NeuroradiologyEmpty sella
condition in which the content of the sella is mainly composed of CSF-filled subarachnoid space; the
pituitary gland is present but usually flattened over the sella floor and the
pituitary stalk is slightly stretched. The bony sellar cavity may be of normal volume or slightly enlarged.
From a clinical point of view an empty sella may be asymptomatic or accompanied by headache, blurred vision, visual field defects and mild endocrinopathies like obesity, hypopituitarism and hyperprolactinaemia. Sometimes associated papilloedema is found.
No definitive explanation for empty sella formation exists. Absent diaphragma sellae, a focal abnormality of the formation of the dura and arachnoid in the sellar region and subclinical raised intracranial pressure due to abnormal CSF circulation have been suggested.
From a neuroradiological point of view, plain film may show a slightly enlarged sella without significant floor erosion, CT shows an hypodense content while MR better demonstrates, on both sagittal and coronal T1- and T2-weighted images the CSF signal within the sella cavity, the flattened and thinned pituitary and the stretched stalk (Fig.1).
When present, enlargement of the subarachnoid space of the optic nerve sheath may be demonstrated.
A differential diagnosis must be made with rare intrasellar dermoids or arachnoid cyst (although the empty sella itself could be classified in this category).
GS
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Midline, lateral T1-weighted MR image shows enlargement of the sella turcica, CSF occupying almost the entire sella cavity, flattening of the pituitary gland on the sellar floor and stretching of the pituitary stalk. The patient also has a craniovertebral junction anomaly.
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Empty sella, Fig.1 | |