Ruptured aneurysm in collateral arteries with blood-flow impairment of posterior inferior cerebellar artery: a report of three cases.

Herein, we report three cases of cerebellar hemorrhage due to a ruptured small aneurysm located on a collateral artery compensating for one or more stenotic or occluded major cerebellar arteries. In each case, endovascular distant parent artery occlusion of both the collateral artery and aneurysm was performed to prevent rebleeding. A ruptured small aneurysm in a collateral artery may be observed in patients with hemorrhage in an atypical cerebellar region, especially in cases of stenosis or occlusion of the vertebral artery or posterior inferior cerebellar artery. Thus, cerebral angiography is recommended to rule out collateral artery aneurysm.

Frequency and Characteristics of Paraclinoid Aneurysm in Ruptured Cerebral Aneurysms.

OBJECTIVE: This study aimed to determine the frequency of paraclinoid aneurysms among ruptured cerebral aneurysms and compare paraclinoid aneurysms with other aneurysms to clarify the characteristics of ruptured paraclinoid aneurysms. METHODS: This study included 970 ruptured cerebral aneurysms treated at our hospital between 2003 and 2020. RESULTS: There were 15 cases (1.3%) of paraclinoid aneurysms with maximum diameters of 5-22 mm (mean±standard deviation [SD], 11.6±5.4 mm). Treatment consisted of clipping in four patients and endovascular treatment in 11. Factors significantly different in multivariate analysis for paraclinoid aneurysms compared with those for other aneurysms were a history of hypertension (odds ratio [OR], 1.2-9.8; p=0.021) and aneurysm ≥10 mm (OR, 7.5-390.3; p<0.001). The sites of paraclinoid aneurysm were ophthalmic artery type in nine patients, anterior wall type in five, medial wall type in one, and ventral wall type in zero. The medial wall type (22 mm) was significantly larger than the ophthalmic artery type (mean±SD, 7.2±2.0 mm) (p=0.003), and the anterior wall type (mean±SD, 12.2±4.8 mm) was significantly larger than the ophthalmic artery type (p=0.024). CONCLUSION: This study showed a low frequency of paraclinoid aneurysms among ruptured cerebral aneurysms. Most were upward-facing with relatively large aneurysms, and no aneurysms were smaller than 5 mm. With recent advances in endovascular treatment devices, paraclinoid aneurysms are easily treatable. However, the treatment indication of each paraclinoid aneurysm should be carefully considered.

A Case of Iatrogenic Dural Artery-Pial Vein Shunt Treated with Endovascular Treatment.

Objective: A few cases of postsurgical iatrogenic arteriovenous shunts have been reported, with the arterial blood flow directly entering the pial veins. Herein, we reported a patient with a dural artery-pial vein shunt found 1 year after aneurysmal clipping. Case Presentation: A 64-year-old male presented with generalized convulsion 1 year after cerebral aneurysmal clipping. A CT showed intracerebral hemorrhage in the temporo-occipital cortex and a dural artery-pial vein shunt in proximity to the previous craniotomy center. The arterial blood flow from the deep temporal artery, the middle meningeal artery, and the anterior auricular branch of the superficial temporal artery shunted into the superficial middle cerebral vein, with evident cortical venous reflux. Embolization was performed with n-butyl-2-cyanoacrylate and completely occluded the shunt. The patient was discharged without neurological deficits. Conclusion: Endovascular liquid embolization may be an effective treatment for iatrogenic dural artery-pial vein shunt.

Magnetic Resonance Imaging/Gadolinium-enhanced Vessel Wall Image after Bypass Surgery in Moyamoya Disease.

