Internal carotid artery dissection

Case contributed by Antonio Rodrigues de Aguiar Neto

Presentation

Rescuers brought this patient to the emergency room, a victim of beatings. She presented with left hemiparesis of brachial predominance.

Patient Data

Age: 25 years
Gender: Female

Cranial non-enhanced computed tomography (NECT) and contrast-enhanced computed tomography (CECT) show patchy low-density areas on both cerebral hemispheres, representing ischemic strokes. There is a crescent-shaped hyperattenuating focus on the right internal carotid arteries (ICAs), representing intramural hematomas, with an intimal flap and double-lumen; Occlusion of the left ICA is hyperdense on NECT and do not opacify on CECT, corresponding to an intraluminal thrombus. 

Impression: These findings favored bilateral dissections of ICAs.

Magnetic resonance imaging (MRI) reveals focal cortical/subcortical areas of mild T1 hypointensity and high T2/FLAIR signal intensity scattered through both cerebral hemispheres, keeping with ischemic injuries, where some cortical laminar necrosis are also present and characterized by intrinsic high T1 signal. The largest region of the infarct is in the right frontoparietal lobe. The crescentic high signal on T1 and T2 around the right ICA correspond to subacute intramural hematomas in the false lumen, separated from the true lumen by a curvilinear intimal flap. Note left ICA loss of signal void on T2, representing occlusion due to luminal thrombus. 

Impression: These findings are consistent with bilateral dissection of both ICAs.

Digital subtraction angiography (DSA) demonstrates stenosis of the proximal right internal carotid artery shortly after the carotid bifurcation, followed by parietal irregularities extending from the cervical portion to the petrous segment – grade II injury. DSA also reveals an occluded left internal carotid artery after the carotid bulb without intracranial opacification – grade IV injury. Collateral refilling of the left middle cerebral artery via vertebrobasilar / circle of Willis. 

Impression: Angiogram confirms the diagnosis of bilateral ICAs dissection.

Case Discussion

Internal carotid artery dissection is a tear of the intima layer, allowing blood to collect in the media or the adventitia layer 1-4. The condition is a cause of stroke, particularly in young adults 1-4. CT and MR imaging studies may improve the diagnostic specificity for vessel wall injuries 2,3. Radiologists can recognize features of arterial dissection, so that appropriate diagnosis and management can start promptly, reducing the risks of ischemic stroke 1-3.

This case demonstrates imaging features of bilateral internal carotid dissection with cerebral strokes, probably due to blunt cerebrovascular injuries.

Case courtesy of

  • Rennah Gonçalves, MD - PGY-3, radiology resident, Department of Radiology
  • Luziany Carvalho Araújo, MD – radiologist, Department of Radiology
  • Antonio Rodrigues de Aguiar Neto, MD - radiologist, Department of Radiology

Hospital da Restauração – Recife, PE – Brazil

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