Retrograde Flow Into the Internal Jugular Vein in a Hemodialysis Patient Mimicking Dural Arteriovenous Fistula: A Case Report.

Arterial spin labeling (ASL) and three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) are sensitive tools to detect dural arteriovenous fistula (DAVF), but hyperintensity in these images is also caused by jugular venous reflux. We present a case of a patient with renal failure on hemodialysis with retrograde flow into the internal jugular vein (IJV) mimicking DAVF. A 74-year-old man with a radial arteriovenous fistula for hemodialysis experienced transient dizziness. The TOF MRA and ASL revealed high signal intensity, suggesting the presence of a DAVF in the left transverse and sigmoid sinuses and the IJV. Digital subtraction angiography (DSA) revealed no evidence of a DAVF but showed retrograde flow into the IJV via his radial shunt. In hemodialysis patients, a high-flow shunt can cause fast retrograde flow into the dural sinuses and might lead to intracranial hypertension. The ASL images are useful for early detection and careful observation.

Case report: Unruptured small middle cerebral artery aneurysm with perianeurysmal edema.

Background: Perianeurysmal edema (PAE) has a tendency to occur in embolized aneurysms but also in partially thrombosed, large, or giant aneurysms. However, there are only a few cases recorded in which PAE was detected in untreated or small aneurysms. We suspected that PAE might be an impending sign of aneurysm rupture in these cases. Herein, we presented a unique case of PAE that was related to an unruptured small middle cerebral artery aneurysm. Case description: A 61-year-old woman was referred to our institute due to a newly formed abnormal fluid-attenuated inversion recovery (FLAIR) hyperintense lesion in the right medial temporal cortex. Upon admission, the patient did not present with any symptoms or complaints; however, FLAIR and CT angiography (CTA) suggested an increased risk of aneurysm rupture. Aneurysm clipping was conducted, and no evidence of subarachnoid hemorrhage and hemosiderin deposits around the aneurysm and brain parenchyma was noted. The patient was discharged home without any neurological symptoms. MRI taken at eight months post-clipping revealed complete regression of the FLAIR hyperintense lesion around the aneurysm. Conclusion: PAE in unruptured, small aneurysm is thought to be an impending sign of aneurysm rupture. Early surgical intervention is critical even for small aneurysms with PAE.

Endovascular Coil Embolization for Recurrent Bow Hunter's Stroke.

Bow hunter's stroke is a rare cause of vertebrobasilar infarction. There is no consensus regarding the optimal treatment. We herein report a case of bow hunter's stroke successfully treated by endovascular treatment. A 70-year-old man presented with central vertigo. Magnetic resonance imaging (MRI) showed posterior circulation infarcts. Dynamic angiography revealed thrombus formation and hypoperfusion of the right vertebral artery upon head rotation to the left. Endovascular parent artery occlusion of the right vertebral artery was performed, and there was no recurrence at follow-up MRI. Endovascular parent artery occlusion might be a useful treatment for bow hunter's stroke.

Unruptured cerebral aneurysms with the segmental duplicated middle cerebral artery formed a fenestrated structure at origin.

BACKGROUND: Middle cerebral artery (MCA) has a significantly lower incidence of anatomical variations than other intracranial arteries. We present an extremely rare case of unruptured aneurysms with the segmental duplicated MCA (d-MCA) formed a fenestrated structure at origin. CASE DESCRIPTION: A 55-year-old female underwent direct surgery for the unruptured aneurysms at the top of the right internal cerebral artery with d-MCA. The d-MCA branches separated at the right internal cerebral artery top and had comparable with that of the main MCA trunk. Moreover, there was an anastomosis between the d-MCA branches. We diagnosed this anastomosis as segmental d-MCA. Two aneurysmal domes were identified during surgery at the origin of the d-MCA, which the main dome protruding backward was wide necked and another small one was collapsed or thrombosed protruding forward. We used a fenestrated clip for the posterior projecting dome, and the aneurysms were successfully obliterated. CONCLUSION: Although cerebral aneurysms associated with d-MCA are rare, there are technical difficulties in the surgical management. A fenestrated clip might be most reasonable to obtain patency of the parent arteries for the posterior projecting aneurysms if the perforators can be avoided.

Subarachnoid hemorrhage due to a craniocervical junction arteriovenous fistula associated with thrombus formation in the internal jugular vein: illustrative case.

