Identification of optimal surgical intervention for Chiari I malformation

Chiari I Malformation (CM-I) is a disorder characterized by herniation of the cerebellar tonsils through the foramen magnum. The choice of the optimal surgical management of CM-I is still an open problem, as there are no guidelines for the most suitable approach in symptomatic patients. We assessed the possibility of predicting the optimal intervention on the basis of morphological properties of the brain, posterior fossa and cerebellum. The boundaries of these regions were estimated by non-rigid registration of test sagittal magnetic resonance images (MRI) over an atlas. Different features characterizing the estimated regions were extracted and used to develop Naive Bayes classifiers. Classification was tested on a database of 30 patients, which were either healthy or pathological, with either mild or severe manifestation of CM-I. The best cross-validated classifier selected input features related to the shape and relative dimension of different brain regions (specifically, cerebellum and posterior fossa), the possible presence and dimension of the hernia and the regularity of the boundary of the cerebellum. The best classification accuracy (tested with a leave-one-out approach) was about 83%. These promising results suggest investigating further the possibility of defining the surgical treatment of CM-I on the basis of morphometric parameters from sagittal MRIs.