Taenia–tela choroidea complex and choroid plexus location help distinguish Dandy-Walker malformation and Blake pouch cysts

Background Dandy-Walker malformation and Blake pouch cysts can have overlapping imaging features. The choroid plexus and associated taenia–tela choroidea complex are displaced inferolaterally in Dandy-Walker malformation and below the vermis in Blake pouch cysts. Objective To determine the normal fetal and postnatal MR appearance of the choroid plexus and taenia–tela choroidea complex, and whether their location can help distinguish Dandy-Walker malformation from Blake pouch cysts. Materials and methods In this retrospective study, we evaluated brain MR exams from normal-appearing fetuses (gestational age 19–38 weeks) and infants, fetal and postnatal exams in Blake pouch cysts and Dandy-Walker malformation, and ambiguous cases equivocal for mild Dandy-Walker malformation and Blake pouch cysts. We documented choroid plexus and the taenia–tela choroidea complex location and axial and sagittal angles in each case. Then we contrasted and compared the original and updated fetal diagnoses based on taenia–tela choroidea complex and choroid plexus positions. Results The choroid plexus location and the taenia–tela choroidea complex location and angles varied significantly among normal exams, Blake pouch cyst exams and Dandy-Walker malformation exams ( P <0.01). Dandy-Walker malformation showed inferolateral displacement of the taenia–tela choroidea complex and choroid plexus distant from the vermis. Adding the taenia–tela choroidea complex and choroid plexus into the assessment improved diagnostic accuracy, especially in ambiguous cases. Conclusion The location of the taenia–tela choroidea complex and choroid plexus provided additional diagnostic neuroimaging clues that could be used in conjunction with other conventional findings to distinguish Dandy-Walker malformation and Blake pouch cysts. Normal, Blake pouch cyst, and Dandy-Walker malformation cases differed with regard to taenia–tela choroidea complex and choroid plexus position. Inferolateral taenia–tela choroidea complex displacement distant from the vermian margin was characteristic of Dandy-Walker malformation.