Comment on: “sagittal MRI often overestimates the degree of cerebellar tonsillar ectopia: a potential for misdiagnosis of the Chiari I malformation”, by R. Shane Tubbs et al.

Excerpt

This paper by Tubbs et al. [1] is important because it stresses a major point in radiologic methodology; one should never rely on a single imaging plane. In the instance of the Chiari 1 deformity, the authors demonstrate that the use of coronal images provides a more precise evaluation of the tonsillar descent with very simple landmarks, shows to better advantage the usual asymmetry of the herniation (interestingly, they also illustrate a correlation of the asymmetry with the associated spinal cord abnormalities), and allows a more reliable comparison between the pre-operative findings and post-operative results. As a neuroradiologist, I would add that coronal images are needed because they may also complement the etiologic assessment by demonstrating a shallowness of the posterior fossa, in particular, a true basal invagination (the foramen magnum located above the bottom of the posterior fossa), which cannot be easily diagnosed on sagittal images. …