Demonstration of intraluminal thrombus in the carotid artery by optical coherence tomography: technical case report

Intraluminal thrombus in the carotid artery is often misdiagnosed because clinical imaging, such as angiography and duplex ultrasonography, fails to accurately identify it. Recently, it was reported that optical coherence tomography (OCT), a new imaging modality, can visualize intravascular thrombus in the coronary artery.

An 83-year old male was admitted due to newly developed motor weakness of the left hand. Diffusion weighted magnetic resonance imaging showed multiple high intensity spots in the territory of the right middle cerebral artery, and magnetic resonance angiography revealed significant stenosis at the origin of the right internal carotid artery. Because of an apparent change in plaque shape on the angiogram just before carotid artery stenting, further examinations such as intravascular ultrasonography (IVUS) and OCT were performed.

After IVUS examination, both the common carotid and external carotid arteries were occluded by an occlusion balloon system prepared for carotid artery stenting. Then the stenotic site was imaged by OCT from the distal section at 1 mm/sec using a built-in pull-back system with continuous injection of saline through the guiding catheter to remove blood from the field of view. Since intraluminal thrombus was clearly demonstrated by an OCT, carotid endarterectomy was performed instead of stenting, and thrombus was confirmed by surgical specimen.

OCT may provide useful information for diagnosis of an intraluminal thrombus in the carotid artery, which is important for the appropriate selection of therapeutic strategy.