Interpretation of MRI pituitary

3. MRI PITUITARY
PROTOCOL
• T1W
– sequence: coronal and sagittal
– purpose: useful for anatomical depiction, mainly the posterior pituitary
bright spot
• T2W
– sequence: coronal (axial/sagittal for high resolution)
– purpose: identify blood product or dot sign in Rathke cleft cyst
: to visualize the diaphragma sellae and arterial flow voids
• DWI/ADC and FLAIR

4. • T1 C+ dynamic
sequence: coronal, obtained at multiple locations through the pituitary
gland at multiple time points
purpose: identify microadenoma (which have delayed enhancement) and
: identify displaced normal pituitary gland by a sellar mass,
: to differentiate residual or a recurrent tumor from postoperative
tissues
• T1 C+ delayed
sequence: coronal and sagittal
purpose: to assess the cavernous sinuses and to characterize other sellar
region tumors

5. Normal anatomy of the pituitary gland and surrounding
structures:
• Pituitary gland
• Cavernous sinus
• Optic nerve/ optic chiasm and optic tract
• Suprasellar cystern
• Third ventricle
Relation
• located within the pituitary fossa
• inferiorly
– Inferior intercavernous sinus
– Sphenoid bone
– Sphenoid sinus

6. Superiorly
Diaphragma sellae
Suprasellar cystern
Pituitary stalk
Optic chiasm
Circle of willis
hypothalamus
Laterally
Cavernous sinus
Anteriorly
anterior intercavernous sinus
anterior clinoid processes
Posteriorly
posterior intercavernous sinus
dorsum sellae

7. • Age-dependent changes
• The pituitary gland volume changes on hormonal status
• Larger gland in young and the largest in hormonally active state such as
puberty an pregnancy
convex upper border
• Elderly have thinned gland lying on the floor of the sella .
• Height of the gland 1:
- children (<12 years): 6mm
- puberty: 10 mm young adult
-male: 8 mm
-female: 9 mm
-pregnancy: 12 mm
• older adult (>50 years): gradually decreases in size

8. INTERPRETATION
• Normal signal change of anterior and posterior pat of the pituitary
T1W T2W
Anterior isointense isointense
Posterior high lo
• Posterior pituitary bright spot- in T1W
• Infundibulum – midline
• Diaphragma sellae and boundaries of pituitary fossa - enlargement or
erosion
• Optic chiasm relationship to pituitary
pre fixed- above tuberculum sellae
pot fixed- above dorsum sellae
Optic nerve signal change ( T2W coronal)

9. • Bone marrowsignal of clivus
compare the marrow ith adjacent pons
(non-contrast, non-fat saturated T1 sequences -. Sagittal plane).
• Cavernous sinuses and Meckel's caves- symmetry
• Visible arteries - aneurysms or malformations

10. PIYUITARY MASSES
Patterns of morphology:
• solid and enhancing pituitary region mass
• mixed cystic and solid pituitary region mass
• cystic pituitary region mass
Patterns of location:
• purely intrasellar pituitary mass
• purely suprasellar
• both supra and intrasellar

11. Helpful signs
• dural tail: meningioma, hypophysitis, and metastases
• diaphragma sella displacement: up vs. down
• carotid narrowing: meningioma
• erosion of sella: metastasis

12. • Mass
– size in three dimensions
– necrotic/cystic areas
– size of diaphragmatic opening and size of the suprasellar
component:
– presence of prolapse of the suprasellar membrane:
• in front of the tumor (visible as a little cleft of CSF in front of the
mass)
• Increase risk of an intraoperative CSF leak
– presence of invasion into the cavernous sinus/clivus/sphenoid
sinus/orbit
– location of normal pituitary tissue and infundibulum in relation
to the mass
• Vessels
– medially located or aberrant carotid arteries
– Aneurysms/vascular anomalies especially in the cavernous
sinuses

13. • Bone
– size of the bony sella -expansion
– degree of pneumatization of the sphenoid, location of the
sphenoid septum and any anomalous sinus anatomy
• best - CT
• post-contrast coronal T1W images
• location of sphenoid septum guide the transsphenoidal
approach
– bony dehiscence over the carotid arteries in the sphenoid (better
seen on CT)
– presence of florid sinus disease, nasal polyps, septal spurs