Technique: Multiplanar, multisequence images were acquired including volumetric T1 weighted images and post-contrast images.
Findings: The septum pellucidum is noted to be absent and there is a flattening of the roof of the anterior horns of the lateral ventricles. The optic chiasm is not small and no features to suggest a lobar holoprosencephaly. No schizencephaly, cortical dysplasia or gray matter heterotopia.
The ventricles are the fourth and third ventricles are slightly large, but no transependymal oedema to suggest this might represent acute hydrocephalus. The cerebral aqueduct is narrowed by a cystic structure in the pineal gland measuring 14 x 15 x 13 mm, which has thin internal septations within it.
The calcified focus in the left cavernous sinus is better assessed on the CT and is shown on MR as a focus of susceptibility artefact at this site of dubious clinical significance. No mass lesion identified at this site.
No parenchymal susceptibility artefact.
Conclusion: Absent septum pellucidum, but no features to suggest a lobar holoprosencephaly and the optic chiasm is not small to suggest a septo-optic dysplasia. Cystic pineal lesion, probably a pineal cyst, however, the thin internal septations and size means follow up imaging is probably warranted to exclude a pineocytoma. The lateral and third ventricles are slightly dilated, which could be due to narrowing of the cerebral aqueduct by the cystic pineal lesion.