KEY FACTS Terminology ↓ overall brain volume with advancing age Reflected in relative ↑ cerebrospinal fluid spaces Imaging Broad spectrum of “normal” on imaging in elderly patients “Successfully aging brain” Smooth, thin, periventricular, high signal rim on FLAIR is normal…
KEY FACTS Terminology Sudden memory loss without other signs of cognitive or neurologic impairment; usually resolves within 24 h Imaging NECT, CECT almost invariably normal MR T2/FLAIR usually normal DWI: Focal dot-like area of diffusion restriction in hippocampus – Single…
KEY FACTS Terminology Status epilepticus: > 30 minutes of continuous seizures (SZs) or ≥ 2 SZs without full recovery of consciousness between seizures Synonyms: Transient seizure-related MR changes, reversible postictal cerebral edema Imaging Best diagnostic clue: T2 hyperintensity in gray…
KEY FACTS Terminology Seizure-associated neuronal loss and gliosis in hippocampus and adjacent structures Imaging Primary features: Abnormal T2 hyperintensity, hippocampal volume loss/atrophy, obscuration of internal architecture Secondary signs: Ipsilateral fornix and mammillary body atrophy, enlarged ipsilateral temporal horn, and choroidal…
KEY FACTS Terminology Osmotic demyelination syndrome (ODS) Formerly called central pontine myelinolysis (CPM) &/or extrapontine myelinolysis (EPM) Acute demyelination from rapid shifts in serum osmolality Classic setting: Rapid correction of hyponatremia ODS may occur in normonatremic patients Imaging Central pons…
KEY FACTS Terminology Many drugs (prescription, illicit, or street) have adverse CNS effects Illicit drug use often causes cerebrovascular disease Amphetamines, cocaine > opioids, cannabis Polydrug abuse (including EtOH) is common Nitrous oxide (NO₂) abuse → vitamin B12 inactivation →…
KEY FACTS Terminology Anoxic-ischemic encephalopathy, usually with bilateral lesions, caused by inhalation of carbon monoxide (CO) gas Imaging Best diagnostic clue: Globi pallidi (GP) T2/FLAIR hyperintensity T1 MR: Both hypointensity in GP (likely necrosis) and hyperintensity in GP (likely hemorrhage)…
KEY FACTS Terminology Idiopathic intracranial hypertension (IIH) Pseudotumor cerebri “Benign intracranial hypertension” ↑ intracranial pressure (ICP) without identifiable cause Imaging Empty or partially empty sella Posterior globe flattening Intraocular protrusion of optic nerve head Optic nerve sheath enlargement: Widened ring…
KEY FACTS Terminology Subcortical arteriosclerotic encephalopathy Imaging General features Lacunae (lenticular nuclei, pons, thalamus, internal capsule, caudate) Cerebral hemorrhage (basal ganglia/external capsule, thalamus) Confluent white matter (WM) disease (centrum semiovale, corona radiata) CT Diffuse WM hypodensity on CT Lacunar infarcts…
KEY FACTS Terminology Cerebrovascular autoregulatory disorder Many etiologies with HTN as common component Preeclampsia, eclampsia Drug toxicity (e.g., chemotherapy) Uremic encephalopathies Imaging General Patchy parietooccipital cortical/subcortical edema in patient with severe acute/subacute HTN CT Bilateral nonconfluent hypodense foci ± symmetric…