4.1 Case Presentation

4.1.2 Imaging Findings and Impression

Axial CT scans of the head without contrast (▶ Fig. 4.1a,b) show hyperdensities (HU of 110) involving the bilateral basal ganglia and the bilateral dentate nuclei (black arrows). Axial gradient-echo images (▶ Fig. 4.1c,d) show susceptibility artifact in the corresponding areas consistent with calcification (white arrows). The calcifications are symmetric without associated edema or mass effect.

4.2 Differential Diagnosis

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  Basal ganglia calcification:

  
  
  
  
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    Bilateral calcification involving the basal ganglia with a predominance for globus pallidus interna seen as hyperdensity on CT and presence of susceptibility on gradient-echo images.

  
  
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  Fahr’s syndrome:

  
  
  
  
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    Rare genetic disorder of abnormal vascular calcium deposition.

    
    
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    Presents as symmetrical calcifications of the bilateral globus pallidus, caudate, lentiform nucleus, thalamus, and dentate nucleus.

    
    
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    MR images may be normal or have hyperintense signal on the T1-weighted images.

    
    
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    PET scan may show degrees of fluorodeoxyglucose (FDG) uptake.

    
    
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    Should be differentiated from underlying metabolic causes such as hyperparathyroidism and hypoparathyroidism by measuring serum calcium, phosphorus, and alkaline phosphatase levels.

  
  
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  Mineralizing microangiopathy:

  
  
  
  
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    Usually seen in children receiving chemotherapy or radiotherapy.

    
    
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    Areas typically involved are the gray–white matter interface, lentiform nucleus, and dentate nucleus of the cerebellum.

  
  
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  Mitochondrial encephalomyopathy, lactic acidemia, and stroke-like symptoms (MELAS):

  
  
  
  
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    MELAS is a mitochondrial disease with maternal inheritance.

    
    
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    Presents in younger adults with multiple strokes in different stages of development, not confining to a specific vascular territory.

    
    
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    May show symmetric basal ganglia calcification. ^{2 , 3}

  
  
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  CNS tuberculosis:

  
  
  
  
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    Multiple punctate calcified and noncalcified lesions involving bilateral cerebral hemispheres, including the basal ganglia.

    
    
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    Since the noncalcified lesions are active granulomas, they tend to enhance with gadolinium administration.

  
  
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  Cockayne’s syndrome:

  
  
  
  
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    Rare genetic dysmyelinating disorder. Patients are children with neurodevelopmental delay and hearing and skin problems.

    
    
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    On brain MR images, there is atrophy of cerebellum, corpus callosum, brain stem, and supratentorial white matter.

  
  
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  TORCH (toxoplasmosis, other [syphilis, varicella-zoster, parvovirus B19], rubella, cytomegalovirus, and herpes) infection.

  
  
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  Congenital HIV infection and HIV encephalopathy may have basal ganglia calcifications which are NOT seen when the virus infection occurs later in life.