PMC4392556_01
(a) Diffusion-weighted MR image at onset indicating acute watershed infarction due to hemodynamic insufficiency. (b and c) MR angiogram (b) and lateral DSA of the left common carotid artery (c) at the onset showing occlusion of the left ICA at the cervical portion (arrow). (d) Lateral DSA of the left common carotid artery after the first anastomosis in which the blood flow from the STA perfuses both proximal and distal to the anastomotic site (arrow). (e and f) MR angiogram (e) and lateral DSA of the left common carotid artery (f) performed 2.5 years after the first anastomosis showing de novo aneurysm at the anastomotic site (arrow)
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F1
Magnetic resonance (MR) imaging revealed acute cerebral infarction in the left watershed area [Figure 1a], and MR angiography and digital subtraction angiography (DSA) demonstrated occlusion of the left ICA at the cervical portion [Figure 1b and c]. Postoperative DSA showed good patency of the anastomosis [Figure 1d], and 99mTc-ECD SPECT demonstrated improvement of cerebral blood flow. First follow-up MR angiography with an interval of 2 years (due to transient lost follow-up) showed de novo aneurysm [Figure 1e]. DSA performed 2.5 years after anastomosis (at the age of 66) revealed a 19.0-mm de novo saccular aneurysm at the anastomotic site [Figure 1f].
(a) Intraoperative photograph of the first STA-MCA anastomosis (arrowhead). (b and c) Intraoperative photographs of the trapping of the aneurysm and second ECA-RA-M2 and STA-M4 anastomoses showing the de novo aneurysm (arrow) pretrapping view (b), and posttrapping and anastomoses (arrowhead) view (c). d: M4 portion of the MCA distal to the anastomosis; M2: M2 portion of the MCA; p: M4 portion of the MCA proximal to the anastomosis; RA: Radial artery; STA: Superficial temporal artery
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F2
The patient underwent a left superficial temporal artery (STA)-middle cerebral artery (MCA) single anastomosis at the M4 portion with 15 sutures of 10-0 monofilament nylon [Figure 2a]. Clipping of the aneurysm was difficult, because the aneurysm was located exactly at the site of anastomosis [Figure 2b]. Finally, we performed anastomosis of the stumps of the STA and the distal M4 [Figure 2c].
Photomicrographs of resected de novo aneurysm. Left: Wall of the aneurysm dome (arrow) is thinned and consisted of collagen fibers. Asterisk = aneurysm lumen. Elastica van Gieson stain, original magnification x20. Right: Fragmented smooth muscle cells (arrowhead) are detected throughout the circumference. Alpha-smooth muscle actin stain, original magnification x20
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F3
Histological examination revealed that the aneurysm wall was thinned and consisted of collagen fibers, almost without media and internal elastic lamina, but immunohistochemistry revealed fragmented smooth muscle cells throughout the circumference, which established the diagnosis as true aneurysm [Figure 3].
(a and b) Postoperative lateral DSA of the left common carotid artery (a) and follow-up MR angiogram (b) showing good patency of the ECA-RA-MCA (arrow) and STA-MCA (arrowhead) anastomoses. C-E: T2-weighted MR image (c) and MR angiograms (d and e) performed 6 years after the second anastomosis showing second de novo aneurysm located remote from the anastomotic site (arrow: Aneurysm, arrowhead: Anastomotic site) (f)Lateral DSA of the left common carotid artery exhibiting the dilated artery (M3 portion) without visualization of the aneurysm lumen (arrow)
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F4
Postoperative DSA showed good patency of the anastomoses [Figure 4a], and he was discharged without neurological deficit. Follow-up MR angiography showed good patency of the anastomoses and no other abnormal findings over the next 3 years [Figure 4b]. Follow-up MR angiography for 3 years showed that the dilatation enlarged gradually and became a 12.0-mm saccular aneurysm at the nonbranching site [Figure 4c-e]. DSA. DSA revealed a slightly dilated vessel, but the aneurysm lumen was not detected [Figure 4f].
Sequencing chromatogram of the patient showing the heterozygote of the RNF213 c.14576G>A variant
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F5
Genetic analysis revealed the patient had RNF213 c.14576G>A variant (heterozygote) [Figure 5].