MRI versus conventional radiologic examinations in the evaluation of the craniovertebral and cervicomedullary junction.

MRI is superior to conventional radiographic techniques for demonstrating anatomic CMJ distortion and compression in all patients, regardless of the pathology involved. Because of the high incidence of osseous CVJ abnormalities in patients with a Chiari malformation, complete evaluation of these patients requires examination of the osseous CVJ by conventional radiographic methods in addition to the MRI study. Conventional techniques are also helpful for the complete evaluation of inflammatory and osseous lesions involving the CVJ. Occasionally, designation of tumors as intra- or extraaxial may not be possible by MRI alone; additional studies may be necessary. The failure of MRI to demonstrate calcification is a limitation in the evaluation of a variety of pathologic entities, especially neoplasms in which the demonstration of calcification may be a clue to the histologic diagnosis.