Pediatric Radiology

, Volume 35, Issue 2, pp 124–140 | Cite as

MRI of the fetal posterior fossa

  • Catherine Adamsbaum
  • Marie Laure Moutard
  • Christine André
  • Valérie Merzoug
  • Solène Ferey
  • Marie Pierre Quéré
  • Fanny Lewin
  • Catherine Fallet-Bianco


MRI is a useful tool to complement US for imaging of the fetal posterior fossa (PF). In France, the discovery of a PF malformation in the fetus frequently leads to termination of pregnancy (80% in a personal series). However, despite improved accuracy in the diagnosis of PF abnormalities, prognosis remains uncertain. The first objective of this review is to document the normal MRI landmarks of the developing fetal PF. Because of their thinness, the visibility of the cerebellar fissures is dramatically delayed on MRI compared to macroscopic data. An important landmark is identification of the primary fissure of the vermis, normally seen at around 25–26 weeks’ gestation (WG) on the sagittal slice, separating the larger posterior lobe from the anterior lobe (volume ratio around 2:1). The prepyramidal and secondary fissures are usually only identifiable after 32 WG and the hemispheric fissures are difficult to see until the end of pregnancy. Considering the signal changes, high signal on T2-weighted (T2-W) sequences is seen from 25 WG in the posterior part of the brain stem (tegmentum and ascending sensory tracts) related to myelination. The low signal intensities seen within the cerebellum on T2-W images correspond to high cellularity of grey matter (deep nuclei), as there is no myelination within the white matter before 38 WG. The second objective is to highlight the signs highly predictive of a poor neurological prognosis. Lack of pontine curvature or vermian agenesis without a PF cyst (small volume of PF) is greatly associated with poor neurological status. The third objective is to propose a diagnostic strategy in difficult cases where prognosis is important, e.g. the Dandy Walker continuum. Analysis of the cerebellum is often impossible if a PF cyst is present (whatever its nature) as the mass effect usually blurs the foliation and even impairs evaluation of the normal ratio between the posterior and anterior lobes of the vermis. Isolated cerebellar hypoplasias raise the question of prognosis and genetic counselling. Such uncertainties require an amniocentesis and a careful search for other anomalies (cerebral and extracerebral). Unilateral abnormalities of a cerebellar hemisphere can be associated with good neurological status if they are isolated. The final objective is to discuss other rare PF fetal abnormalities, such as vascular malformations and tumours.


Brain Cerebellum Posterior fossa Fetus MRI 


  1. 1.
    Raybaud C, Levrier O, Brunel H, et al (2003) MR imaging of fetal brain malformations. Childs Nerv Syst 19:455–470PubMedGoogle Scholar
  2. 2.
    Philip N, Chabrol B, Lossi AM, et al (2003) Mutations in the oligophrenin-1 gene (OPHN1) cause X linked congenital cerebellar hypoplasia. J Med Genet 40:441–446CrossRefPubMedGoogle Scholar
  3. 3.
    Ramaekers VT, Heimann G, Reul J, et al (1997) Genetic disorders and cerebellar structural abnormalities in childhood. Brain 120:1739–1751CrossRefPubMedGoogle Scholar
  4. 4.
    Chance PF, Cavalier L, Satran D, et al (1999) Clinical nosologic and genetic aspects of Joubert and related syndromes. J Child Neurol 14:660–666 (discussion 669–672)PubMedGoogle Scholar
  5. 5.
    Barkovich AJ (2000) Pediatric neuroimaging, 3rd edn. Lippincott Williams and Wilkins, PhiladelphiaGoogle Scholar
  6. 6.
    Patel S, Barkovich AJ (2002) Analysis and classification of cerebellar malformations. AJNR 23:1074–1087PubMedGoogle Scholar
  7. 7.
    Adamsbaum C, Gelot A, André C, et al (2001) Atlas d’IRM du cerveau foetal, 1st edn. Masson, ParisGoogle Scholar
  8. 8.
    Girard N, Gambarelli D (2001) Normal foetal brain. Magnetic resonance imaging. Brunelle Shaw, RickmansworthGoogle Scholar
  9. 9.
    Garel C (2004) MRI of the fetal brain. Normal development and cerebral pathologies. Springer, Berlin Heidelberg New YorkGoogle Scholar
  10. 10.
