Unusual hemodynamic stroke related to an accessory middle cerebral artery: The usefulness of fusion images from three-dimensional angiography
A 77-year-old female experienced repeated TIAs of motor aphasia and dysarthria. On admission, she was alert and well oriented. She had no cranial nerve deficits or focal neurological signs. Magnetic resonance (MR) imaging revealed no evidence of acute cerebral infarction []. MR angiography showed an occlusion of the left internal carotid artery (ICA) and stenosis of the right MCA [Figure and ]. Some anomalous arteries were also identified faintly on MR angiography and ordinary angiography, but the detailed anatomy was not clear. Fusion images of three-dimensional digital subtraction angiography (3D-DSA) demonstrated an occlusion of the cervical portion of the left ICA and stenosis of both the proximal segments (M1) of the MCA []. In addition, a left AMCA, originating from near the anterior communicating artery (ACoA), was identified [Figures and ].\nThree-dimensional DSA revealed the characteristic cerebral blood flow (CBF) supply pattern. The AMCA supplied CBF to the frontal lobe alone. The AMCA was perfused by the right ICA via the ACoA. In addition, the left MCA, which was perfused by the left posterior cerebral artery via the left posterior communicating artery, supplied CBF to the temporal and parietal lobes [Figures -]. Because the proximal segment (A1) of the left ACA was occluded, the flows of the AMCA and MCA were clearly separate []. Single-photon emission computed tomography (SPECT) showed a marked decline in the CBF to the left fronto-temporo-parietal lesion at rest, while cerebral vascular reactivity was impaired by acetazolamide loading []. After diagnosis, we started antiplatelet medication (ASA 100 mg/day) and it continued until bypass surgery.\nIt was concluded that bypass surgery was needed for the territory of both the AMCA and MCA. A double anastomosis was performed that consisted of: (1) the frontal branch of the left superficial temporal artery (STA) to the cortical artery of the left AMCA; and (2) the parietal branch of the STA to the cortical branch of the left MCA. Prior to anastomosis, intraoperative indocyanine green video angiography was performed and demonstrated bidirectional flow in the left frontal cortical artery []. After anastomosis, the flow in the frontal cortical artery improved. A remarkable improvement in CBF in all lesions was confirmed postoperatively. The patient was discharged with no neurological deficits and remained free from ischemic attacks without antiplatelet medication for at least 1 year.