Neuro -- Dural/leptomeningeal Processes

Front 1

What is the DDX of dural or leptomeningeal thickening/ enhancement?

Back 1

MALIGNANT:
- Carcinomatous meningitis
- Lymphomatous meningitis
INFLAMMATORY:
- Sarcoid, Wegeners granulomatosis
INFECTIOUS:
- Bacterial, TB, Fungal
IATROGENIC:
- Post-operative/post shunt
- Severe leptomeningeal irritation 2/2 subarachnoid hemorrhage or intrathecal chemotx.

Front 2

How do you increase your sensitivity for finding leptomeningeal disease?

Back 2

- Look at the CISTERNAL SEGMENTS of CN5 and intracanalicular portion of CN 7 and 8.
- Normally, the cisternal portions of the cranial nerves do not enhance.

Front 3

1. What are the complications of meningiomas?
2. How do you differentiate among benign, atypical, and malignant meningioma?
3. How often are atypical features seen?

Back 3

1.
- VASOGENIC EDEMA in the brain.
- ENCASEMENT or NARROWING of arterial structures may lead to TIA or stroke.
- INVASION of adjacent DURAL SINUS may prevent complete resection.
- BLINDNESS caused by a parasellar or optic nerve sheath meningioma.
2. The various types of meningiomas appear identical on imaging. However, MALIGNANT MENINGIOMAS are more likely to demonstrate SIGNIFICANT BRAIN EDEMA and INVASION.
3. Atypical features of meningiomas are seen in 15% which include
- heterogeneous enhancement
- cyst formation
- hemorrhage
- fatty degeneration

Front 4

1. How do you differentiate between meningioma and dural mets?
2. What is a complication of dural mets?
3. What primary tumors metastasize to the dura?
4. Which primary tumors metastasize to the leptomeninges?

Back 4

1.
- Dural mets DO NOT demonstrate HYPEROSTOSIS
- Dural mets more often INVADE brain parenchyma and incite brain edema.
- Dural mets often show CONCURRENT CALVARIAL and brain PARENCHYMAL masses.
2. Subdural hematoma
3. Breast and prostate
4. Breast, lung, melanoma. Tumor cells reach the leptomeninges by several routes:
- hematogenous spread to small meningeal vessel
- hematogenous spread to the choroid plexus with shedding of tumor cells into the CSF.
- direct extension of peripheral parenchymal mets into the CSF space.

Front 5

1. What are the CNS manifestations of sarcoidosis?
2. What serum test is elevated in pts with sarcoidosis?
3. What can sarcoidosis be confused with?

Back 5

1.
- If dural involvement = chronic headaches
- If leptomenigneal involvement = cranial neuropathy
- If parenchymal involvement = seizures or focal neurological findings
- If infundibular involvement = diabetes insipidus
2. ACE level
3.
MENINGITIS:
- as sarcoidosis can also result in meningeal enhancement.
MENINGIOMA/DURAL METS:
- as sarcoidosis can also result in plaque-like thickening of the leptomeninges or masslike dural thickening.
- like meningioma, sarcoid granulomas are intrinsically dense and have homogeneous enhancement. However, sarcoid granulomas are HYPOINTENSE on T2WI.
INFUNDIBULAR HISTIOCYTOSIS:
PERIVENTRICULAR WHITE MATTER DZ:
- may have mass effect
- sarcoidosis results in a vasculitis which causes WM abnormalities.

Front 6

1. What is the etiology of intracranial hypotension?
2. What are the imaging findings of intracranial hypotension?

Back 6

1. Intracranial hypotension may be primary or secondary:
- Primary: 2/2 occult CSF leak mainly from spinal sources (perineural cyst).
- Secondary: lumbar puncture, severe dehydration resulting in inadequate CSF production.
2.
- "Brain sagging"
- Downward displacement of the cerebellar tonsils.
- Flattening of the pons against the dorsal clivus
- Draping of the optic chiasm over the sella.
- Prominence of venous sinuses
- Bilateral convexity subdural hematomas due to tearing of bridging veins from downward tension on the dura.
- Diffuse intense enhancement of the dura.

Front 7

What are the complications of infectious meningitis?

Back 7

- Communicating or non-communicating hydrocephalus 2/2 proteinaceous debris (pus) that plugs up the arachnoid villi.
- Ventriculitis
- Brain abscess
- Subdural or epidural empyema
- Ishemia/infarction 2/2 infectious vasculitis and venous thromboses

Front 8

1. What is superficial siderosis?
2. What are the clinical sxs?
3. What are the possible etiologies?
4. What are the imaging findings?

Back 8

1. Rare condition characterized by deposition of hemosiderin in the leptomeninges and on the surface of the inferior cerebral hemispheres.
2. Progressive bilateral hearing loss, ataxia.
3.
- Tumor related hemorrhages (spinal cord ependymoma)
- Vascular malformations
- Chronic subdural hematomas
4. Rim of hypointensity on T2WI on the surface of the brainstem, cerebellum, inferior cerebral hemispheres, and upper cervical cord.
- Hypointensity along CN 1, 2, and 8.
- Atrophy of vermis and cerebellar hemispheres
- Enhancement of thickened meninges.

Front 9

Pachymeningeal enhancement

Back 9

INTRACRANIAL HYPOTENSION
METASTASES
- breast, lung, prostate CA are most common causes
- hematologic malignancies (lymphoma and leukemia) may also demonstrate abnormal enhancement.
PACHYMENINGITIS:
- bacterial, fungal, viral
- also usually involves the leptomeninges
SUBDURAL HEMORRHAGE:
- blood within the subdural space can cause meningeal irritation which manifests as enhancement on MRI.
SARCOIDOSIS
- can cause both leptomeningeal and pachymeningeal enhancment.