Pituitary height grading describes degrees of loss of the pituitary height (concavity), which encompasses gradations of (partially) empty sella.
Grading
As originally described by Yuh et al. 1, the loss of pituitary height (h) and the sellar height (H) are measured on a midsagittal T1-weighted image and described in the following "categories" (grades):
- I: normal appearance (superior aspect of the gland is convex or flat)
- II: mild loss of pituitary height (h < ⅓ H)
- III: moderate loss of pituitary height (⅓ H < h < ⅔ H)
- IV: severe loss of pituitary height (h > ⅔ H)
- V: no pituitary parenchyma observed and enlarged sella turcica (total empty sella)
Significance
In the original study, at least moderate concavity (category III) pituitary morphology had a sensitivity of 80% and specificity of 92% for the diagnosis of idiopathic intracranial hypertension compared to patients who are normal or have acutely increased intracranial pressure 1.
Pituitary height loss grade shows age-related increases in patients with idiopathic intracranial hypertension but not incidental partially empty sella 2. Among patients with idiopathic intracranial hypertension, higher pituitary grade is associated with higher likelihood of having a cephalocele, suggesting a common mechanism 3.
Higher pituitary grades have been implicated in empty sella syndromes characterized by pituitary dysfunction, such as Cushing syndrome, without a mass identified on MRI 4.