf club, enlarged, or fused). Displacement between the inferior edge of the FH and the midline or cavum/pseudocavum was measured. Results Fetal FHs had an abnormal shape in 77% ≤20 weeks' gestation, 86% ≤24 weeks, and 90% >24 weeks. Frontal horns were laterally displaced greater than 2 mm in 85% ≤20 weeks, 91% ≤24 weeks, and 95% >24 weeks. The CSP was absent in 100% of cACC cases and 78% of pACC cases, and a pseudocavum was present in 88% of cACC cases and 78% of pACC cases across gestation. Magnetic resonance imaging confirmed US pseudocavums to be focal interhemispheric fluid or an elevated/dilated third ventricle. Conclusions Frontal horns assist in assessing ACC ≤24 weeks and throughout gestation. Pseudocavums, often simulating CSPs, are common in ACC. Frontal horn lateral displacement and abnormal morphology, recognized by MRI correlations, are helpful in differentiating a pseudocavum from a true CSP. A normal CSP should not be cleared on screening US unless normally shaped FHs are seen directly adjacent to it.