    Coakley FV, Glenn OA, Qayyum A, et al (2004) Fetal MRI: a developing technique for the developing patient. AJR 182:243–252Google Scholar
  11. 11.
    Guibaud L (2004) Abnormalities of the posterior cerebral fossa. In: Garel C (ed) MRI of the fetal brain. Normal development and cerebral pathologies. Springer, Berlin Heidelberg New York, pp 217–236Google Scholar
  12. 12.
    Bernard JP, Moscoso G, Renier D, et al (2001) Cystic malformations of the posterior fossa. Prenat Diagn 21:1064–1069CrossRefPubMedGoogle Scholar
  13. 13.
    Girard N, Gire C, Sigaudy S, et al (2003) MR imaging of acquired fetal brain disorders. Childs Nerv Syst 19:490–500CrossRefPubMedGoogle Scholar
  14. 14.
    Heerschap A, van den Berg PP (1994) Proton magnetic resonance spectroscopy of human fetal brain. Am J Obstet Gynecol 170:1150–1151PubMedGoogle Scholar
  15. 15.
    Kok RD, van den Bergh AJ, Heerschap A, et al (2001) Metabolic information from the human fetal brain obtained with proton magnetic resonance spectroscopy. Am J Obstet Gynecol 185:1011–1015CrossRefPubMedGoogle Scholar
  16. 16.
    Stehling MK, Mansfield P, Ordidge RJ, et al (1990) Echo-planar imaging of the human fetus in utero. Magn Reson Med 13:314–318PubMedGoogle Scholar
  17. 17.
    O’Rahilly R, Muller F, Bossy J (1986) Atlas of the stages of development of the external forms of the brain in the human embryo. Arch Anat Histol Embryol 69:3–39Google Scholar
  18. 18.
    Larsell O, Jansen J (1972) The comparative anatomy and histology of the cerebellum. The human cerebellum, cerebellar connections and cerebellar cortex. University of Minnesota Press, MinneapolisGoogle Scholar
  19. 19.
    Wang VY, Zoghbi HY (2001) Genetic regulation of cerebellar development. Nat Rev Neurosci 2:484–491CrossRefPubMedGoogle Scholar
  20. 20.
    Alexandre P, Wassef M (2003) The isthmic organizer links anteroposterior and dorsoventral patterning in the mid/hindbrain by generating roof plate structures. Development 130:5331–5338CrossRefPubMedGoogle Scholar
  21. 21.
    ten Donkelaar HJ, Lammens M, Wesseling P, et al (2003) Development and developmental disorders of the human cerebellum. J Neurol 250:1025–1036CrossRefPubMedGoogle Scholar
  22. 22.
    Larroche C (1977) Developmental pathology of the neonate. Excerpta Medica, AmsterdamGoogle Scholar
  23. 23.
    Girard N, Raybaud C, Poncet M (1995) In vivo MR study of brain maturation in normal fetuses. AJNR Am J Neuroradiol 16:407–413PubMedGoogle Scholar
  24. 24.
    Stazzone MM, Hubbard AM, Bilaniuk LT, et al (2000) Ultrafast MR imaging of the normal posterior fossa in fetuses. AJR 175:835–839PubMedGoogle Scholar
  25. 25.
    Herrup K, Kuemerle B (1997) The compartmentalization of the cerebellum. Ann Rev Neurosci 20:61–90CrossRefPubMedGoogle Scholar
  26. 26.
    Chen S, Hillman DE (1989) Regulation of granule cell number by a predetermined number of Purkinje cells in development. Brain Res Dev Brain Res 45:137–147PubMedGoogle Scholar
  27. 27.
    Soto-Ares G, Devisme L, Jorriot S, et al (2002) Neuropathologic and MR imaging correlation in a neonatal case of cerebellar cortical dysplasia. AJNR 23:1101–1104PubMedGoogle Scholar
  28. 28.
    Goasdoue P, Rodriguez D, Moutard, ML et al (2001) Pontoneocerebellar hypoplasia: definition of MR features. Pediatr Radiol 31:613–618CrossRefPubMedGoogle Scholar
  29. 29.
    Rajab A, Mochida GH, Hill A, et al (2003) A novel form of pontocerebellar hypoplasia maps to chromosome 7q11-21. Neurology 60:1664–1667PubMedGoogle Scholar
  30. 30.