BACKGROUND: A craniocervical junction arteriovenous fistula (CCJAVF) is a rare vascular malformation, and its etiology remains unclear. Here, to the best of the authors' knowledge, they present the first case of CCJAVF associated with thrombus formation in the ipsilateral internal jugular vein. OBSERVATIONS: An 80-year-old man presented with a sudden occipital headache. Computed tomography revealed a subarachnoid hemorrhage surrounding the brainstem and upper cervical cord. Digital subtraction angiography showed a CCJAVF fed by the left C2 radiculomeningeal artery with ascending intracranial drainage and epidural plexus. After endovascular treatment, the authors retrospectively found that his ipsilateral internal jugular vein and innominate vein were occluded with a huge thrombus at admission. LESSONS: This case suggested a restricted antegrade venous flow due to thrombus-induced progressive retrograde intracranial drainage causing hemorrhage. Venous hypertension should be considered one of the causes of hemorrhage due to CCJAVF as well as intracranial arteriovenous fistulas.

Successful Endovascular Treatment for Middle Cerebral Artery Occlusion Caused by the Thrombus Formation in the Pulmonary Vein Stump Following Left Upper Lung Lobectomy.

Thrombus formation in the pulmonary vein (PV) stump after lung resection can cause rare cases of cerebral infarction. These infarctions can result in embolism and ischemia in the relatively large intracranial vessels, severely impacting the quality of life (QOL) of these patients. We performed endovascular thrombectomy successfully for this rare complication after lung lobectomy. A 73-year-old woman with paroxysmal atrial fibrillation (AF) suffered from sudden left complete hemiplegia 19 days after undergoing a left upper lung lobectomy (LUL). Magnetic resonance imaging (MRI) showed middle cerebral artery occlusion. Her left hemiplegia improved after the endovascular thrombectomy. Cardiogenic embolism was first suspected, but contrast-enhanced computed tomography (CECT) showed thrombus formation in the PV stump. We continued anticoagulant therapy, and the thrombus resolved completely two months after the stroke. Our patient had a relatively good outcome due to the immediate reperfusion of the affected area. This embolic source may be overlooked because AF frequently occurs after thoracic surgeries. Care should be taken during the postoperative phase to avoid overlooking these emboli. All thoracic surgeons should be informed about mechanical thrombectomy as an effective treatment for postoperative cerebral infarction.

Unusual course of the vagus nerve passing anterior to the internal carotid artery during carotid endarterectomy.

BACKGROUND: Carotid endarterectomy (CEA) is a conventional surgical technique to prevent ischemic stroke and the effectiveness for advanced lesions is established in many large studies. The vagus nerve is one of the cranial nerves that we usually encounter during CEA manipulation, which is identified as located posterior to the vessels in a position posterolateral to the carotid artery and posteromedial to the internal jugular vein. CASE DESCRIPTION: We experienced an extremely rare case of the vagus nerve passing anterior to the internal carotid artery during CEA. CONCLUSION: We should be careful not to accidentally cut off because the variation of the vagus nerve can be mistaken for an ansa cervicalis. A delicate and complete dissection to understand the variation of the vagus nerve is crucial to minimize the risk of cranial nerve injury during CEA.

[Asymptomatic Aplastic or Twig-Like Middle Cerebral Artery Associated with Unruptured Cerebral Aneurysms at the Origin (A1) of a Collateral Artery and the Anterior Communicating Artery: A Case Report with Multiple Intracranial Atherosclerotic Stenoses].

We report a rare case of asymptomatic aplastic or twig-like middle cerebral artery (Ap/T-MCA) with small unruptured aneurysms at the origin (A1) of the anomalous collateral artery containing plexiform (twig-like) networks and in the anterior communicating artery. In Ap/T-MCA, other cerebrovascular systems are usually considered to exhibit normal findings not associated with atherosclerosis. At first admission, atherosclerotic M1 occlusion was suspected because of the patient's risk factors and multiple stenoses in major intracranial arteries. Cerebral blood flow (CBF) studies revealed reduction of resting CBF and vascular reserve in the ipsilateral MCA territory. After 5 years, a diagnosis of Ap/T-MCA was reached based on detailed image examination and intraoperative findings during aneurysm clipping in combination with extracranial-intracranial (EC-IC) bypass. It should be noted that atherosclerosis can coexist with Ap/T-MCA, which is considered a congenital anomaly in which bleeding often occurs due to a ruptured aneurysm within the fragile collateral vessels. In previous reports, A1 aneurysms at the origins of the collateral arteries ruptured even when they were small. Aggressive radical surgery using EC-IC bypass can be considered for the treatment of unruptured aneurysms associated with Ap/T-MCA, but further research is needed. (Received September 14, 2020; Accepted November 4, 2020; Published 1 April, 2021).

A1 Segment Unruptured Aneurysm of Persistent Primitive Olfactory Artery Coexisted with Accessory Middle Cerebral Artery.

