PMC8202360_01
Preoperative images. (a) Diffusion-weighted images showing scattered infarctions at the left subcortical watershed area. (b) Magnetic resonance angiography showing left internal carotid artery occlusion. (c) Right internal carotid artery angiogram showing blood flow to left side via anterior communicating artery and aneurysms at right internal carotid artery bifurcation and left middle cerebral artery bifurcation. (d) SPECT showing decreased accumulation in the left middle cerebral artery watershed area. (e) Arterial spin labeling magnetic resonance imaging indicating decreased cerebral blood flow in the left hemisphere. (f) T2-weighted magnetic resonance imaging showing more watershed infarctions in the left hemisphere than the right side
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F1
His head diffusion-weighted magnetic resonance imaging (MRI) revealed scattered infarctions at the left subcortical watershed area [Figure 1a], and MR angiography showed left ICA occlusion and aneurysms at the right ICA bifurcation [Figure 1b]. ICA occlusion from the cervical portion, and it was seen that the left cerebral hemisphere was supplied by cross-flow from the right side via the anterior communicating artery [Figure 1c]. In addition, there were aneurysms at right ICA and left MCA bifurcations, 22 and 4 mm in maximum diameter, respectively [Figure 1c]. 99mtechnetium ethylcysteinate dimer single-photon emission computed tomography showed decreased accumulation in the left MCA area [Figure 1d], and arterial spin labeling MR imaging (ASL-MRI) also indicated decreased cerebral blood flow in the left hemisphere [Figure 1e]. In addition, watershed infarctions were remarkably identified on the left hemisphere compared with the right side in T2-weighted MR imaging [T2-WI, Figure 1f]. Thus, hemodynamic impairment due to ICA occlusion was suggested on the left side.
Postoperative and follow-up images. (a) Postoperative digital subtraction angiography showing good patency of bypass. Follow-up study at 6 months after the operation. Magnetic resonance angiography showing robust bypass (b), revealing symmetrical cerebral blood flow (c), and T2-weighted magnetic resonance imaging demonstrating no new infarction (d)
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F2
Postoperative MR imaging demonstrated no new cerebral infarction and DSA revealed good patency of bypass [Figure 2a]. MR angiography demonstrated robust bypass flow, ASL-MRI indicated symmetrical cerebral blood flow, and T2-WI showed no new infarction [Figure 2b-d].