    Barth PG (1993) Pontocerebellar hypoplasias. An overview of a group of inherited neurodegenerative disorders with fetal onset. Brain Dev 15:411–422CrossRefPubMedGoogle Scholar
  31. 31.
    Zelnik N, Dobyns WB, Forem SL, et al (1996) Congenital pontocerebellar atrophy in three patients: clinical, radiologic and etiologic considerations. Neuroradiology 38:684–687CrossRefPubMedGoogle Scholar
  32. 32.
    Gadisseux JF, Rodriguez J, Lyon G (1984) Pontoneocerebellar hypoplasia—a probable consequence of prenatal destruction of the pontine nuclei and a possible role of phenytoin intoxication. Clin Neuropathol 3:160–167PubMedGoogle Scholar
  33. 33.
    Squier W, Hope PL, Lindenbaum RH (1990) Neocerebellar hypoplasia in a neonate following intra-uterine exposure to anticonvulsants. Dev Med Child Neurol 32:737–742PubMedGoogle Scholar
  34. 34.
    deSouza N, Chaudhuri R, Bingham J, et al (1994) MRI in cerebellar hypoplasia. Neuroradiology 36:148–151PubMedGoogle Scholar
  35. 35.
    Mamourian AC, Miller G (1994) Neonatal pontomedullary disconnection with aplasia or destruction of the lower brain stem: a case of pontoneocerebellar hypoplasia? AJNR 15:1483–1485PubMedGoogle Scholar
  36. 36.
    Nakamura Y, Hashimoto T, Sasaguri Y, et al (1986) Brain anomalies found in 18 trisomy: CT scanning, morphologic and morphometric study. Clin Neuropathol 5:47–52PubMedGoogle Scholar
  37. 37.
    Altman NR, Naidich TP, Braffman BH (1992) Posterior fossa malformations. AJNR 13:691–724Google Scholar
  38. 38.
    Utsunomiya H, Takano K, Ogasawara T, et al (1998) Rhombencephalosynapsis: cerebellar embryogenesis. AJNR 19:547–549Google Scholar
  39. 39.
    Truwit CL, Barkovich AJ, Shanahan R, et al (1991) MR imaging of rhombencephalosynapsis: report of three cases and review of the literature. AJNR 12:957–965Google Scholar
  40. 40.
    Rubenstein JL, Anderson S, Shi L, et al (1999) Genetic control of cortical regionalization and connectivity. Cereb Cortex 9:524–532CrossRefPubMedGoogle Scholar
  41. 41.
    Yachnis AT, Rorke LB (1999) Neuropathology of Joubert syndrome. J Child Neurol 14:655–659 (discussion 669–672)PubMedGoogle Scholar
  42. 42.
    Bromley B, Nadel AS, Pauker S, et al (1994) Closure of the cerebellar vermis: evaluation with second trimester US. Radiology 193:761–763PubMedGoogle Scholar
  43. 43.
    Adamsbaum C, Moreau V, Bulteau C, et al (1994) Vermian agenesis without posterior fossa cyst. Pediatr Radiol 24:543–546PubMedGoogle Scholar
  44. 44.
    Quisling RG, Barkovich AJ, Maria BL (1999) Magnetic resonance imaging features and classification of central nervous system malformations in Joubert syndrome. J Child Neurol 14:628–635 (Discussion 669–672)PubMedGoogle Scholar
  45. 45.
    Maria BL, Hoang KB, Tusa RJ, et al (1997) “Joubert syndrome” revisited: key ocular motor signs with magnetic resonance imaging correlation. J Child Neurol 12:423–430PubMedGoogle Scholar
  46. 46.
    Joubert M, Eisenring JJ, Robb JP, et al (1999) Familial agenesis of the cerebellar vermis: a syndrome of episodic hyperpnea, abnormal eye movements, ataxia, and retardation. 1969. J Child Neurol 14:554–564PubMedGoogle Scholar
  47. 47.
    Satran D, Pierpont ME, Dobyns WB (1999) Cerebello-oculo-renal syndromes including Arima, Senior-Loken and COACH syndromes: more than just variants of Joubert syndrome. Am J Med Genet 86:459–469CrossRefPubMedGoogle Scholar
  48. 48.
