Prenatal assessment of cerebellar vermian lobulation: fetal MRI with 3‐Tesla postmortem validation

Abstract

Fetal vermian lobulation can be assessed accurately and reliably after 22 weeks on precise midsagittal sequences with 1.5-T T2-weighted MRI. Fetal vermian lobules show non-uniform growth, with expansion of DFT and culmen at the expense of the other vermian lobules. Evaluation and elucidation of vermian lobulation in normal fetuses should enable better characterization of fetuses with hindbrain malformations. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Quantitative fetal magnetic resonance imaging assessment of cystic posterior fossa malformations

“…Recent advances in fetal imaging and, specifically, fetal MRI, allow for accurate and reliable delineation of the vermian lobules 11 . Characterization and quantification of vermian structures are relevant for the diagnosis of morphologically different subgroups of cPFM, as these subgroups may explain the well-known heterogeneity in the neurodevelopmental outcomes of affected cases.…”

“…For the definition of cerebellar lobules and fissures, the nomenclature proposed by Schmahmann et al 20 was used as an anatomical reference. The cerebellar vermis consists of nine separable lobules 21 , but in the present study the maximum number of differentiable lobules was taken to be seven ( Figure 2), because the three lobules of the posterior lobe (the DFT) could not be differentiated in any brain-normal fetal cases in a prior study 11 . We determined in how many cases the DFT could be differentiated into two or three lobules.…”

“…As a reference standard, age-matched fetuses with normal structural brain development on ultrasound and MRI from an existing database were included 11 . Indications for MRI in this group were mainly body malformations and premature rupture of membranes.…”

“…In this study, BV angle was measured between the posterior border of the brainstem at the level of the pons and the tangent of the ventral vermis ( Figure 1). The number of vermian lobules was assessed in accordance with a previous study in brain-normal controls 11 . For the definition of cerebellar lobules and fissures, the nomenclature proposed by Schmahmann et al 20 was used as an anatomical reference.…”

“…cPFM are usually identified by prenatal ultrasound screening, however, a definitive diagnosis of a malformation may be difficult. Owing to the absence of acoustic shadowing, fetal magnetic resonance imaging (MRI) allows consistent and dedicated assessment of the cerebellum and even its small structures, such as the vermian lobules 11 . The morphology of the cerebellar vermis and in particular the number of vermian lobules have been linked to neurodevelopmental outcome 12 .…”