Evaluate for Chiari. Non-enhanced CT:This examination was tailored to include the upper cervical spine to facilitate detection of Chiari malformation as clinically is questioned.There is no evidence of intracranial hemorrhage, edema, midline shift or hydrocephalus.Images through posterior fossa as well as reformatted sagittal and coronal 2-D images demonstrate 18-mm upward herniation of the dens through the foramen magnum into the posterior fossa. There is evidence of platybasia.The anatomical orientation of the articulation of occipital condyles with lateral mass of C1 are abnormal and they appear more vertical in orientation. There is suggestion of at least partial fusion of the right lateral mass of C1 with the occipital condyles. There is no fusion of the lateral mass of C1 with the occipital condyles on the left. There is fusion of the anterior arch of C1 to the anterior lip of foramen magnum. There is apparent fusion of the posterior elements of C1 with C2. There is no fusion of the articulating facets of C1 and C2. Sagittal reformatted images demonstrate mass effect and posterior displacement of medulla by the upwardly herniated dens and there is no detectable subarachnoid space at this level. There is suggestion of possible herniation of cerebellar tonsils anterior to the posterior nipple foramina magnum. Recommend further follow-up with an MRI examination for better assessment.
1.No evidence of intracranial pathology or brain parenchyma.2.Platybasia and upward herniation of dens of approximately 18 mm through the foramina magnum.3.Congenital anatomical variation of fusion of anterior arch of C1 to the anterior lip of the foramen magnum, partial fusion of the right occipital condyles and lateral mass of C1 and partial fusion of posterior elements of C1 and C2.4.Above findings were discussed with the referring clinical physician Dr. Ben Roitberg at the time of interpretation.