A persistent primitive olfactory artery (PPOA) is a rare anomaly of anterior cerebral artery (ACA), which generally arises from the internal carotid artery (ICA), runs along the olfactory tract, and makes a hairpin bend to supply the territory of the distal ACA. PPOA is also associated with cerebral aneurysms. An accessory MCA is a variant of the middle cerebral artery (MCA) that arises from either the proximal or distal portion of the A1 segment of the ACA, which runs parallel to the course of the MCA and supplies some of the MCA territory. We experienced a rare case of coexistence of PPOA with an unruptured aneurysm and accessory MCA. Three-dimensional computed tomographic angiography (3D-CTA) has an excellent picture of the spatial relationship of the surrounding bony and vascular structure.

Carotid Endarterectomy Using Lone Star Retractor System.

Cervical carotid disease is typical atherosclerosis, which is responsible for ischemic stroke. The effectiveness of carotid endarterectomy (CEA) for advanced carotid stenosis has been established in many large studies, and CEA is the gold standard in surgical treatment. On the other hand, endovascular carotid artery stenting (CAS) has become increasingly popular recently. It is very important to avoid any complications to maintain the effectiveness of CEA. The retractor device is important for the exposure of carotid arteries and for the safe surgical manipulation. We have started to use lone star retractor system (LSRS) to deploy the surgical field. LSRS provides the usability to handle and a shallower surgical field without the disturbance of surgical manipulation. And it can facilitate exposure of the distal internal carotid artery because surgeon can retract freely in whole circumference by towing with moderate strength. LSRS may bring the smoother and easier surgical manipulations in CEA.

Current status of a helicopter transportation system on remote islands for patients undergoing mechanical thrombectomy.

BACKGROUND: Mechanical thrombectomy (MT) is standard treatment for acute ischemic stroke (AIS) with large-vessel occlusion within 6 h of symptom onset to treatment initiation (OTP). Recent trials have extended the therapeutic time window for MT to within 24 h. However, MT treatment remains low in remote areas. Nagasaki Prefecture, Japan has many inhabited islands with no neurointerventionalists. Our hospital on the mainland is a regional hub for eight island hospitals. We evaluated clinical outcomes of MT for patients with AIS on these islands versus on the mainland. METHODS: During 2014-2019, we reviewed consecutive patients with AIS who received MT at our hospital. Patients comprised the Islands group and Mainland group. Patient characteristics and clinical outcomes were compared between groups. RESULTS: We included 91 patients (Islands group: 15 patients, Mainland group: 76 patients). Seven patients (46.7%) in the Islands group versus 43 (56.6%) in the Mainland group achieved favorable outcomes. Successful recanalization was obtained in 11 patients (73.3%) on the islands and 67 (88.2%) on the mainland. The median OTP time in the Islands was 365 min. In both the Islands and Mainland groups, the OTP time and successful recanalization were associated with functional outcome. The modified Rankin Scale (mRS) score at 90 days ≤2 was obtained in two patients and mRS = 3 in four patients among eight patients with OTP time >6 h. CONCLUSIONS: Few patients with AIS on remote islands have received MT. Although patients who underwent MT on the islands had longer OTP, the clinical outcomes were acceptable. OTP time on remote islands must be shortened, as this is related to functional outcome. In some cases with successful recanalization, a favorable outcome can still be obtained even after 6 h. Even if OTP exceeds 6 h, it is desirable to appropriately select patients and actively perform MT.

[Orbital Compartment Syndrome Perhaps Secondary to Intra-Orbital Fluid Retention and Orbital/Palpebral Emphysema Following Frontotemporal Craniotomy for an Unruptured Cerebral Aneurysm:A Case Report].

A 58-year-old woman underwent left frontotemporal craniotomy for clipping of an unruptured cerebral aneurysm. A small defect was accidentally created in the orbital roof intraoperatively. The patient developed left eyelid edema and ocular pain after recovery from anesthesia. The following day, the eyelid edema worsened, and she had difficulty opening her eyes. On the 9th postoperative day, she noticed diminished visual acuity and diplopia in her left eye when she was able to spontaneously open her eyes. Ophthalmological evaluation revealed mild left visual loss, decreased light reflex, ophthalmoplegia, ptosis, and chemosis. Computed tomography(CT)/magnetic resonance imaging revealed left proptosis, optic nerve stretching, intra-orbital fluid retention, and orbital/palpebral emphysema. She was diagnosed with orbital compartment syndrome(OCS)and received conservative treatment;however, her visual acuity did not improve. OCS observed after cerebral aneurysm surgery is rare;to date, only 24 cases have been reported in the available literature. Although the mechanism of OCS after craniotomy is unclear, it may be attributed to ocular compression by a muscle flap or increased intra-orbital pressure secondary to venous congestion. In the present case, the left superior ophthalmic vein and cavernous sinus were not clearly visualized on CT angiography. Therefore, we concluded that the right superior ophthalmic vein and superficial facial veins underwent dilatation and served as collateral circulation of the left orbital venous system. We speculate that OCS occurred secondary to increased intra-orbital pressure, possibly caused by inflow of cerebrospinal fluid with air into the orbit through a small bone defect that was accidentally created during craniotomy in a setting of orbital venous congestion.

