Neuro -- Misc

DDX of high T1 and T2 lesion:
- Craniopharyngioma
- Chronic hemorrhagic lesion
- Dermoid
- Cholesterol cyst or granuloma
- Rathke’s cleft cyst

Growing fractures occur when there is a skull fracture that leads to disruption of the dura allowing arachnoid to herniate in between the fracture forming a leptomeningeal cyst.

1. Lying Lazy No Good Crooks Collected My Insurance.
- Lipid: Product of brain destruction
- Lactate: Product of anaerobic glycolysis
- NAA: neuronal marker; decreases with any disease that adversely affects neuronal integrity.
- Glutamate:
- Creatine: energy metabolism
- Choline: cell membrane turnover. Elevated in tumors and inflammatory processes
- Myoinositol: glial cell marker

2.
- Lipid, lactate: around 1ppm
- NAA: around 2ppm
- Creatinine, Choline: around 3pmm

3. Hunter's angle is the line formed by the metabolites (line connecting the choline, creatinine, and NAA peaks). NAA should be the highest peak and the creatinine should be higher than choline.

NAA/Cr:
- Normal > 2
- Abnormal < 1.6

NAA/Cho
- Normal > 1.6
- Abnormal < 1.2

Cho/Cr
- Normal < 1.2
- Abnormal < 1.5

http://spinwarp.ucsd.edu/neuroweb/Text/mrs-TXT.htm

Look for abnormal shape of the ventricles which appear angulated.
The ventricles are dilated.
Volume of white matter is decreased
Premature birth
Periventricular gliosis that does not enhance.

Treated with embolization

- Herpes Encephalitis
- Ischemia/infarction
- Gliomatosis cerebri
- Limbic encephalitis: paraneoplastic syndrome associated with a primary malignancy (lung or breast). Imaging findings may be indistinguishable from herpes encephalitis, however, onset of symptoms is more insidious.
- Status epilepticus: seizures result in disruption of the blood-brain barrier with hyperperfusion.

VIRCHOW-ROBIN SPACES:
- pial lined fluid filled structures that accompany penetrating arteries.
- do not communicate with the subarachnoid space (think of them as peribiliary cysts)
- follow CSF SI on all sequences
- MC location = basal ganglia/anterior commissure. Also seen in deep white matter, midbrain, subinsular cortex.
- giant VR spaces occur in the midbrain and cause mass effect upon the 3rd ventricle and cerebral aqueduct.
LACUNAR INFARCT
- Small, well-circumscribed areas of encephalomalacia
- typically located in basal ganglia, thalami, internal capsules, and pons
- mimic VR spaces. Look for gliotic white matter surrounding the lesions to differentiate
- associated with small vessel ischemic disease.
INFECTION
- Neurocysticercosis
- Cryptococcosis
CYSTIC NEOPLASM
- JPA
- PXA
- Ganglioglioma
NEUROGLIAL CYST
- non-enhanicng parenchymal cyst.

- Neoplasms = metastatic disease, lymphoma, astrocytoma, ependymoma, PNET.
- Infection: tuberculoma, cryptococcoma
- Inflammatory = Tumefactive MS, sarcoid granuloma.

- Dyke Davidoff Masson syndrome
- Shunted hydrocephalus
- Hyperparathyroidsm
- Acromegly
- Osteopetrosis