Unusual hemodynamic stroke related to an accessory middle cerebral artery: The usefulness of fusion images from three-dimensional angiography

Abstract

Background: Ischemic stroke associated with an anomaly of the middle cerebral artery (MCA) is a rare occurrence. The diagnosis is very difficult when there are steno-occlusive lesions associated with an accessory middle cerebral artery (AMCA).

Case description: A 77-year-old female with hypertension and hyperlipidemia experienced repeated transient ischemic attacks (TIAs) of motor aphasia and dysarthria. Although angiography showed only left intracranial occlusion, the fusion images of three-dimensional digital subtraction angiography (3-D DSA) showed complex steno-occlusive lesions and an AMCA related with the TIA. The cerebral blood flow (CBF) to the left frontal lobe was supplied by the AMCA, via the anterior communicating artery from the right internal carotid artery. The left temporal and parietal lobes were supplied by the stenotic MCA, via the left posterior communicating artery from the left posterior cerebral artery. Single-photon emission computed tomography showed a marked decrease in CBF to both the left frontal and temporal lobes. A left superficial temporal artery (STA)-to-left MCA double anastomosis was performed, in which each branch of the STA supplied branches of the AMCA and MCA.

Conclusion: This is the first reported case of ischemic stroke in a patient with an AMCA. The exact diagnosis could be made only by using fusion images of 3-D DSA, which were useful for understanding the complicated CBF pattern and for the choice of recipient artery in bypass surgery.

Keywords: 3D-DSA; Accessory middle cerebral artery; revascularisation; transient ischemic attack.

Figure 1

Magnetic resonance (MR) imaging on admission showed no acute infarction (a) T2WI, T2-weighted images; DWI, diffusion weighted images. MR angiography showed an occlusion of the left internal carotid artery (b and c, arrow) and stenosis of the bilateral middle cerebral artery (arrowhead). Some anomalous arteries were also suspected (b), but the detailed anatomy was unclear

Figure 2

Conventional angiography of the right internal carotid artery (a and b) and left vertebral artery (c and d). Anterior-to-posterior view (a and c) and lateral view (b and d). The arrow (c) indicates stenosis of the left proximal segment (M1) of the middle cerebral artery (MCA), which is supplied via the left posterior communicating artery. Note that the left accessory MCA supplied only the left frontal lobe (arrowhead in a and b), while the left MCA supplied the area beneath the Sylvian fissure (arrowheads in c and d)

Figure 3

Fusion images of three-dimensional angiography of the right internal carotid artery (brown) and left vertebral artery (red). To clearly illustrate the distal part of the middle cerebral artery (MCA), the right side of all images was intentionally eliminated. The left accessory MCA and left MCA run independently, and the areas they supply are clearly distinguished. The arrowhead (b) indicates the site of occlusion of the left anterior cerebral artery. The stenosis of the left MCA is indicated by the arrow (d)

Figure 4

Schematic drawing of the anomalous arteries and steno-occlusive changes found in this patient, showing the blood flow in the right internal carotid artery angiography (b) and the left vertebral artery angiography (c) as seen on Figures 2 and 3

Figure 5

Single-photon emission computed tomography showed a marked decline in cerebral blood flow at the left fronto-temporo-parietal lesion, and cerebral vascular reactivity was impaired by acetazolamide loading

Figure 6

The intraoperative findings (a and b) of the left superficial temporal artery-to-middle cerebral artery double anastomosis and magnetic resonance angiography after operation (c). Intraoperative indocyanine green video angiography showed the time delay of blood flow and bidirectional flow. The arrows indicate the anastomosis sites (a and b)