OBJECTIVE: After bypass surgery in patients with moyamoya disease, several changes on magnetic resonance imaging (MRI)/fluid attenuated inversion recovery (FLAIR) have been recognized, while findings on MRI/gadolinium-enhanced (Gd) vessel wall imaging (VWI) have never been reported. The purposes of this study were to investigate postoperative changes on MRI/Gd VWI and to clarify the relationship between the MRI/Gd VWI and MRI/FLAIR findings. METHODS: Consecutive patients who underwent bypass surgery at our hospital from September 2020 to March 2022 were candidates. RESULTS: In 20 patients with moyamoya disease, 25 operated hemispheres were investigated. In all hemispheres, hyperintensities in the cortical sulci on MRI/FLAIR and enhancement in the cortical sulci on MRI/Gd VWI appeared after bypass surgery. The maximum appearance of sulci enhancement on MRI/Gd VWI occurred earlier than the maximum appearance of the sulci hyperintensity on MRI/FLAIR, and this difference was significant (p = 0.001). CONCLUSIONS: MRI/Gd VWI demonstrated that the peak of the enhancement changes preceded the peak of hyperintensity changes on MRI/FLAIR. These MRI changes may reflect alterations in blood-brain barrier permeability after bypass surgery in patients with moyamoya disease.

Cerebrovascular Reserve Impairment in the Anterior Cerebral Artery Territory Predicts Deep Temporal Artery Enlargement After Combined Revascularization Surgery in Moyamoya Disease.

OBJECTIVE: A combined surgery of direct and indirect revascularization has been frequently performed in patients with moyamoya disease, though the efficacy of indirect revascularization surgery in adult patients with moyamoya disease has not been established. This study aimed to evaluate superficial temporal artery (STA) and deep temporal artery (DTA) diameters 1 day and 3 months after combined revascularization surgery in patients with moyamoya disease. We also investigated clinical factors related to DTA enlargement after surgery. METHODS: We examined 78 cerebral hemispheres in 57 adult and pediatric patients with moyamoya disease who underwent combined revascularization surgery [STA-MCA bypass and encephalo-duro-myo-synangiosis] in our institution. STA and DTA diameters were measured on axial magnetic resonance angiography images at 1 day and 3 months after surgery. RESULTS: DTA diameter increased in 64 hemispheres (82.1%). DTA diameter increase in association with STA diameter decrease was found in 39 hemispheres (50%). The proportion of hemispheres with a reduction in STA diameter was significantly higher in hemispheres with DTA enlargement than in hemispheres with DTA reduction (P = 0.0088). Among the 64 hemispheres with DTA enlargement, 51 (79.7%) showed cerebrovascular reserve (CVR) impairment in the anterior cerebral artery (ACA) territory before surgery. CVR impairment in the ACA territory was the only clinical factor related to DTA enlargement (P < 0.001). CONCLUSION: The DTA frequently enlarges after combined revascularization surgery, even in adult patients with moyamoya disease. In patients with impaired CVR in the ACA territory, blood supply from the DTA to the ACA territory can be expected after combined revascularization surgery.

Posterior Fossa Chronic Subdural Hematoma Associated with Supratentorial Chronic Subdural Hematoma.

OBJECTIVE: Chronic subdural hematoma (CSDH) in the posterior fossa has until now been reported in only 16 patients. This study clarified the frequency and characteristics of the posterior fossa CSDH through the use of magnetic resonance imaging (MRI) in patients with supratentorial CSDH. METHODS: We retrospectively examined presurgical MRI findings in patients with supratentorial CSDH who underwent surgery between 2006 and 2020. RESULTS: MRI revealed posterior fossa CSDH in 24 (7.3%) of 329 patients. Multivariable analyses demonstrated that anticoagulant treatment (P = 0.033, odds ratio [OR] 3.53), cerebrospinal fluid leak (P = 0.001, OR 18.5), and lack of previous trauma 3 weeks or more before admission (P = 0.027, OR 3.03) were risk factors of posterior fossa CSDH. Computed tomography could not show the hematomas in 20 patients (83.3%). All the posterior fossa CSDHs improved after supratentorial CSDH drainage. CONCLUSIONS: Posterior fossa CSDH was observed on MRI in a minority of patients with supratentorial CSDH. Although most patients with posterior fossa CSDH had good outcomes, large posterior fossa CSDH sometimes must be treated surgically, according to previous reports.

New-generation tyrosine kinase inhibitor-associated asymptomatic cerebrovascular stenosis: two illustrative cases.

New-generation tyrosine kinase inhibitors (TKIs), nilotinib and ponatinib, for chronic myelogenous leukemia (CML) have been reported to cause symptomatic cerebral ischemia. Herein, we report two patients with asymptomatic cerebral artery stenosis associated with these TKIs, as a previously unreported finding. Both patients were in their 40 s and administered new-generation TKIs without vascular risk factors. New-generation TKIs for CML can cause major cerebrovascular stenosis without any symptoms. Examining the neck and intracranial arteries using magnetic resonance angiography and carotid ultrasonography may prevent future cerebral infarctions associated with these TKIs.

