Chiari I malformation: Association with hypophosphatemic rickets and MR imaging appearance

Karen S. Caldemeyer, Joel C. Boaz, Rebecca S. Wappner, Catherine C. Moran, Richard R. Smith, Jerome P. Quets

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PURPOSE: To evaluate for an association between familial hypophosphatemic rickets (FHR) and Chiari I malformation (CM1). MATERIALS AND METHODS: Sixteen patients with FHR underwent magnetic resonance (MR) imaging of the cervicomedullary junction. Images were analyzed by three radiologists for cerebellar tonsillar ectopia, syringohydromyelia, calvarial bone thickening, a flat posterior fossa, and cervical spinal stenosis. Final diagnoses were made by means of consensus. Tonsillar ectopia of 4 mm indicated CM1. Subjects underwent neurologic examination and completed a questionnaire. Medical records were retrospectively reviewed. A two-sided Fisher exact test was used to test for independence between CM1 and bone thickening or ventriculomegaly. RESULTS: Seven subjects (44%) had CM1. The more severe the bone thickening, the more likely that a CM1 was present. Four subjects (25%) had cervical spinal stenosis. CONCLUSION: Findings indicate that CM1 is associated with FHR and that the primary abnormality in patients with CM1 is a small posterior fossa caused by a bony malformation.

Original languageEnglish (US)
Pages (from-to)733-738
Number of pages6
Issue number3
StatePublished - Jun 1995



  • Brain, abnormalities
  • Rickets

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology

Cite this

Chiari I malformation : Association with hypophosphatemic rickets and MR imaging appearance. / Caldemeyer, Karen S.; Boaz, Joel C.; Wappner, Rebecca S.; Moran, Catherine C.; Smith, Richard R.; Quets, Jerome P.

In: Radiology, Vol. 195, No. 3, 06.1995, p. 733-738.

Research output: Contribution to journalArticle