Optical Coherence Tomography of Spontaneous Basilar Artery Dissection in a Patient With Acute Ischemic Stroke

Abstract

The diagnosis of intracranial arterial dissection (IAD) may be challenging and multimodal imaging techniques are often needed to confirm the diagnosis. Previous studies have based their criteria for diagnosis of IAD on conventional angiography, computed tomography, or magnetic resonance imaging. We report a case with acute ischemic stroke due to spontaneous basilar artery dissection in which intravascular optical coherence tomography (OCT) was used to show features of IAD. A 59-years-old woman presented with symptoms of acute ischemic stroke. Thrombosis related to basilar artery (BA) stenosis was assumed on conventional angiography; however, no clot was retrieved after mechanical thrombectomy (MT) and a restored BA caliber was observed after a rescue recanalization with the detachment of a self-expanding stent was performed. Spontaneous IAD was suspected; however, angiographic findings were ambiguous for confirming IAD. The patient remained symptom-free until 18-months follow-up. At this point, angiography showed restenosis at the proximal tapered length of the stent. In vivo OCT was performed to assess the pathological changes of the restenosis and confirm the diagnosis of IAD.OCT revealed BA dissection with the presence of remnant transverse flap, double lumen and mural hematoma. Imaging at multiple levels identified intimal disruption that originated in the right vertebral artery and extended distally to the BA. The use of intravascular imaging with OCT enabled the accurate diagnosis of IAD. Care should be taken as the procedure may add additional risks to the patient. Future studies are needed to validate the safety of OCT in IAD.

Keywords: acute ischemic stroke; feasibility; imaging diagnosis; intravascular optical coherence tomography; safety; spontaneous intracranial arterial dissection.

Figure 1

Spontaneous basilar artery (BA) dissection causing acute ischemic stroke. Non-contrast CT (A). Anterior (B), and lateral (C) projection of angiography before stent deployment. There is a “non-occlusive thrombus” in the mid-BA with regular residual lumen (C). Intracranial atherosclerotic stenosis was then suspected (black arrow). The super -selective angiography control was performed to confirm the tip of the microcatheter in the real lumen (D). Angiography after the first mechanical thrombectomy maneuver (E). No clot was found. Angiography immediately after stent detachment showed the stent restored the BA caliber (F). The distal marker of the stent lined up with the BA tip whereas the proximal marker was located within the right vertebral artery. MRI in transverse DWI section showed acute infarctions in right pons (G) and occipital lobe (H) after procedure.

Figure 2

Proximal in-stent restenosis on 18-months follow-up angiography. Anterior (A,B) and lateral (C,D) view of subtracted (A,C) and un-subtracted angiography (B,D) in right VA demonstrated proximal stenosis within the tapered length of the stent construct. Oblique view of the angiography (E). Black and white arrow indicated proximal and distal markers of the stent, respectively.

Figure 3

oblique view from an un-subtracted angiography of the right vertebral artery shows right VA dissection extending to BA. The markers of the SOLITAIRE stent and the Dragonfly Duo OCT imaging catheter are noted in the left panel. White dashed ellipses on the left panel correspond to the cross-sections of the OCT acquisition (right). The Dragonfly Duo imaging catheter is illustrated in the middle. (A), the OCT image demonstrated a severe dissection (*), between the intima (single white arrow) and media (double white arrow). Poor strut-wall apposition was noted (struts indicated by the white arrowheads). (B), 10 mm proximal to the cross-section A, there was a mural hematoma (single white arrow) within the dissection. The intima was complete without disruption. The false lumen (*) between the intima and media (double white arrow) caused the moderate stenosis of the BA. (C), at the level of restenosis in right VA within the tapered area of the SOLITAIRE stent, there is a disrupted transverse flap (single white arrow) and mural hematoma, suggesting the dissection originated in right VA and extended distally to BA. (D), at the level of posterior inferior cerebral artery (PICA) origin, no dissection is visible on DSA or OCT. Single white arrow indicated PICA. The presence of remnant transverse flap, double lumen and mural hematoma were signs of intracranial BA dissection on OCT.