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Establishment of normative values for the fetal posterior fossa by magnetic resonance imaging
Author(s) -
Chapman Teresa,
Menashe Sarah J.,
Zare Megan,
Alessio Adam M.,
Ishak Gisele E.
Publication year - 2018
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.5367
Subject(s) - magnetic resonance imaging , posterior fossa , sagittal plane , medicine , posterior cranial fossa , gestational age , perimeter , fetus , anatomy , nuclear medicine , radiology , pregnancy , mathematics , geometry , biology , genetics
Objective Suspected Dandy‐Walker continuum anomalies constitute a significant percentage of prenatal cases evaluated by magnetic resonance imaging (MRI). To unify the description of posterior fossa malformations, we sought to establish objective measurements for the posterior fossa in normal fetuses between 18 and 37 weeks gestation. Methods T2‐weighted images of normal fetal brains in sagittal projection were obtained from fetal magnetic resonance (MR) studies of normal brains performed from 2009 to 2017.121 fetal brains were included in the analysis. Three radiologists reviewed images and recorded the following for each case: superior posterior fossa angle (SPFA), posterior fossa perimeter, and tegmento‐vermian angle (TVA). Results For each feature, the mean of the measurements, the percentage of absolute difference of the reader measurement compared with mean measurement, and the interclass correlation (ICC) were calculated. Values are reported as mean ± standard deviation. Perimeter increases linearly with age, whereas the SPFA and the TVA are independent of gestational age. For all included cases, the SPFA averaged 100.9° ± 8° and the TVA averaged 2.5° ± 2.3°. Conclusion The superior posterior fossa angle, a novel measurement, and the posterior fossa perimeter can be used for establishing the expected size of the posterior fossa in second‐ and third‐trimester fetuses by MRI.