Chiari Malformation Workup

Updated: Sep 27, 2018
  • Author: Peyman Pakzaban, MD; Chief Editor: Brian H Kopell, MD  more...
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Imaging Studies

MRI is the most useful and most widely used imaging study for diagnosing Chiari malformation. In addition to depicting the anatomy of the craniocervical junction, it provides useful information about associated abnormalities, such as syringomyelia and hydrocephalus. [8]

Patients who cannot undergo MRI can be evaluated with CT-myelography/cisternography. However, the increasing availability of high-resolution high-speed (eg, 64-slice) CT scanners allows for making the diagnosis with a noncontrast CT with sagittal reconstructions, obviating the need for myelography.

CSF flow analysis through foramen magnum with phase-contrast cine MRI helps distinguish symptomatic Chiari I from asymptomatic cerebellar ectopia [6] and helps predict response to surgical decompression. [7]

CSF flow study with phase-contrast cine MRI. Brain CSF flow study with phase-contrast cine MRI. Brain pulsations results in caudad and cephalad flow of CSF across foramen magnum during systole and diastole. The reversal in the direction of flow is picked up by alternating light and dark appearance of CSF in front and behind the medulla and upper spinal cord on phase-contrast cine MRI. In this case of Chiari I malformation, note the complete absence of CSF flow behind (arrowheads) and focal constriction of CSF flow (arrows) in front of cervicomedullary junction.

Laboratory Studies

Lab studies are not applicable for diagnosing Chiari malformations.

Preparation for surgery for Chiari I decompression is the same as for any elective surgery and depends on the patient's general health. The author routinely obtains CBC, basal metabolic panel, PT, aPTT, chest radiograph, and ECG. Blood is typed and screened.