Pituitary fossa

Question 1

What are the different classification of pituitary tumours?

Answer 1

Benign adenomas
cause Acromegaly

Malignant carcinoma

Miscellaneous group
craniopharyngioma (usually suprasella)
dermoid cysts
teratomas

Question 2

How would you identify if there is a tumour

Answer 2

Shape
especially of floor
Enlargement
due to SOL (space occupying lesion)
Bony erosion
due to pressure of enlarging pituitary gland

Question 3

What are the regular images for the pituitary fossa?

Answer 3

Coned Lateral
Slit 30o Townes
Slit 10o OF (PA) optional

Question 4

What is the CP for pit fossa lat view?

Answer 4

1 inch anterior and superior to EAM

Question 5

What is the radiographic critique of a lateral pit fossa xray?

Answer 5

Radiographic criteria;
Sella turcica & clivus are seen in profile.
Anterior & posterior clinoids superimposed. (no rotation)
Sphenoid: greater & lesser wings superimposed (no tilt)
Density & radiographic contrast are sufficient to clearly visualise sella turcica

Question 6

Position and critique a modified 30 or 37 degree townes.

Answer 6

Position as for Townes skull (OMBL zero)
Central Ray
300 caudal
Centre Point (modified) 
 midpoint through line joining EAMs (4cm – not usual 6.5 cm superior to glabella)
Demonstrate dorsum sellae
anterior & posterior clinoid processes        into the foramen magnum
Angle is chosen dependent on ROI

CR 30 degree caudal
If anterior clinoids are of primary interest

CR 37 degree caudal
If dorsum sella & posterior clinoids are of primary interest.

Question 7

Citique a slit 30 townes

Answer 7

No rotation as evidence by symmetric petrous ridges & equal distances from MSP (IDed by perpendicular plate of ethmoid)

10cm x 10cm tight coning with dorsum sellae in centre.

Question 8

What are the supplementary imaging for a pit fossa

Answer 8

CT or MR are the gold standard for imaging the pituitary fossa.