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Developmental Venous Anomaly (DVA)

Summary

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  • DVAs are congenital vascular malformations characterised by a radial arrangement of dilated medullary veins converging on a large collecting vein
  • Most common cerebral vascular malformation, typically asymptomatic and incidentally discovered on neuroimaging
  • Generally considered benign and do not require treatment, but may rarely be associated with other vascular malformations or haemorrhage

Pathophysiology

  • Result from arrested development of venous system during embryogenesis
  • Represent persistent embryonic medullary veins that failed to regress
  • Function as normal drainage pathways for brain parenchyma
  • Typically drain into deep or superficial venous systems

Demographics

  • Prevalence: 2.6% in autopsy series, up to 6.4% in MRI studies
  • No significant gender predilection
  • Can occur at any age, but most commonly diagnosed in adults

Diagnosis

  • Usually asymptomatic and discovered incidentally on imaging
  • Rarely associated with:
    • Headaches
    • Seizures
    • Focal neurological deficits
  • May coexist with other vascular malformations (e.g., cavernous malformations)

Imaging

  • CT:
    • Contrast-enhanced: "caput medusae" appearance of converging veins
    • Non-contrast: may show calcifications or associated cavernomas
  • MRI:
    • T1-weighted: flow void of draining vein
    • T2-weighted: hypointense radial veins
    • Susceptibility-weighted imaging (SWI): prominent veins
    • Post-contrast T1: enhancement of radial veins and draining vein
  • Angiography:
    • "Caput medusae" appearance in venous phase
    • Normal arterial phase

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  • Incidental findings of a dilated vein with the caput medusa sign.
  • The DVA was associated with a small cavernoma (red arrow) .

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  • Incidental finding of a flow void on all sequences with a wider caput medusae on the SWI minimum intensity projection.

Treatment

  • Generally, no treatment required for asymptomatic DVAs
  • Management focuses on associated conditions:
    • Cavernous malformations: may require surgical resection
    • Intracranial haemorrhage: conservative management or surgical intervention based on severity
  • Anticoagulation should be used cautiously in patients with DVAs
  • Surgical resection of DVAs is contraindicated due to risk of venous infarction

Differential diagnosis

Differential Diagnosis Differentiating Feature
Cavernous Malformation DVAs typically have a "caput medusae" appearance on contrast-enhanced imaging, while cavernous malformations have a popcorn-like appearance
Arteriovenous Malformation DVAs do not show arterial feeders or early venous drainage on angiography, unlike AVMs
Capillary Telangiectasia DVAs are larger and have a characteristic "umbrella" or "palm tree" appearance, while capillary telangiectasias are smaller and less organised
Dural Arteriovenous Fistula DVAs do not demonstrate arterial-venous shunting or cortical venous reflux seen in dAVFs
Cerebral Aneurysm DVAs do not show a saccular or fusiform dilatation of arteries, which is characteristic of aneurysms
Tumour (e.g., Glioma) DVAs do not enhance or show mass effect like tumours, and they follow blood signal on all sequences
Cerebral Abscess DVAs do not show restricted diffusion or ring enhancement typically seen in abscesses
Multiple Sclerosis Plaques DVAs do not show the typical ovoid, periventricular white matter lesions seen in MS
Cerebral Infarction DVAs do not show restricted diffusion or follow a vascular territory like acute infarcts
Cerebral Contusion DVAs do not show blooming artefact on susceptibility-weighted imaging or evolve over time like contusions