KEY FACTS Terminology Diaschisis = sudden loss of function in brain connected to (but at distance from) damaged area Crossed cerebellar diaschisis (CCD) = decreased blood flow/metabolism in cerebellar hemisphere contralateral to supratentorial infarct Imaging Acute: CT/MR perfusion shows ↓…
KEY FACTS Terminology Spinocerebellar ataxias (SCAs) Spinocerebellar atrophy; spinocerebellar degeneration Previously known as Marie ataxia, inherited olivopontocerebellar atrophy, spinocerebellar degeneration Inherited progressive neurodegenerative disorders Clinically, genetically very heterogeneous (> 60 types) – SCA 3 most frequent subtypes 2 groups: Autosomal…
KEY FACTS Terminology Wallerian degeneration (WaD) Secondary anterograde degeneration of axons and their myelin sheaths caused by interruption of the axonal integrity or damage to neuron Imaging Primary lesion is cortical or subcortical with WaD in descending white matter tracts…
KEY FACTS Terminology Amyotrophic lateral sclerosis (ALS) Selective degeneration of somatic motor neurons of brainstem/spinal cord and large pyramidal neurons of motor cortex Eventual loss of corticospinal tract (CST) fibers Imaging Small percentage demonstrate CST hyperintensity As CST is normally…
KEY FACTS Terminology Neurodegenerative disease characterized by supranuclear palsy, postural instability, mild dementia Imaging Midbrain atrophy (penguin or hummingbird sign) Sagittal T1WI shows concave/flat upper border of midbrain (normally convex) Axial T1WIs show abnormal concavity of lateral margins of midbrain…
KEY FACTS Terminology Corticobasal degeneration Progressive neurodegenerative disease Presents with cognitive dysfunction, “asymmetrical” parkinsonism Imaging Severe focal asymmetric cortical atrophy Perirolandic (posterior frontal, parietal cortex) Relative sparing of temporal, occipital regions ↑ signal intensity in frontal &/or parietal subcortical white…
KEY FACTS Terminology Posterior cortical atrophy (PCA) Rare neurodegenerative disorder of posterior cerebral cortex/connecting white matter (WM) Considered subtype of Alzheimer disease (AD) Results in impairment of ventral, dorsal visual perception pathways Typically precedes memory, executive impairment Imaging Sagittal T1WI,…
KEY FACTS Terminology Adult-onset fatal neurodegenerative disease Multiple system atrophy (MSA) has 3 clinical subtypes Cerebellar (MSA-C) Sporadic olivopontocerebellar (OPCA) atrophy Extrapyramidal (MSA-P) Parkinson subtype Striatonigral degeneration Autonomic (MSA-A) Shy-Drager syndrome Imaging General findings ↓ (“flat”) pons/medulla Cerebellar vermis/hemispheres atrophic…
KEY FACTS Terminology Parkinson disease (PD) Progressive neurodegenerative disease Primarily affects pars compacta of substantia nigra (SNpc) Imaging MR SNpc narrowed/inapparent (T2WI) SNpc progressively loses normal hyperintensity (from lateral to medial) Border between SNpc, red nucleus blurred in PD ↑…
KEY FACTS Terminology Important clinicopathologic Creutzfeldt-Jakob disease (CJD) variants Heidenhain variant CJD – Visual variant of CJD – Early isolated visual symptoms Brownell-Oppenheimer variant (rare) – Pure cerebellar syndrome Imaging FLAIR Subtle cortical hyperintensity in occipital lobes (“cortical ribbon”) Basal…