Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Traumatic Intracranial Arterial Dissection


KEY FACTS

Terminology

  • Dissection

    • Intramural hematoma extends along vessel wall

  • Dissecting aneurysm

    • Dissection + aneurysmal dilation contained by adventitia

  • Pseudoaneurysm

    • Lumen contained by thrombus outside vessel wall

Imaging

  • Location

    • Often adjacent to falx, skull, tentorium, or region of significant motion

    • Posterior circulation most common

      • –

        Vertebral arteries most common site (72%)

      • –

        Extension into basilar artery rare

    • Anterior circulation uncommon

      • –

        Supraclinoid internal carotid artery

      • –

        Distal, more peripheral (A2, M2, P2, and beyond) where vessel contacts dura or skull

  • NECT: Basal subarachnoid hemorrhage (SAH)

    • Looks like aneurysmal SAH

    • In unusual locations, more extensive than traumatic SAH

  • MR: Hyperintense hematoma + central “flow void”

    • Target or crescent sign

    • SAH → sulcal/cisternal hyperintensity on FLAIR

  • CTA/MRA/DSA

    • “Fat” vessel (dissecting aneurysm or mural thrombus)

    • Long segment narrowing or tapered occlusion

    • Intraluminal flap (± on DSA/MRA; best seen on DSA)

    • ± dissecting aneurysm (irregular, wide neck; at side wall, usually not at vessel bifurcations)

Top Differential Diagnoses

  • Intracranial artery narrowing/occlusion

    • Atherosclerosis

    • Vasospasm

    • Vasculitis

  • Traumatic SAH

    • Aneurysmal, perimesencephalic nonaneurysmal SAH

Clinical Issues

  • May cause acute emboli

  • Rupture (dissecting aneurysm/pseudoaneurysm)

Axial NECT scan in a 29-year-old woman involved in a high-speed MVA shows subarachnoid hemorrhage (SAH)
surrounding the lower medulla.

More cephalad NECT scan in the same patient shows extensive SAH filling the basal cisterns, outlining the midbrain. Note the enlargement of the temporal horns
, indicating early extraventricular obstructive hydrocephalus.

Slightly oblique lateral DSA in the same patient shows focal fusiform enlargement of the left vertebral artery
, suggesting a dissecting pseudoaneurysm may be the etiology for the SAH.

Oblique 3D color-shaded surface display in the same patient shows the focal right dissecting aneurysm
as well as a 2nd dissecting aneurysm along the distal right vertebral artery
. The patient had a cardiac arrest after the DSA and expired.

TERMINOLOGY

Synonyms

  • Traumatic dissection and pseudoaneurysm

Definitions

  • Dissection: Intramural hematoma extends along vessel wall

  • Intimal extension

    • Intimal flap

    • True and false lumen

  • Arterial transection

    • Extension through adventitia

  • Dissecting aneurysm: Aneurysmal dilation of vessel due to dissection, contained only by adventitia

    • Hematoma between media/adventitia common

  • Pseudoaneurysm: Lumen contained only by thrombus outside vessel wall

IMAGING

General Features

  • Best diagnostic clue

    • NECT: Basal extensive subarachnoid hemorrhage (SAH) mimics aneurysmal SAH, but often more extensive than traumatic SAH or in unusual locations

    • MR: Hyperintense crescent in vessel wall with central or eccentric flow void on axial T1WI and T2WI (“target” or “crescent” sign)

      • –

        Subarachnoid hyperintensity on FLAIR due to hemorrhage

      • –

        Enlarged vessel due to dissecting aneurysm or mural thrombus

    • MRA, CTA, DSA

      • –

        Long segment narrowing or tapered occlusion

      • –

        Intraluminal flap on MRA/CTA source images

      • –

        ± irregular, eccentric side wall dissecting aneurysm

        • □

          Usually not at bifurcation

  • Location

    • Often occurs at contact points with falx, skull, tentorium, or at region of significant motion

    • Posterior circulation most common

      • –

        Vertebral arteries most common (72%)

      • –

        Posterior inferior cerebellar artery (PICA) occurs, but less common

      • –

        Extension into basilar artery rare

    • Anterior circulation uncommon

      • –

        Supraclinoid internal carotid artery

      • –

        Otherwise, more peripheral (A2, M2, P2, and beyond)

        • □

          Usually where vessel contacts dura or skull

  • Morphology

    • Tapered stenosis with occlusion

    • Irregular vessel narrowing

    • Fusiform irregular dilatation or focal dissecting aneurysm

    • Intimal flap and double (true and false) lumen

    • Intramural hematoma

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts