Fetal Posterior Fossa Fluid Collections

Fetal Posterior Fossa Fluid Collections

Sorting Out Posterior Fossa
Fluid Collections Ma#hew Whitehead, MD Assistant Professor, Neuroradiology Director, Pediatric Neuroradiology Educa<on Children’s Na<onal Medical Center Washington, DC Disclosures 2 NORMAL 27 Weeks Learning Objectives 1. To review normal embryologic development of the cerebellum, meninges, and meningeal spaces to help improve understanding of posterior fossa fluid collections 2. To introduce a pattern approach for diagnosis of posterior fossa fluid collections 4 Introduction • 
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Posterior fossa fluid collections are challenging! Etiologies : normal variation vs. pathologic cystic, ventricular, and meningeal fluid spaces Imaging patterns characteristic: -­‐Dandy-­‐Walker -­‐Blake pouch cyst -­‐enlarged (“mega”) cisterna magna -­‐arachnoid cyst Differential diagnosis considered within framework of developmental posterior fossa anatomy Embryology 6 Cerebellum: Coming of age Rhombic lips CB union (51d) Meninx transforms Cerebellum extra-­‐ventricular Torcular posiJoned 1st Trimester 2nd Trimester Neuronal migraJon Magendie 3rd Trimester 5 – 10 weeks Blake Pouch Cyst 36 Weeks Cerebellum: Coming of age PonJne flexure Cerebellum Rhombic lips extraventricular CB union (51d) Meninx transforms Luschka? 1st Trimester 2nd Trimester Neuronal migraJon Cerebellum formed Magendie 3rd Trimester By 18 Weeks 1.  Fastigial point 2.  Primary fissure 3.  Covered 4th ventricle roof Physiologic delay up to 24 weeks Cysts u Definitive classification requires histologic evaluation of wall -­‐Arachnoid: arachnoid -­‐Blake pouch: arachnoid, ependyma, glia, choroid plexus -­‐DW: arachnoid, ependyma, glia, neurons u Cyst type can generally be gathered based on location and MR appearance 12 Differential Diagnosis 1.  Cysts: 2. Cyst mimics: a. Arachnoid duplication a. normal development b. Blake Pouch cyst b. Dandy-­‐Walker c. Enlarged “Mega” cisterna magna c. Joubert d. Fibrous arachnoid (d. Cephalocele) (e. Epidermoid) (e. Cerebellar hypoplasia) ( f. Enteric) ( f. Occipital meningeal space) (g. Vascular malformation) Arachnoid Cyst 24 weeks Arachnoid Cyst 24 weeks Enlarging Arachnoid cyst, Hydrocephalus 14 months postnatal Liliequist Membrane Arachnoid Cyst 27 eeks GA 2 dw
ays Liliequist Membrane Differential Diagnosis 1.  Cysts: 2. Cyst mimics: a. Arachnoid duplication a. normal development b. Blake Pouch cyst b. Dandy-­‐Walker c. Enlarged “Mega” cisterna magna c. Joubert d. Fibrous arachnoid (d. Cephalocele) (e. Epidermoid) (e. Cerebellar hypoplasia) ( f. Enteric) ( f. Occipital meningeal space) (g. Vascular malformation) Blake Pouch Cyst 27 Weeks Blake Pouch Cyst Blake Pouch Cyst -­‐Incomplete regression of PMA and malformation of foramen of Magendie -­‐OR failed perforation of Luschka Imaging: •  Choroid plexus extends into cyst wall •  Aperture dilated •  Mass effect •  Variable enlargement of posterior fossa •  +/-­‐Minor vermian malrotation Differential Diagnosis 1.  Cysts: 2. Cyst mimics: a. Arachnoid duplication a. normal development b. Blake Pouch cyst b. Dandy-­‐Walker c. Enlarged “Mega” cisterna magna c. Joubert d. Fibrous arachnoid (d. Cephalocele) (e. Epidermoid) (e. Cerebellar hypoplasia) ( f. Enteric) ( f. Occipital meningeal space) (g. Vascular malformation) 29 Weeks Enlarged “Mega” Cisterna Magna Differential Diagnosis 1.  