PMC9610041_01
Imaging findings before and during thrombus retrieval. (a) Magnetic resonance imaging diffusion-weighted imaging showing a high signal intensity area in the left middle cerebral artery territory (diffusion-weighted imaging - Alberta Stroke Program Early Computed Tomography Score 4), with a small high signal intensity area in the peripheral region of the left anterior cerebral artery. (b and c) Early-phase left internal carotid artery angiography before thrombectomy (b: anteroposterior view and c: lateral view) showing occlusion of the distal left middle cerebral artery (arrowhead). (d) Late-phase left internal carotid artery angiography before thrombectomy (lateral view) showing occlusion of the left peripheral pericallosal artery (arrow). (e and f) Early-phase left internal carotid artery angiography (e: anteroposterior view and f: lateral view) after thrombectomy showing recanalization of the M1 segment (arrowhead). (g) Late-phase left internal carotid artery angiography after thrombectomy showing occlusion of the left peripheral pericallosal artery (arrow).
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Alberta Stroke Program Early CT Score 4), with a small high signal intensity area in the peripheral region of the left ACA [Figure 1a], which was barely delineated in fluid-attenuated inversion recovery sequence. The left internal carotid artery angiography showed occlusion of the distal part of the M1 segment of the left MCA and the peripheral region of the pericallosal artery of the left ACA [Figures 1b-d]. On the second attempt, the clot was retrieved, and reperfusion of the left MCA was achieved with a puncture-to-reperfusion time of 51 min [Figure 1e]. Because the occlusion site of the left pericallosal artery was peripheral and collateral blood flow was observed distal to the occlusion site, thrombectomy was not performed [Figures 1f and g]. The location of the aneurysm coincided with the occlusion area identified during thrombectomy [Figures 1d and g].
Imaging findings after thrombus retrieval. (a) Head magnetic resonance imaging obtained 4 h after thrombectomy showing a reduced diffusion-weighted imaging high signal intensity area in the left middle cerebral artery territory with a small high signal intensity area in the peripheral region of the left anterior cerebral artery. (b) Head computed tomography obtained 24 h after thrombectomy showing a small high-density area around the infarct area in the anterior cerebral artery territory. (c) Head computed tomography obtained 38 h after thrombectomy showing subcortical hemorrhage in the left anterior cerebral artery territory and intraventricular hemorrhage. (d) Head computed tomography obtained 48 h after thrombectomy showing enlargement of subcortical hematoma and intraventricular distension. (e) Postoperative computed tomography showing residual hematoma around the infarct area in the left anterior cerebral artery.
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Head magnetic resonance imaging obtained 4 h after thrombectomy showed a reduced diffusion-weighted imaging high signal intensity area in the left MCA territory with a small high signal intensity area in the peripheral region of the left ACA [Figure 2a]. Head CT obtained 24 h after thrombectomy showed a small high-density area in the left ACA territory [Figure 2b]. Head CT showed subcortical hemorrhage in the left ACA territory and intraventricular hemorrhage [Figure 2c]. Head CT obtained 48 h after thrombectomy showed enlargement of subcortical hematoma and intraventricular distension [Figure 2d]. Postoperative CT showed residual hematoma around the infarct area in the left ACA territory [Figure 2e].
Imaging findings of the thrombus. (A-C) Overall thrombus findings. The arrows show the proximal side of the M1 segment of the middle cerebral artery. (a) The thrombus was a single mass of 8 x 5 mm, with a visually recognizable red component mixed with a localized white component (arrowheads). It was firm and maintained the shape of the vessel at the distal part of the M1 segment and the bifurcation. (b) Hematoxylin-eosin staining showing that the thrombus consisted mainly of fibrin and platelets. (c) Consistent with the visually recognizable white component of the thrombus, Gram-positive cocci were observed. (D and E) D and E correspond to the squares "a" and square "b" in B, respectively. Hematoxylin-eosin staining showing the formation of spherical bacterial colonies at the margins of the thrombus and focally abundant neutrophils. (F and G) F and G correspond to the squares "a" and square "b" in C. The spherical bacteria at the margins of the thrombus were Gram staining positive.
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It was firm and maintained the shape of the vessel at the distal part of the M1 segment and the bifurcation [Figure 3A]. Gram staining showed that the bacteria were Gram-positive cocci [Figures 3B-G]. Consistent with the visually recognizable white component of the thrombus, Gram-positive cocci were observed [Figures 3A-C].
Imaging findings of the aneurysm before and during embolization. (a) An axial view of computed tomography angiography of the head showing an aneurysm in the peripheral left anterior cerebral artery (arrow). (b-d) The left internal carotid artery angiography (b: anteroposterior view, c: three-dimensional anteroposterior view, and d: lateral view) showing a 5.8 mm saccular aneurysm in the peripheral region of the pericallosal artery of the anterior cerebral artery (arrows) and no aneurysm formation in the recanalized distal part of the left M1 segment (arrowheads). (e and f) The left internal carotid artery angiography after embolization (e: anteroposterior view and f: lateral view) showing occlusion of the aneurysm.
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CT angiography was performed, which revealed an aneurysm in the peripheral region of the left ACA [Figure 4a]. The left internal carotid artery angiography and three-dimensional rotational angiography showed a 5.8 mm saccular aneurysm in the peripheral region of the pericallosal artery of the left ACA [Figures 4b-d]. Posttreatment angiography showed complete occlusion of the aneurysm [Figures 4e and f].