Miscellaneous Vasculitis

KEY FACTS

Terminology

• Heterogeneous group of CNS disorders

  • Characterized by nonatheromatous inflammation and necrosis of blood vessel walls

  • Both arteries, veins may be affected

Imaging

• CTA/MRA useful screening; spatial resolution usually insufficient for subtle disease

• MR

  • Basal ganglia, cortex, subcortical white matter

    • –

      Multifocal hypodensities/T2 hyperintensities

    • –

      Look for secondary signs (ischemia/infarction)

  • High-resolution (3T, thin-section) T1 C+ may demonstrate wall enhancement

    • –

      Smooth, concentric

    • –

      Long segment

    • –

      Distal involvement (e.g., M2, M3, M4 branches > intracranial internal carotid artery and basilar artery)

    • –

      Multiple vessels usually affected

• DSA

  • Findings nonspecific (visualizes lumen, not vessel wall)

    • –

      Multifocal areas of smooth or slightly irregular-shaped stenoses alternating with dilated segments

    • –

      May occur in intracranial vessels of any size

    • –

      Major differential diagnosis = intracranial atherosclerosis

Top Differential Diagnoses

• Intracranial atherosclerotic vascular disease

• Arterial vasospasm

• Reversible cerebral vasoconstriction syndrome

Pathology

• Vessel wall inflammation, necrosis common to all vasculitides

  • Bacterial, tuberculous meningitis

  • Mycotic, viral, syphilitic, granulomatous arteritis

  • Cell-mediated, collagen-vascular arteritides

  • Drug abuse

Clinical Issues

• Thinking vasculitis?

  • Brain neuroimaging is only beginning

  • Add toxicology screen, lumbar puncture, angiography

  • Only biopsy allows definite diagnosis

TERMINOLOGY

IMAGING