Neuro Metabolic Disease

Cerebral Amyloid Angiopathy

• Blooming black dots

• Seen in amyloid disease and chronic hypertensive encephalopathy

• May resemble chronic hypertensive encephalopathy on imaging

• Both will have blooming black dots

  • In cortex and pia —> amyloid

  • In basal ganglia and cerebellum —> HTN

• Superficial siderosis present

• Systemic siderosis does not correlate with CAA

Eye of the Tiger Sign

• Symmetric low T2 signal of globus pallidus (due to accumulation of iron) with central area of high signal (due to gliosis)

• Associated with PKAN (pantothenate kinase associated neurodegeneration)

• Other associations

  • Organophosphate poisoning

  • Parkinsonism

  • Wilson disease

Canavan Disease

• High NAA peak - caNAAvan disease

• Jews

• Deficiency of N-acetylaspartoacylase (i believe needed to break down NAA and therefore NAA accumulates and fucks shit up)

• Every picture I have seen is always that super bright white matter on the T2

Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS)

• Multifocal stroke like lesions in different stages of healing and does not follow a specific vascular territory

• Prefers posterior parietal and occipital lobes

• Seen < 40 yo

• Black toenail sign

Random Syndromes

PHACES

• Posterior fossa abnormality

• Hemangioma

• Arterial anomaly

• Cardiac defects

• Eye abnormality

• Sternal defects

Basal Ganglia

Bilateral Basal Ganglia

• T1 Bright basal ganglia

  • Liver failure

  • Hyperalimentation (manganese)

  • High blood sugar (non DKA)

  • Wilsons disease

• Viral infection (West Nile, Japanese Encephalitis)

• Drugs

  • Heroin

  • CO poisoning

  • Methanol

  • Cyanide

  • Niroimidazole

Methanol Poisoning

• Classically Symmetric Putamen hyperintensity

• Looks like orange slice candy

Nonspecific bilateral - typically symmetric basal ganglia involvement

• Cyanide

• Organophosphate poisoning

  • Typically lacks hemorrhage which may be seen with others

Wilson’s Disease

• Autosomal recessive disorder of copper metabolism

• Increased signal in bilateral putamen is most common CNS finding

• Can occur pretty much every where else, midbrain seems to also be important though

• Multiple key signs associated with this:

  • Panda face = involvement of white matter surrounding red nuclei make the nuclei prominent and look like eyes

  • Claustra sign - hyperintensity in the claustra (linear area between external capsule medially and insula laterally)

Metachromatic Adrenoleukodystrophy

• Lack of Arylsulfate A results in accumulation of galactosylsulfatide

• Lysosomal disorder

• Failure to break down and re-utilize myelin

• Autosomal recessive

• Stripes of affected white matter inter-mixed with unaffected white matter resulting in tigroid appearance

Non-Ketotic Hyperglycemia Hemichorea

• Bright putamen

• Sometimes has accompanying bright caudate and globus pallidus

• Bright on T1 - NOT A BLEED even if they have HTN with it

• Movement issues will be on opposite side of the side that has the abnormal imaging findings

Bilateral Thalami Involvement

• Wernickie

• Artery of Percheron infarct

• Internal cerebral vein thrombosis

Wernickie Encephalopathy

• Caused by thiamine deficiency typically in alcoholics

• Findings

  • T2/FLAIR hyperintensity of the bilateral thalami and periaqueductal gray matter

  • Mammillary body enhancement

CADASIL

• Recurrent infarcts in young to middle aged adults in absence of typical vascular risk factors

• Migraine typical early clinical presentation

• Mutation in NOTCH3 gene

• Basically diffuse FLAIR signal, frontal and anterior temporal lobe predominance

Hypertrophic Olivary Degeneration

• Basically lesion in the triangle of Guillian & Mollaret results in insult to the nerve tracts that run through there

  • This results in hypertrophy of the inferior olivary nucleus

  • Triangle is formed by the red nucleus, contralateral dentate nucleus and inferior olivary nucleus

• Classically presents with oculopalatal tremor (ocular, palate and msk tremors)

• Note that the inferior olivary nucleus is bound by the pre-olivary sulcus anteriorly and retro-olivary sulcus posterior-laterally

Autoimmune Encephalitis (sometimes called autoimmune limbic encephalitis)

• Basically FLAIR hyperintensity in the temporal and frontal lobes including insula

  • No restriction

  • No hemorrhage

  • May have some patchy enhancement

• Comes in two flavors, Neoplastic & Non-neoplastic

• Non-Neoplastic

  • Anti-GAD Abs

• Neoplastic

  • Anti Hu Abs - limbic encephalitis - associated with small cell lung cancer

  • Anti-Yo

  • Anti-Ri Abs

References:

• Case courtesy of Yune Kwong, Radiopaedia.org, rID: 41008

• Case courtesy of Elshan Abdullayev, Radiopaedia.org, rID: 50288