    Boltshauser E, Herdan M, Dumermuth G, et al (1981) Joubert syndrome: clinical and polygraphic observations in a further case. Neuropediatrics 12:181–191PubMedGoogle Scholar
  49. 49.
    Steinlin M, Schmid M, Landau K, et al (1997) Follow-up in children with Joubert syndrome. Neuropediatrics 28:204–211Google Scholar
  50. 50.
    Harmant-van Rijckevorsel G, Aubert-Tulkens G, Moulin D, et al (1983) Joubert syndrome. Clinical and anatomo-pathologic study. Etiopathogenetic hypotheses (in French). Rev Neurol (Paris) 139:715–724Google Scholar
  51. 51.
    Friede RL, Boltshauser E (1978) Uncommon syndromes of cerebellar vermis aplasia. I. Joubert syndrome. Dev Med Child Neurol 20:758–763PubMedGoogle Scholar
  52. 52.
    Dandy WE (1921) The diagnosis and treatment of hydrocephalus due to occlusion of the foramina of Magendie and Lushka. Surg Gynecol Obstet 32:112–124Google Scholar
  53. 53.
    Tortori-Donati P, Fondelli MP, Rossi A, et al (1996) Cystic malformations of the posterior cranial fossa originating from a defect of the posterior membranous area. Mega cisterna magna and persisting Blake’s pouch: two separate entities. Childs Nerv Syst 12:303–308PubMedGoogle Scholar
  54. 54.
    Calabro F, Arcuri T, Jinkins JR (2000) Blake’s pouch cyst: an entity within the Dandy-Walker continuum. Neuroradiology 42:290–295CrossRefPubMedGoogle Scholar
  55. 55.
    Barkovich AJ, Kjos BO, Norman D, et al (1989) Revised classification of posterior fossa cysts and cystlike malformations based on the results of multiplanar MR imaging. AJR 153:1289–1300PubMedGoogle Scholar
  56. 56.
    Raybaud C (1982) Cystic malformations of the posterior fossa. Abnormalities associated with the development of the roof of the fourth ventricle and adjacent meningeal structures. J Neuroradiol 9:103–133PubMedGoogle Scholar
  57. 57.
    Osaka K, Handa H, Matsumoto S, et al (1980) Development of the cerebrospinal fluid pathway in the normal and abnormal human embryos. Childs Brain 6:26–38PubMedGoogle Scholar
  58. 58.
    Blake J (1900) The roof and lateral recesses of the fourth ventricle, considered morphologically and embryologically. J Comp Neurol 10:79–108Google Scholar
  59. 59.
    Murray JC, Johnson JA, Bird TD (1985) Dandy-Walker malformation: etiologic heterogeneity and empiric recurrence risks. Clin Genet 28:272–283PubMedGoogle Scholar
  60. 60.
    Bordarier C, Aicardi J (1990) Dandy-Walker syndrome and agenesis of the cerebellar vermis: diagnostic problems and genetic counselling. Dev Med Child Neurol 32:285–294PubMedGoogle Scholar
  61. 61.
    Chang MC, Russell SA, Callen PW, et al (1994) Sonographic detection of inferior vermian agenesis in Dandy-Walker malformations: prognostic implications. Radiology 193:765–770PubMedGoogle Scholar
  62. 62.
    Ecker JL, Shipp TD, Bromley B, et al (2000) The sonographic diagnosis of Dandy-Walker and Dandy-Walker variant: associated findings and outcomes. Prenat Diagn 20:328–332CrossRefPubMedGoogle Scholar
  63. 63.
    Klein O, Pierre-Kahn A, Boddaert N, et al (2003) Dandy-Walker malformation: prenatal diagnosis and prognosis. Childs Nerv Syst 19:484–489CrossRefPubMedGoogle Scholar
  64. 64.
    Estroff JA, Scott MR, Benacerraf BR (1992) Dandy-Walker variant: prenatal sonographic features and clinical outcome. Radiology 185:755–758PubMedGoogle Scholar
  65. 65.
    Villeneuve N (1990) Syndromes d’hypoglycosylation des protéines. In: Arthuis M, Pinsard N, Ponsot G (eds) Neurologie pédiatrique. Médecine Sciences, Flammarion, Paris, pp 748–752Google Scholar
  66. 66.
