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Articles » Magnetic Resonance Imaging » MRI, Central nervous system
2005-10-24-11 MRI, holoprosencephaly © Werner


Heron Werner, MD*,Pedro Daltro, MD*, Dorothy Bulas, MD #

* Heron Werner, MD
Clínica de Diagnóstico por Imagem (CDPI) & Instituto Fernandes Figueira (IFF) – FIOCRUZ
Rio de Janeiro – Brazil

# Dorothy I. Bulas M.D.
Professor of Radiology and Pediatrics
Children"s National Medical Center
George Washington University Medical Center
111 Michigan Ave, NW,   Washington D.C. 20010

There have been reports of sporadic cases of holoprosencephaly recognized by MRI. This is a pathology with precocious origin (during the organogenesis of the brain, that originates from a cleavage failure of the primitive prosencephalon. Its incidence is of around 1 out of 10.000 births (Sanders, 1996). According to its level of severity, holoprosencephaly is classified in alobar, semilobar and lobar (Table 1). Despite few accounts in literature, MRI does seem to be beneficial to characterizing an intrauterine lobar holoprosencephaly, enabling a more precise differential evaluation with agenesis of the corpus callosum and Dandy-Walker deformity (Girard, 1993; Lair-Milar, 1997).

Fetuses with holoprosencephaly of both the alobar and semilobar types tend to die at birth. Survival relates to the most mild forms of the disorder, including the lobar type, and is associated with mental retardation.

Findings   Alobar  Semilobar Lobar 
 Craniofacial anomaly  Severe  Variable  Mild or absent
 Ventricles  Mono ventricle   Rudimentary occipital horns       Frontal horns with either a rectangular aspect
 Pellucid septum  Absent   Absent   Absent
 Falx cerebri   Absent  Partial  Well developed
 Inter hemispheric fissure   Absent  Partial  Present; some anteroinferior fusion
 Thalamus, basal ganglia  Fused  Partial  Separated


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