Type:
Educational Exhibit
Keywords:
CNS, Head and neck, Anatomy, MR, Image manipulation / Reconstruction, Diagnostic procedure, Contrast agent-intravenous, Imaging sequences, Endocrine disorders, Genetic defects, Trauma
Authors:
I.-V. A. MALLA HOUECH, D. Zlatareva, H. Malla Houech, A. Nankova; Sofia/BG
DOI:
10.26044/ecr2019/C-3403
Background
Ectopic Neurohypophysis (EN) is a rare condition characterized mainly by lower growth hormone levels but panhypopituitarism is also observed.
Its incidence in population ranges from 0.5-1/1mln live births.
Most commonly affected are males.
Predisposing factors can be:
- prenatal genetic,
- complicated breech delivery,
- head trauma
- it can be association with other conditions such as corpus callosum and ventricular dysplasia,
migration disorders as grey matter heterotopy.
Imaging methods of choice is Magnetic resonance technique with gadolinium enhancement.
CT is used as a basic overview or in the cases MR is contraindicated
Advantages of MR include:
- non-ionizing radiation
- better temporal resolution in the sellar and parasellar region
- great for initial diagnosis and follow up
CT scan allows:
- assessing bone structures
- Rough review when MR in contraindicated in patients with pacemakers,
metallic prosthetics or suffering claustrophobia.
Normal anatomy of the pituitary gland
It consists of an anterior,
posterior and intermediate part.
The last one is a rudimentary structure,
it usually gives rise to a Rathke’s cleft cyst.
The communication with the hypothalamus is carried out by the infundibulum.
The golden standard for imaging is MRI.
The anterior part has the same signal intensity as the pons,
which is used as a reference.
The posterior part is usually bright on T1 images,
the so called “T1 posterior pituitary bright spot”.
This is due to the neurosecretory granules containing vasopressin.
In 20% of population this bright spot is absent,
but it is not associated with any anomalous condition.
The bright spot of the posterior hypophysis in children indicates that the child is well hydrated.