The fetal cerebellar vermis: assessment for abnormal development by ultrasonography and magnetic resonance imaging.
Fetal magnetic resonance provides a new tool in the imaging of the posterior fossa and is proving useful in cases that are difficult to assess sonographically by allowing further assessment of the fourth ventricle, cisterna magna, and vermian growth and development. We describe various criteria with which to evaluate vermian growth, including vermian biometry and the relationship between the superior and inferior lobes. We demonstrate 2 markers of normal vermian development: the primary fissure and fastigial point. We illustrate the tegmento-vermian angle, "closure" of the fourth ventricle, and communication of the fourth ventricle with the basal cisterns during development and in several disorders. We correlate those features with the expected embryological course of development and illustrate identification of these features and associated abnormalities of the posterior fossa, brain stem, and central nervous system in mid-trimester scans of fetuses with abnormal development. Correlation with contemporaneous ultrasound examinations is demonstrated.
Robinson
Ashley J
AJ
Department of Radiology, Children's Hospital of British Columbia, Vancouver V6H 3V4, Canada. ash@radiologist.net
Blaser
Susan
S
Toi
Ants
A
Chitayat
David
D
Halliday
William
W
Pantazi
Sophie
S
Gundogan
Munire
M
Laughlin
Suzanne
S
Ryan
Greg
G
D002531:Cerebellum / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D002946:Cisterna Magna / Q000002:abnormalities / Q000000981:diagnostic imaging; D003388:Cranial Fossa, Posterior / Q000002:abnormalities / Q000000981:diagnostic imaging; D005260:Female; D020546:Fourth Ventricle / Q000002:abnormalities / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D011247:Pregnancy; D016216:Ultrasonography, Prenatal