Cysts: 2. Cyst mimics: a. Arachnoid duplication a. normal development b. Blake Pouch cyst b. Dandy-­‐Walker c. Enlarged “Mega” cisterna magna c. Joubert d. Fibrous arachnoid (d. Cephalocele) (e. Epidermoid) (e. Cerebellar hypoplasia) ( f. Enteric) ( f. Occipital meningeal space) (g. Vascular malformation) Hemorrhage, adhesions, and hydrocephalus 30 Weeks Differential Diagnosis 1.  Cysts: 2. Cyst mimics: a. Arachnoid duplication a. normal development b. Blake Pouch cyst b. Dandy-­‐Walker c. Enlarged “Mega” cisterna magna c. Joubert d. Fibrous arachnoid (d. Cephalocele) (e. Epidermoid) (e. Cerebellar hypoplasia) ( f. Enteric) ( f. Occipital meningeal space) (g. Vascular malformation) Dandy-­‐Walker Spectrum Dandy-­‐Walker Continuum 22 weeks Differential Diagnosis 1.  Cysts: 2. Cyst mimics: a. Arachnoid duplication a. normal development b. Blake Pouch cyst b. Dandy-­‐Walker c. Enlarged “Mega” cisterna magna c. Joubert d. Fibrous arachnoid (d. Cephalocele) (e. Epidermoid) (e. Cerebellar hypoplasia) ( f. Enteric) ( f. Occipital meningeal space) (g. Vascular malformation) Joubert Syndrome Joubert Syndrome (Oro-­‐facial-­‐digital syndrome VI) 19 weeks DWM & related disorders normal Cerebellum vermis dysplasJc hemispheres apposed HypoplasJc/malrotated vermis hemispheres splayed no MCM choroid éaperture +/-­‐hydro BPC no DWC torcular inversion DWM MTM Joubert Conclusion u  Cystic posterior fossa lesions are common u  Most benign and able to be classified by location u  Brain deserves special scrutiny References 1. Wong AM, et al. Prenatal MR imaging of Dandy-­‐Walker complex: midline sagittal area analysis. Eur J Radiol 2012; 81(1):e26-­‐30 2. Saleem SN, et al. Role of MR imaging in prenatal diagnosis of pregnancies at risk for Joubert syndrome and related disorders. AJNR Am J Neuroradiol 2010;31(3):424-­‐9 3. Vatansever D, et al. Multidimensional analysis of fetal posterior fossa in health and disease. Cerebellum 2013;12(5):632-­‐44 4. Chen SC, et al. Fetal posterior fossa volume: assessment with MR imaging. Radiology 2006;238(3):997-­‐1003 5. Glenn OA. MR imaging of the fetal brain Pediatr Radiol 2010;40(1):68-­‐81 6. Herman-­‐Sucharska I, et al. Fetal central nervous system malformations on MR images. Brain Dev 2009;31(3):185-­‐99 7. Raybaud C, et al. MR imaging of fetal brain malformations. Childs Nerv Sys 2013; 19(7-­‐8):455-­‐470 8. Bekker MN, et al. The role of magnetic resonance imaging in prenatal diagnosis of fetal anomalies. Eur J Gynecol Reprod Biol 2001;96(2):173-­‐8 9. Gandolfi et al. Prenatal diagnosis and outcome of fetal posterior fossa fluid collections. Ultrasound Obstet Gynecol 2012; 39(6):625-­‐31 10. Epelman M, et al. Differential Diagnosis of Intracranial Cystic Lesions at Head US: Correlation with CT and MR Imaging. Radiographics 11. Elmadbouh H, et al. 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Rosa RF, et al. Trisomy 18 and neural tube defects. Pediatr Neurol 2013;49(3):203-­‐4 19. Poretti et al. Delineation and diagnostic criteria of oral-­‐facial-­‐digital syndrome Type IV. Orphanet Journal of Rare Diseases 2012; 7:4:1-­‐14 Thanks! Email: [email protected]