MRI Cystic conditions Flashcards
(16 cards)
What is hydranencephaly?
Complete destruction or lack of development of the neocortex due to process occurring in utero, likely viral infection
Involves unilateral or bilateral reduction of size of cerebral cortex to a thin mantle surrounding a large fluid-filled cavity contiguous with lateral ventricle.
What are the key features of porencephaly?
Cystic cavity in cerebrum due to cell destruction or failure of development
Features include unilateral or bilateral, single or multiple, commonly wedge-shaped cavities that may communicate with ventricles or subarachnoid space.
What are intracranial intra-arachnoid diverticula?
Arise from splitting/duplication of arachnoid and occur in close association with intracranial arachnoid cisterns
Include three patterns of expansion related to the 3rd ventricle and quadrigeminal cistern.
Describe Pattern 1 of intracranial intra-arachnoid diverticula.
Most common pattern: Caudodorsal expansion of the 3rd ventricle with normal or minimally enlarged quadrigeminal cistern
This pattern is characterized by a specific configuration of the ventricles.
What is the MRI finding for intracranial intra-arachnoid diverticula?
Sharply demarcated lesions dorsal to the quadrigeminal plate or associated with the 4th ventricle
Lesions contain fluid isointense to CSF and may cause flattening, compression, or displacement of adjacent structures.
What are the possible changes associated with intracranial intra-arachnoid diverticula?
Obstructive hydrocephalus, altered signal intensity of fluid due to hemorrhage, concurrent syringohydromyelia in cervical spinal cord
The relationship between size of lesion and clinical signs in quadrigeminal region cysts is important.
True or False: Cysts causing >14% compression of the occipital lobe on mid-sagittal images are always associated with clinical signs.
True
There is no association between degree of cerebellar compression and clinical signs.
What causes intracranial epidermoid cysts (cholesteatoma) and dermoid cysts?
Failure of neural tube closure when epithelial ectoderm becomes entrapped within nervous tissue
These cysts form a slowly expanding cystic mass.
What are the MRI findings for epidermoid cysts?
Usually heterogeneous T2/FLAIR hyperintense, T1 hypointense, may contain internal separations and show ring enhancement
Dermoid cysts typically have fat content and show different signal characteristics.
What is Rathke’s cleft cyst?
Arises from failure of obliteration of the lumen of the Rathke’s pouch
Contains mucoid or serous fluid and cellular debris.
What are the MRI findings for Rathke’s cleft cyst?
Single or loculated cystic lesions within the pituitary fossa with or without suprasellar extension
T1 hypointense, T2 hyperintense, and may not suppress on FLAIR.
What are ependymal cysts?
Well-circumscribed cystic lesion filled with fluid similar to CSF
They are typically benign and do not usually cause symptoms.
What are choroid plexus cysts?
Well-circumscribed lesions, typically isointense to CSF, but may be altered by variations in protein content
Can be non-enhancing, ring enhancing, or strongly enhancing.
What is hydrocephalus ex vacuo?
Compensatory hydrocephalus resulting from replacement of parenchyma with fluid
Characterized by variably sized and shaped lesions isointense to CSF.
What is neurocysticercosis?
Infection with cystic larvae of Taenia solium
This infection can lead to various cystic intracranial masses.
Name some tumors that may have a cystic component.
- Meningiomas
- Gliomas
- Choroid plexus tumors
- Nasal tumors
- Intracranial extension of nasal mucoceles
These tumors can present challenges in diagnosis and treatment.
