PMC8769467_01
Preoperative brain MR imaging, MRA, and CBF findings. (A) Time-of-flight MR angiography showed bilateral stenosis in the arteries centered on the terminal portion of the intracranial internal carotid arteries, including anterior cerebral arteries (A1 segment) and right MCA, which indicated typical MMD. The signal of peripheral MCA was markedly decreased, and only a faint vascular shadow of Sylvian vein and middle meningeal artery were evident. (B) Fluid-attenuated inversion-recovery imaging demonstrated cortical SAH in the right frontal cortical sulci when the patient developed severe headache and grand mal seizure. (C) N-isopropyl-p-[123I] iodoamphetamine-SPECT showed decreased cerebral blood flow in the right cerebral hemisphere, especially in the frontal lobe cortex. CBF: cerebral blood flow, MCA: middle cerebral artery, MMD: moyamoya disease, MR: magnetic resonance, MRA: magnetic resonance angiography, SAH: subarachnoid hemorrhage, SPECT: single photon emission computed tomography.
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F1
She was brought to a local hospital, diagnosed with subarachnoid hemorrhage (SAH) by magnetic resonance imaging, and suspected of having MMD by magnetic resonance angiography (MRA) (Fig. 1A and 1B). N-isopropyl-p-[123I] iodoamphetamine-single photon emission computed tomography (123I-IMP-SPECT) revealed cerebral blood flow (CBF) reduction in the right hemisphere (Fig. 1C).
Catheter angiography before the revascularization surgery. (A) Anterior-posterior and (B) lateral views on right ICA angiography demonstrated arterial narrowing in the arteries centered on the terminal portion of the intracranial ICA with intensification of the basal moyamoya vessels. Sprouting angiogenesis was observed at the periphery of the middle and posterior cerebral artery boundary (B). Neither major nor peripheral arterial aneurysm was observed. Arterial (B), capillary (C), and venous phase (D) of angiography showed no arteriovenous shunt in the frontal lobe. ICA: internal carotid artery.
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F2
These findings were observed bilaterally and were notable in the right hemisphere (Fig. 2A and 2B). There was no arteriovenous malformation (AVM) or fistula by catheter angiography before surgery (Fig. 2A-2D).
Intraoperative photographs during STA-MCA anastomosis. (A) The brain surface view of the right frontal lobe before the anastomosis showed dilated pial arteries, cloudiness of the arachnoid membrane, and xanthochromic spots in the cortical sulci, indicating hemosiderin deposits due to prior SAH. (B) Right after the STA-MCA anastomosis, fine cortical veins (black arrowheads) next to the site of anastomosis (dotted circle) turned arterial reddish in color. A part of the downstream superficial Sylvian vein (white arrows) also turned reddish, which indicated earlier arterial blood filling to the vein. (C) An earlier arterial phase of ICG video angiography demonstrated that arterial blood flow first came into the site of anastomosis (dotted circle) and toward the recipient MCA via the donor STA. (D) Subsequently, still in the early arterial phase, fluorescent ICG signal appeared in the fine cortical veins (black arrowheads), indicating earlier arterial blood filling to the vein. (E) In the latter arterial phase, early arterial blood filling near the site of anastomosis became more prominent (black arrowheads) and the laminar ICG signal flow was in part of the downstream superficial Sylvian vein (white arrows). ICG: indocyanine green, MCA: middle cerebral artery, SAH: subarachnoid hemorrhage, STA: superior temporal artery.
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F3
The brain surface, arteries, and veins were typical of MMD, as shown in Fig. 3A. A cortical branch of the right MCA on frontal lobe was thought to be ideal as the anastomosis recipient based on its diameter and color tone (Fig. 3A). Anastomosis was confirmed patent without blood leakage from the seam, and there were no microscopic blood clots inside (dotted circle in Fig. 3B). However, some veins were red in color, reflecting inappropriate arterial blood inflow (black arrowheads in Fig. 3B), in contrast to the superficial Sylvian vein that was dark in color (white arrows in Fig. 3B). Indocyanine green (ICG) video angiography revealed the apparent early inflow of arterial blood from the anastomosis site (dotted circle in Fig. 3C) toward the adjacent cortical veins (black arrowheads in Fig. 3D) and its downstream superficial Sylvian vein (white arrows in Fig. 3E).
Postoperative brain MRA and CBF findings. (A) N-isopropyl-p-[123I] iodoamphetamine-SPECT on POD 1 showed increased CBF in the right hemisphere compared with the preoperative status. (B) MRA on POD 2 demonstrated apparently patent STA-MCA anastomosis (dotted circle). (C) Higher magnification at the site of anastomosis is shown in Panel B. CBF: cerebral blood flow, MCA: middle cerebral artery, MRA: magnetic resonance angiography, POD: postoperative day, SPECT: single photon emission computed tomography, STA: superior temporal artery.
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F4
Postoperative 123I-IMP-SPECT on the postoperative day (POD) 1 and 7 demonstrated significant improvement of CBF without evidence of local CHP (Fig. 4A). Postoperative MRA on POD 2 revealed patency of the bypass (Fig. 4B and 4C).