Learning objectives
To provide a recapitulation of the blood-brain barrier and physics ofMR contrast media used in neuroradiology.
To provide a pictorial review of thepatterns of contrast enhancement encountered in neuroradiology.
Background
REVIEW OF THE MENINGES (1)
The neuraxis is encased by3 protective coats collectively called the meninges.
Theselayers are called dura mater,arachnoid mater,
andpia mater.
1.
Dura mater:
The dura mater (DM) isthe outermost fibrous covering of the brain,
rich in neurovascular supply.It is also called pachymeninges (Greek: pachy = thick).It ensheathes the cranial nerves and fuses with the epicranium.
The dura also folds upon itself to partition the cranial cavity (falx cerebri,falx cerebelliand tentorium cerebelli).
2.
Arachnoid mater:
The arachnoid mater (AM) isthemiddle meningeal layer....
Findings and procedure details
PACHYMENINGEALENHANCEMENT (PE)
PEis best appreciated on a contrast-enhanced MRI (CE-MRI).(14,
15) The dura is devoid of the BBB and is permeable to contrast.
PE is seen along the cerebral convexities or its reflections.(14)Thin,
discontinuous enhancement may be normal.(15)
Post-operativePE is does not necessarily indicate recurrence.
Surgically induced PE is attributed to an inflammatory response or chemical arachnoiditis secondary intra-operative bleeding.(16)A follow-up to ensure interval stability or regression, is recommended.
Intracranial hypotension(IH)may be due to traumatic injury or may be idiopathic.
(17) Diffuse PE is a...
Conclusion
Contrast mediahas facilitated the uncovering of pathologies,
otherwise imperceptible.Understanding of certain nomenclature is essential in the justification of an imaging differential.This exhibit attempts to simplify key concepts in the interpretation of tell-tale patterns of enhancement in and around the brain.
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