PMC8769412_01
(a) MRA shows an aneurysm of the MCA at the left bifurcation (long arrow) and the anomalous azygos ACA (arrow). (b) Lateral view of MRA shows no definitive aneurysm at the azygos ACA bifurcation (arrow). (c) Oblique view of MRA shows overlapping vessels, with small vascular bulging at the azygos ACA bifurcation (arrow) and a part of the aneurysm at the MCA bifurcation. (long arrow). ACA: anterior cerebral artery, MCA: middle cerebral artery, MRA: magnetic resonance angiography.
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F1
Magnetic resonance angiography (MRA) showed a saccular aneurysm, 5 mm in diameter, arising at the bifurcation of the left middle cerebral artery (MCA; M1) and an azygos ACA without an aneurysm, with no other anomalies on magnetic resonance imaging (MRI) (Fig. 1).
Eight years later, follow-up MRA shows a large new aneurysm of the azygos ACA. ACA: anterior cerebral artery, MRA: magnetic resonance angiography.
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F2
MRI. MRA showed a relatively large aneurysm (about 9 mm in diameter) arising from the bifurcation of the azygos ACA as a de novo aneurysm (Fig. 2).
(a) The interhemispheric operative field is very narrow. First, the right blade of the clip is inserted between the anterior aneurysmal neck and the origin of the pericallosal artery on the right. The left one is put between the aneurysmal neck and the left pericallosal artery. (b) Operative view shows bilateral pericallosal arteries, the posterior aneurysm, and the anterior aneurysm closed by the first clip. (c) Operative view shows the second clip in L formation applied to the posteriorly residual aneurysm. Thus, multiple clips are required to close the aneurysm. The schema presents the final clips applied to the azygos ACA. ACA: anterior cerebral artery.
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F3
Five days later, the aneurysm was identified and clipped with complete occlusion by multiple clips through an interhemispheric approach (Fig. 3).
Indocyanine green (ICG) image demonstrates the disappearance of the aneurysm using multiple clips.
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F4
Complete occlusion of the azygos ACA aneurysm was confirmed by indocyanine green during microscopic surgery (Fig. 4).