[Early Development of a Symptomatic Expanding Porencephalic Cyst in the Hematoma Cavity after Subcortical Hematoma Removal in an Adult:A Case Report].

A 69-year-old woman presented on an emergency basis, with headache and left hemiparesis. Initial head CT at the time of admission revealed a large subcortical hematoma with perihematomal edema extending from the right parietal to the occipital lobe. A small part of the hematoma extended toward the trigone of the right lateral ventricle. CT angiography revealed no vascular abnormalities. Emergency craniotomy was erformed, and the patient's initial postoperative course was unremarkable. However, the patient's neurological symptoms worsened 10 days postoperatively, and CT revealed a new low-density cystic lesion with perifocal edema at the site of hematoma removal, in addition to severe cerebral compression. We performed a reoperation, and intraoperatively we observed hematoma fluid mixed with cerebrospinal fluid without any abnormal blood vessels or neoplastic lesions in the hematoma cavity. We identified the choroid plexus deep within the surgical field, and slight leakage of cerebrospinal fluid was detected from the ventricular aspect, indicating the formation of a small passage between the hematoma cavity and the ventricle. After the second operation, her postoperative course was uneventful without recurrent cyst formation. An early symptomatic expanding porencephalic cyst in the hematoma cavity after removal of an intracerebral hematoma is rare, and only a few cases have been reported in the literature. Based on literature review and considering the likely mechanism of cyst development, we speculated that progressive cyst expansion could be attributed to a check valve mechanism between the ventricle and the cavity from which the hematoma was removed, as observed in the present case.

First Bite Syndrome Following Carotid Endarterectomy.

A 67-year-old man with a high position carotid plaque presented with severe pain in ipsilateral parotid region several days after carotid endarterectomy (CEA). The pain occurred at the first bite of each meal and resolved as further bite. We diagnosed the pain as first bite syndrome (FBS). FBS is infrequent but known as a complication associated with parapharyngeal space surgery. The pain is characterized by sharp pain in the parotid region associated with mastication. The cause is unclear but thought to the result from sympathetic denervation of the parotid gland, followed by parasympathetic nerve hypersensitivity. Only five cases associated with carotid endarterectomy (CEA) have been reported. We should be in mind that CEA for high position plaque is one of the risk factors to cause FBS associated with CEA. Neurologists and vascular surgeons as well as otolaryngologists should all be informed FBS as one of the complications after carotid endarterectomy.

[Endovascular Treatment of a Ruptured Aneurysm of the Right Vertebral Artery with an Aberrant Right Subclavian Artery].

We report a rare case of the endovascular treatment of a ruptured aneurysm of the right vertebral artery with an aberrant right subclavian artery(ARSA). A 60-year-old woman was urgently admitted because of consciousness disturbance. Brain CT showed subarachnoid hemorrhage, and CT angiography showed a right vertebral ruptured aneurysm. Endovascular treatment of the aneurysm was performed via a transfemoral approach. During the endovascular treatment, the right subclavian artery was found to diverge from the descending aorta on the periphery of the left subclavian artery. An ARSA was detected, and the right vertebral artery(VA)originated from the ARSA. The guiding catheter was passed through the right VA via an ARSA, and the aneurysm was completely embolized. The patient was transferred to another hospital on day 44 without any motor weakness. To our knowledge, this is the first case of an ARSA with a ruptured aneurysm in the right VA for which endovascular treatment was successfully performed via the ARSA. In patients with an ARSA or aberrant left subclavian artery, the artery could merge with Kommerell's diverticulum(KD)at its origin and be histologically fragile. Thus, in patients with an ARSA, attention should be paid to catheterization to avoid injuring the KD. CT angiography of the aortic arch might be considered before endovascular treatment.

[Reversible Cerebral Vasoconstriction Syndrome with Cortical Subarachnoid Hemorrhage due to Acute Cortical Infarction Beneath the Sulcus:A Case Report].