    Antoun H, Villeneuve N, Gelot A, et al (1999) Cerebellar atrophy: an important feature of carbohydrate deficient glycoprotein syndrome type 1. Pediatr Radiol 29:194–198CrossRefPubMedGoogle Scholar
  67. 67.
    Brunel H, Girard N, Confort-Gouny S, et al (2004) Fetal brain injury. J Neuroradiol 31:123–137PubMedGoogle Scholar
  68. 68.
    Adamsbaum C, Merzoug V, Andre C, et al (2002) Prenatal diagnosis of isolated posterior fossa anomalies: attempt at a simplified approach (in French). J Radiol 83:321–328PubMedGoogle Scholar
  69. 69.
    Sasaki M, Oikawa H, Ehara S, et al (2001) Disorganised unilateral cerebellar folia: a mild form of cerebellar cortical dysplasia? Neuroradiology 43:151–155CrossRefPubMedGoogle Scholar
  70. 70.
    Boltshauser E, Steinlin M, Martin E, et al (1996) Unilateral cerebellar aplasia. Neuropediatrics 27:50–53PubMedGoogle Scholar
  71. 71.
    Soto-Ares G, Delmaire C, Deries B, et al (2000) Cerebellar cortical dysplasia: MR findings in a complex entity. AJNR 21:1511–1519PubMedGoogle Scholar
  72. 72.
    Liliequist B (1959) The subarachnoid cisterns. An anatomic and roentgenologic study. Acta Radiol Suppl 185:1–108Google Scholar
  73. 73.
    Lee RR, Becher MW, Benson ML, et al (1997) Brain capillary telangiectasia: MR imaging appearance and clinicohistopathologic findings. Radiology 205:797–805PubMedGoogle Scholar
  74. 74.
    Lasjaunias P (1997) Vascular diseases in neonates, infants and children. Springer, Berlin Heidelberg New YorkGoogle Scholar
  75. 75.
    Guibaud L, Pelizzari M, Guibal AL, et al (1996) Slow-flow vascular malformation of the pons: congenital or acquired capillary telangiectasia. AJNR 17:1798–1799; author reply 1799–1800Google Scholar
  76. 76.
    Barr RM, Dillon WP, Wilson CB (1996) Slow-flow vascular malformations of the pons: capillary telangiectasias? AJNR 17:71–78PubMedGoogle Scholar
  77. 77.
    Kuker W, Nacimiento W, Block F, et al (2000) Presumed capillary telangiectasia of the pons: MRI and follow-up. Eur Radiol 10:945–950CrossRefPubMedGoogle Scholar
  78. 78.
    Molina CP, Hawkins H, Campbell G, et al (1999) Case of the month: January 1999—fetus with echogenic mass in third ventricle. Brain Pathol 9:605–606PubMedGoogle Scholar
  79. 79.
    D’Addario V, Pinto V, Meo F, et al (1998) The specificity of ultrasound in the detection of fetal intracranial tumors. J Perinat Med 26:480–485PubMedGoogle Scholar
  80. 80.
    Mitchell D, Rojiani AM, Richards, D et al (1995) Congenital CNS primitive neuroectodermal tumor: case report and review of the literature. Pediatr Pathol Lab Med 15:949–956PubMedGoogle Scholar
  81. 81.
    Yamada T, Takeuchi K, Masuda Y, et al (2003) Prenatal imaging of congenital cerebral primitive neuroectodermal tumor. Fetal Diagn Ther 18:137–139CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Catherine Adamsbaum
    • 1
  • Marie Laure Moutard
    • 2
  • Christine André
    • 1
  • Valérie Merzoug
    • 1
  • Solène Ferey
    • 1
  • Marie Pierre Quéré
    • 3
  • Fanny Lewin
    • 4
  • Catherine Fallet-Bianco
    • 5
  1. 1.Department of RadiologySt Vincent de Paul HospitalParis Cedex 14France
  2. 2.Department of NeuropaediatricsSt Vincent de Paul HospitalParisFrance
  3. 3.Department of RadiologyCHUNantesFrance
  4. 4.Maternity DepartmentSt Vincent de Paul HospitalParisFrance
  5. 5.Department of NeuropathologySte Anne HospitalParisFrance

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