PMC8769474_01
Case 1, A 52-year-old man undergoing treatment for hypertension. (A) Cerebellar hemorrhage (white arrow) is observed on head CT performed for a headache. (B) Cerebral angiography (lateral view) of the left ICA shows a dural AVF with the tentorial artery (blue arrowhead) as the main feeder and a single drainer that drains into the straight sinus through the superior vermian vein. (C) Cerebral angiography (lateral view) of the left external carotid artery shows that the MMA (blue arrow) and OA (blue arrowhead) are also dural AVF feeders. (D) Cerebral angiography (lateral view) of the left VA shows the development of the left SCA and the left PICA (red arrows). A basilar artery-SCA artery aneurysm (black arrow) and a PICA distal aneurysm (black arrowhead) are observed, which are thought to be flow-related aneurysms. (E and F) Fusion images of the left ICA angiography (white) and left VA angiography (red) created using syngo X Workplace (SIEMENS). (E) shows the long-axis view of the drainer and (F) the short-axis view of the drainer at the dotted line position. In each image, the tentorial artery (white arrow) forms a shunt on the dura and continues to the drainer (white arrowhead). Pial arteries of the PICA and SCA form a nidus in the brain (red arrow) and continue to a different drainer (red arrowhead) from the dural AVF drainer. The two drainers join at the subarachnoid space near the tentorial sinus (asterisk). Thus, this condition is diagnosed as the coexistence of a pial AVM. (G) Surgical findings confirm the junction (asterisk) of the dural AVF drainer (white arrowhead) and the pial AVM drainer (red arrowhead). (H) Because clipping the dural AVF drainer alone does not normalize the red vein, the coexistence of a pial AVM is confirmed. (I) A pial AVM could be visualized after severing the dural AVF drainer. Severed site of the dural AVF drainer (black arrowhead). (J) After pial AVM extraction, the red vein disappears. (K) Pathological findings of the extracted intracerebral lesion (Elastica van Gieson stain, 100x magnification) show aggregation of abnormal dilated blood vessels with thin walls and intervening brain parenchymal tissue, and an AVM is diagnosed. AVF: arteriovenous fistula, AVM: arteriovenous malformation, CT: computed tomography, ICA: internal carotid artery, MMA: middle meningeal artery, OA: occipital artery, PICA: posterior inferior cerebellar artery, SCA: superior cerebellar artery, VA: vertebral artery.
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Case 1 (Fig. 2): A 52-year-old man with a history of hypertension visited a local physician because of headache. Head computed tomography (CT) and magnetic resonance imaging (MRI) showed a left cerebellar hemorrhage from the left tentorial dural AVF (Fig. 2A), and the patient was referred to our institution for treatment. AVF supplied mainly by the tentorial artery, middle meningeal artery (MMA), and occipital artery (OA) were observed on cerebral angiography (Figs. 2B and 2C). A single drainer of the dural AVF drained into the straight sinus through the superior vermian vein. Since they appeared to aggregate in the brain, the coexistence of a pial AVM were suspected (Fig. 2D). The fusion images showed that the pial artery from the PICA and SCA gathered in the brain, formed a nidus, and became a separate drainer from the dural AVF drainer, eventually joining the dural AVF drainer (Figs. 2E and 2F). As expected preoperatively, the dural AVF drainer and pial AVM drainer joined in the subarachnoid space (Fig. 2G). The dural AVF drainer was cauterized and cut first, and this expanded the operative field such that the pial AVM could be visualized (Fig. 2I). The pathological findings of the extracted intracerebral lesion were characteristic of a typical pial AVM (Fig. 2K).
PMC8769474_02
Case 2, A 75-year-old man with a dural AVF that is found coincidentally. Anteroposterior view (A) and lateral view (B) of the right CCA angiography show a tentorial dural AVF with the MMA and OA as the feeders. The pial artery supply of the MMA (white arrow) is also feeding the dural AVF. Anteroposterior view (C) and lateral view (D) of the right VA angiography show aggregation of the pial artery of the PCA (red arrow). (E) MRA (coronal image) shows the presence of blood vessel aggregation on the dura (white arrow) and in the brain (red arrow). (F) The drainer is clipped with a titanium clip, and the surgery is then finished after confirming the disappearance of the shunt with indocyanine green videoangiography. (G) CT on the day after surgery shows intracerebral hemorrhage with an acute subdural hematoma. (H) Coronal fusion images of the right CCA angiography (white) and right VA angiography (red) created with syngo X Workplace (SIEMENS); preoperative images are re-examined. The meningeal artery and the pial artery of the MCA form the dural AVF (white arrow). The pial artery of the PCA aggregates in the brain and forms a nidus as the pial AVM (red arrow) and both drainers join immediately above the transverse sinus (asterisk). (I) Reviewing the intraoperative image, the junction (asterisk) of the dural AVF drainer (white arrowhead) and the pial AVM drainer (red arrowhead) appears to be present. AVF: arteriovenous fistula, AVM: arteriovenous malformation, CCA: common carotid artery, CT: computed tomography, MCA: middle cerebral artery, MMA: middle meningeal artery, MRA: magnetic resonance angiography, OA: occipital artery, PCA: posterior cerebral artery, VA: vertebral artery.
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Case 2 (Fig. 3): A 75-year-old man underwent head and neck MRI due to neck pain, and a right tentorial dural AVF was found coincidentally. Cerebral angiography showed that the MMA, OA, and tentorial artery were supplying the dural AVF, and that pial arteries from the middle cerebral artery (MCA), posterior cerebral artery (PCA), and SCA were also involved as feeders of the shunt (Figs. 3A-3D). Magnetic resonance angiography (MRA) showed intracerebral gathering of the pial artery from the PCA (Fig. 3E); however, the coexistence of a pial AVM was not noticed at this point, and surgery proceeded. After finishing the surgery with drainer clipping alone (Fig. 3F), an intracerebral hematoma with acute subdural hematoma was observed on head CT the following day (Fig. 3G). The same software as in Case 1 was used to create fusion images of the right common carotid artery angiography and right VA angiography images (Fig. 3H). MCA and SCA joined the shunt point of the dural AVF, but the pial artery from the PCA formed a nidus in the brain parenchyma. Moreover, reviewing the intraoperative image, the junction of the dural AVF drainer, and the pial AVM drainer appeared to be present (Fig. 3I).