Diagnostic Imaging for Pituitary Disorders
To diagnose pituitary disorders, magnetic resonance imaging (MRI)
is performed either with or without contrast enhancement. The
normal brain has a blood-brain-barrier through which contrast
cannot pass, so contrast does not show up on magnetic
resonance images of a normal brain. Tumors, especially
vascular tumors, do not have a blood-brain-barrier.
Therefore, contrast enters tumors and enhances (shows up as a
bright area on magnetic resonance images) on a contrasted
magnetic resonance image. The pituitary gland and stalk also
do not have a blood-brain-barrier, so they too appear as
bright areas on contrasted MRIs.
Left. Sagittal precontrast T1-weighted magnetic resonance image
shows a normal-appearing pituitary gland. The anterior lobe of the
pituitary is isointense and the posterior lobe is hyperintense.
Right. Sagittal postcontrast T1-weighted magnetic resonance image
shows normal diffuse enhancement of the pituitary gland.
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Left. Coronal precontrast T1-weighted magnetic resonance image
shows the infundibulum, optic chiasm, and cavernous sinuses. Right.
Fat-saturated coronal postcontrast T1-weighted magnetic resonance
image is useful for assessing the pituitary gland for residual
tumor or for a recurrence after surgery.
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