Evaluate for lesion in periaquaductal grey matter; cyclic vomiting. The cerebellar tonsils extend up to 5 mm inferior to the foramen magnum and display slightly pointed morphologies. The posterior fossa also appears to have a rather small capacity. There is no evidence of lesions in the periaqueductal region or elsewhere in the brainstem otherwise. There is no evidence of intracranial hemorrhage, mass, or acute infarct. The brain parenchyma and pituitary gland appear unremarkable. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift. The major cerebral flow voids are intact. The orbits, paranasal sinuses, and scalp soft tissues are grossly unremarkable.
1. Findings suggestive of possible Chiari type 1 malformation.2. Left tympanomastoid fluid may represent otomastoiditis.