title: Holoprosencephaly: an analysis of callosal formation and its relation to development of the interhemispheric fissure.
abstract: OBJECTIVE
  To correlate the degree of hemispheric fusion in holoprosencephaly with degree of callosal formation, with degree of thalamic and basal ganglia fusion, and with presence or absence of dorsal cyst.
  
  
  METHODS
  MR, CT, and ultrasonography from 19 patients with holoprosencephaly was retrospectively reviewed. The imaging studies were graded according to extent of the hemispheric fusion, thalamic fusion, corpus striatum fusion, callosal formation, and the presence or absence of a dorsal cyst. These factors were statistically correlated with each other using Kendall rank correlation coefficient.
  
  
  RESULTS
  There were significant correlations between hemispheric fusion and failure of corpus callosum formation, presence of dorsal cyst and failure of corpus callosum formation, and hemispheric fusion and presence of dorsal cyst. Additional correlations were noted between thalamic fusion and corpus striatum fusion.
  
  
  CONCLUSIONS
  Our results suggest that the presence of an interhemispheric fissure is necessary for callosal formation, and the presence of a dorsal cyst may interfere with callosal formation in holoprosencephaly.
authors.affiliation: Department of Radiology, University of California, San Francisco 94143-0628, USA.
authors.forename: H
authors.initials: H
authors.lastname: Oba
authors.forename: A J
authors.initials: AJ
authors.lastname: Barkovich
mesh_terms: D061085:Agenesis of Corpus Callosum; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003337:Corpus Callosum / Q000473:pathology; D003342:Corpus Striatum / Q000002:abnormalities / Q000473:pathology; D003560:Cysts / Q000151:congenital / Q000175:diagnosis; D003952:Diagnostic Imaging; D004292:Dominance, Cerebral / Q000502:physiology*; D005260:Female; D016142:Holoprosencephaly / Q000145:classification / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009434:Neural Pathways / Q000002:abnormalities / Q000473:pathology; D012189:Retrospective Studies; D013788:Thalamus / Q000002:abnormalities / Q000473:pathology