We report a rare case of reversible cerebral vasoconstriction syndrome(RCVS)with cortical subarachnoid hemorrhage(cSAH)associated with a fresh cortical infarction beneath the sulcus with thick cSAH. A 34-year-old woman presented with history of thunderclap headache. She was transferred to our hospital for further examination of a cSAH in the left frontal lobe. Results of the cerebrospinal fluid examination were unremarkable, but three-dimensional rotational angiography revealed multiple instances of narrowing of the cortical branches of the anterior and middle cerebral arteries, suggesting the diagnosis of RCVS. Diffusion weighted imaging(DWI)demonstrated a small cortical area with high-signal intensity around the sulcus , where a thick cSAH clot was observed. This cortical lesion appeared as low-signal intensity on the apparent diffusion coefficient maps, and the follow-up T2-weighted images(obtained 3 months after onset)demonstrated a residual lesion that was smaller than the initial DWI abnormality with high-signal intensity;thus indicating the presence of a coincident fresh cortical infarction. The position of the infarct next to the thickest portion of cSAH suggested that it was the bleeding source of the cSAH. Ten days after onset, the cerebral blood flow and volume in the cortex around the cSAH increased as compared to the same area on the contralateral side. These findings suggested that at least one of the bleeding mechanisms of the cSAH was related to the hemorrhagic infarction or subpial hemorrhage resulting from the "ischemia-reperfusion injury" due to the acute disturbance of the pial vessel microcirculation with subsequent rapid resolution of the blood flow during the early phases of RCVS. These dynamics could not be demonstrated with contemporary angiographic imaging.

[A Rare Case of an Unruptured Fusiform Aneurysm Arising from the Lateral Limb of the Fenestration of the Anterior Medullary Segment of the Posterior Inferior Cerebellar Artery].

We report an extremely rare case of fenestration of the posterior inferior cerebellar artery(PICA)with an aneurysm at the fenestrated portion. A 60-year-old man with a medical history of hemophilia was referred to our hospital for further examination of unruptured aneurysms at the left PICA and vertebral artery(VA)that were incidentally discovered by computed tomography angiography 5 years ago during an examination of spontaneous intracerebral hemorrhage. A 3D-rotational angiography revealed a fenestration(4.7×1.4mm)in the anterior medullary segment of the left PICA associated with an unruptured fusiform aneurysm(7.2×6.1mm)arising from the entire lateral limb of the fenestrated segment. The left VA aneurysm had a wide neck(7.2×6.8mm)and was located at the portion just distal to the bifurcation of the left PICA. The patient requested conservative management of both aneurysms because no significant change in the size or shape of either had been observed during the last 5 years. An extensive review of the literature revealed that nine cases of PICA fenestration have been reported. Among these, detailed medical records were described in seven cases, and an aneurysm at the fenestrated artery had been detected in only 2 cases. To our knowledge, this is the first report of a PICA fenestration associated with an unruptured aneurysm at the fenestrated segment. Embryologically, the PICA fenestration may represent a remnant of plexiform arterial channels between the primitive VA and primitive lateral vertebrobasilar anastomosis.

[A Case of Dural Arteriovenous Fistula Involving the Superior Sagittal Sinus that Presented as a Primary Intraventricular Hemorrhage].

We report an extremely rare case of dural arteriovenous fistula(DAVF)involving the superior sagittal sinus(SSS)that presented as a primary intraventricular hemorrhage(PIVH). A 79-year-old man who presented with disturbance of consciousness and vomiting was transferred to our hospital. The initial head CT revealed an intraventricular hemorrhage in the lateral, third, and fourth ventricles, predominantly involving the right lateral ventricle associated with obstructive hydrocephalus. CT angiography and three-dimensional rotational angiography(3D-RA)revealed SSS-DAVF with retrograde venous drainage from the cortical venous system to the subependymal venous system through engorged superficial/anastomotic/deep medullary or transcerebral veins, showing a pseudophlebitic pattern. A severe stenosis of the SSS was observed at the site just proximal to the shunting point. A varix of the right transvers caudate vein(TCV)was observed within the thickest portion of the hematoma in close contact with the wall of the right lateral ventricle. A stenosis of the branching point of the right TCV was detected on the 3D-RA image. The DAVF was completely cured after transarterial embolization. The varix gradually shrank and finally disappeared after 2 months. This is the first report of a case of PIVH due to SSS-DAVF with a subependymal varix considered as the bleeding point. Serial gadolinium-enhanced MR images clearly showed the shrinking of the varix. Our case is the second reported case of spontaneous resolution of the varix after embolization of the DAVF. The obstructive changes of the two venous outflow pathways(SSS/TCV)might further worsen the state of venous congestion in the deep medullary venous system and eventually lead to formation and rupture of the varix.