Leptomeningeal enhancement refers to a diffuse or focal gyriform or serpentine enhancement that can be seen in the following conditions:
Diffuse
-
meningitis
- pyogenic meningitis
- viral meningitis
- tuberculous meningitis (can also be focal)
- CNS cryptococcal infection
- coccidioidal meningitis (can also be focal)
- primary amoebic meningoencephalitis
- encephalitis
- tumors
- primary
- secondary
- leptomeningeal carcinomatosis (e.g. from carcinoma of breast or lung, melanoma, ependymoma)
- meningeal melanomatosis
- hemorrhage (e.g. post-subarachnoid)
- post uncomplicated lumbar puncture (rare, less than 5%) 2
- granulomatous conditions
- neurosarcoidosis (can also be focal)
- post-operative (late finding)
- post-traumatic (late finding)
Focal
- leptomeningeal carcinomatosis (e.g. from carcinoma of breast or lung, melanoma)
- post-ictal hyperemia
- infarction: subjacent acute (leptomeningeal collaterals) or subacute
- lymphoma
- meningitis (e.g. tuberculous)
- encephalitis
- neurosarcoidosis
- postoperative scar
- vasculitis
- Sturge-Weber syndrome
Terminology
The enhancement of the brain surface is known as pial or pial-arachnoid enhancement and often referred to as leptomeningeal enhancement 3.
Conversely, as the thin arachnoid membrane is attached to the inner surface of the dura mater, the pachymeningeal pattern of enhancement can also be described as a dural-arachnoid enhancement 3.