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Arterial Dissection

Summary

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  • Arterial dissection is characterised by a tear in the intimal layer of an artery, allowing blood to enter the vessel wall and create a false lumen
  • Common locations include carotid, vertebral, and aortic arteries
  • Imaging plays a crucial role in diagnosis and management1

Pathophysiology

  • Intimal tear allows blood to enter the media, creating a false lumen
  • Propagation of dissection can lead to:
    • Luminal narrowing or occlusion
    • Aneurysmal dilatation
    • Rupture
  • Mechanisms:
    • Spontaneous (e.g., connective tissue disorders)
    • Traumatic (e.g., blunt or penetrating injury)
    • Iatrogenic (e.g., catheterization procedures)

Demographics

  • Incidence: 2.6-3.0 per 100,000 person-years for carotid dissection
  • Age: Peak incidence in 40-50 years old
  • Gender: Slight male predominance
  • Risk factors:
    • Hypertension
    • Smoking
    • Connective tissue disorders (e.g., Marfan syndrome, Ehlers-Danlos syndrome)
    • Recent trauma or chiropractic manipulation

Diagnosis

  • Clinical presentation:
    • Headache or neck pain
    • Neurological deficits (e.g., TIA, stroke)
    • Horner's syndrome (in carotid dissection)
  • Laboratory tests:
    • D-dimer (elevated in acute dissection)
  • Imaging:
    • Essential for definitive diagnosis

Imaging

  • CTA (first-line): tapered ("flame-shaped") stenosis or occlusion, intimal flap, double lumen, mural thrombus and any pseudoaneurysm
  • MRI/MRA: the crescentic T1-hyperintense intramural haematoma on fat-saturated T1 is the most specific sign (subacute methaemoglobin); may show associated infarcts on DWI
  • Ultrasound has a limited, mainly follow-up, role

panels-1

  • Patient presented with a right sided Horner's syndrome after a falling of bicycle.
  • NCCT showed an expanded right ICA jus below the skull base with a hyperdense rim.
  • The lumen was not narrowed on CTA.
  • T1-weighted imaging showed a crescent of high signal representing intramural haematoma.

panels-1 panels-2

  • 50-year-old patient presented with sudden onset right sided neck pain and a Horner's syndrome (blurred vision, right sided miosis and ptosis).
  • The initial CT and CTA showed a hyperdense rim around an expanded right ICA below the skull base without a significant stenosis (yellow arrow).
  • The T1-weighted imaging showed a T1-hyperintense rim around the ICA (red arrow).
  • The mural thrombus also showed diffusion restriction (blue arrow) and blooming on SWI (not shown).

Treatment

  • Antiplatelet or anticoagulation to prevent thromboembolic stroke
  • Endovascular stenting/embolisation for flow-limiting dissection or symptomatic pseudoaneurysm
  • Follow-up CTA/MRA at 3–6 months

Differential diagnosis

Differential Diagnosis Differentiating Feature
Atherosclerotic disease Gradual onset, risk factors present, no intimal flap on imaging
Aneurysm Focal dilatation, no intimal flap, often asymptomatic
Vasculitis Vessel wall thickening and enhancement on high-resolution MRI; no crescentic intramural haematoma; multifocal involvement
Fibromuscular dysplasia Beaded "string of beads" appearance on angiography; no intramural haematoma on fat-saturated T1
Spontaneous intramural haematoma Circumferential rather than eccentric wall thickening; no double lumen or intimal flap
Thromboembolism No intramural haematoma on T1 fat-saturated; intraluminal filling defect rather than mural thickening
Pseudoaneurysm Saccular outpouching at vessel wall; no crescentic T1 intramural signal

  1. Nash et al. Craniocervical Arterial Dissection in Children: Pathophysiology and Management. 2019. Pediatric neurology - Open in new tab. ↩