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Cross Cerebellar Diaschisis

Summary

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  • Functional depression of the contralateral cerebellar hemisphere following a supratentorial lesion
  • Characterised by reduced blood flow and metabolism in the cerebellar hemisphere opposite to a focal supratentorial lesion
  • Typically associated with stroke but can occur in other conditions affecting cerebral cortex or subcortical structures1

Mechanism

  • Disruption of the corticopontocerebellar pathway leads to deafferentation of the contralateral cerebellar hemisphere
  • Reduced excitatory input from the cerebral cortex results in decreased neuronal activity, blood flow and metabolism in the affected cerebellar hemisphere
  • Mediated by transneuronal metabolic depression rather than direct ischaemia

Imaging Appearance

  • Conventional CT and MRI:
    • Usually normal in the affected cerebellar hemisphere
    • Useful for identifying the primary supratentorial lesion
  • SPECT (Single Photon Emission Computed Tomography):
    • Gold standard for diagnosis
    • Shows decreased perfusion in the contralateral cerebellar hemisphere
  • PET (Positron Emission Tomography):
    • Demonstrates reduced glucose metabolism in the affected cerebellar hemisphere
  • CT perfusion:
    • May show decreased blood flow in the contralateral cerebellar hemisphere
  • MRI:
    • Arterial spin labeling (ASL) perfusion can demonstrate reduced cerebellar blood flow
    • Diffusion-weighted imaging (DWI) may show restricted diffusion in acute cases

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Clinical Relevance

  • Not a lesion in its own right and requires no specific treatment: recognising it avoids misinterpreting the cerebellar asymmetry as a separate lesion
  • Most commonly seen with acute ischaemic stroke, particularly in the middle cerebral artery territory, and with large hemispheric lesions or subcortical white matter and basal ganglia involvement
  • Also observed in traumatic brain injury, tumours and epilepsy
  • Usually clinically occult, as symptoms are masked by the primary supratentorial lesion; recognition therefore relies on functional neuroimaging

Differential diagnosis

Differential Diagnosis Differentiating Feature
Cerebellar infarction Restricted diffusion on DWI; does not cross midline
Posterior reversible encephalopathy syndrome (PRES) Bilateral involvement, often in parieto-occipital regions
Cerebellar tumour Mass effect, enhancement on contrast-enhanced MRI
Cerebellar abscess Ring-enhancing lesion with restricted diffusion
Wernicke encephalopathy Bilateral symmetrical involvement of mammillary bodies, thalami, and periaqueductal gray matter
Cerebellar atrophy Generalized volume loss, not unilateral
Multiple sclerosis Multiple white matter lesions, often ovoid and periventricular
Cerebellar contusion Associated haemorrhagic foci on GRE/SWI; overlying skull fracture or extracranial soft tissue swelling on CT
Metastatic disease Multiple lesions with surrounding oedema; ring or nodular enhancement; no ipsilateral supratentorial lesion
Spinocerebellar ataxia Bilateral symmetric cerebellar and brainstem atrophy; no corresponding supratentorial lesion

  1. M Reivich. Crossed cerebellar diaschisis. 1992. AJNR. American journal of neuroradiology - Open in new tab. ↩