Refining the Neuroimaging Definition of the Dandy-Walker Phenotype

Area of Science:

• Neuroimaging
• Pediatric Neurology
• Developmental Biology

Background:

• Dandy-Walker malformation (DWM) is a spectrum of posterior fossa abnormalities with variable clinical outcomes.
• Traditional diagnostic criteria for DWM lack precision, necessitating updated imaging standards based on cerebellar development.

Purpose of the Study:

• To establish updated, objective imaging criteria for Dandy-Walker malformation (DWM).
• To differentiate DWM from vermian hypoplasia using specific quantitative measures of the posterior fossa and cerebellum.

Main Methods:

• Retrospective analysis of 446 fetal and pediatric MR imaging examinations.
• Re-evaluation using choroid plexus/tela choroidea location and fastigial recess shape.
• Comparison of multiple posterior fossa and cerebellar measurements between DWM and non-DWM groups.

Main Results:

• Quantitative measures, particularly the tegmentovermian and fastigial recess angles, significantly differentiated DWM from other diagnoses pre- and postnatally (P < .01).
• Posterior fossa perimeter and vascular injury evidence were not significant differentiators (P > .3).
• Postnatal imaging showed differentiation using superior posterior fossa angle, torcular location, and vermian height (P < .01).

Conclusions:

• The modern Dandy-Walker malformation (DWM) phenotype is characterized by inferior vermian hypoplasia, enlarged tegmentovermian angle, displaced tela choroidea/choroid plexus, obtuse fastigial recess, and unpaired caudal lobule.
• Posterior fossa size and torcular location should be excluded from diagnostic criteria.
• Refined imaging criteria will aid future research into DWM etiologies and clinical outcomes.