Microcatheter Re-Shaping Using Fusion Image in Coil Embolization: A Technical Note.

Objective: We report the utility of microcatheter reshaping by referring to fusion images with 3D-DSA and microcatheter 3D images made using non-subtraction and non-contrast (non-SC) rotational images. Case Presentations: Case 1: The patient was a 74-year-old man who had an internal carotid-anterior choroidal artery bifurcation aneurysm with a tortuous proximal parent artery. The initial attempt to introduce the microcatheter into the aneurysm was unsuccessful. During this unsuccessful microcatheter introduction, we created fusion images with 3D-DSA and microcatheter 3D images by acquiring positional information of the microcatheter using the non-SC method. By reshaping the microcatheter with reference to the fusion images, the direction of the distal end of the microcatheter was reshaped to be in accordance with the long axis of the aneurysm, a shape more suitable for coiling. Case 2: The patient was a 47-year-old man who had an anterior communicating (A-com) artery aneurysm with two daughter sacs. We successfully placed two microcatheters in the direction of each sac to make more stable framing by referring to 3D fusion images after the first microcatheter was positioned. In both cases, microcatheter reshaping was necessary because of the vessel and aneurysm anatomy. We have used this technique successfully in 15 patients, for both ruptured and unruptured aneurysms. The average number of microcatheter reshaping was 1.3 times. Conclusion: This method provides effective microcatheter reshaping for coil embolization of aneurysms, particularly those with differences between the axis of the parent artery and the vertical axis of aneurysm, or with a tortuous proximal artery.

Diagnostic Tests for COVID-19 and Their Accuracy: Important Information for Physicians Caring for Patients with Stroke.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SAR-CoV-2), which appeared at the end of 2019 and has spread rapidly worldwide. In Japan, the increasing number of people infected with SAR-CoV-2 is also a cause of concern for physicians managing stroke patients. From the perspective of viral transmission in the hospital, stroke physicians must determine whether patients who have been transported by emergency have confirmed or suspected COVID-19. For this reason, stroke physicians must also understand about the characteristics and accuracy of the test for COVID-19 diagnosis. This article describes the sensitivity of the clinical symptoms, imaging investigations such as chest radiography and chest CT, and accuracy of nucleic-acid amplification tests and antigen tests used in the diagnosis of COVID-19. However, it should be noted that the accuracy of specimen tests may change depending on the collection site, timing, and method, because positive results in these tested specimens depend on the viral loads. In performing medical treatment for stroke, high accuracy and rapid inspection for COVID-19 is desired, but this is not currently available. For acute stroke treatment, such as thrombectomy, we recommend that these emergency patients, who are suspected of COVID-19 by clinical symptoms and image investigations, should be treated with implementation of strict infection control against droplets, contact, and airborne transmission until the most sensitive polymerase chain reaction test result is confirmed as negative.

Hemiparesis without Responsible Hematomas in Patients with Subarachnoid Hemorrhage Undergoing Early Aneurysmal Repair.

OBJECTIVE: The presence of hemiparesis on arrival in patients with subarachnoid hemorrhage (SAH) is presumed to affect prognosis; intracranial hematomas with mass effect responsible for hemiparesis are frequently observed in these patients. The aim of this study was to clarify characteristics and outcomes of patients who presented with hemiparesis on arrival with no responsible hematomas (hemiparesis without hematoma) having mass effect demonstrated on computed tomography. METHODS: Consecutive patients with SAH treated with surgery for ruptured cerebral aneurysms within 5 days of onset between 2003 and 2015 were retrospectively reviewed. RESULTS: Hemiparesis without hematoma was present in 25 of 858 surgically treated patients (2.9%). Internal carotid artery aneurysms were significantly more common in patients with hemiparesis without hematoma than in the other patients (P < 0.05). In 19 of 21 surviving patients (90.5%) with hemiparesis without hematoma on arrival, the hemiparesis improved at discharge. Favorable outcomes were achieved in 16 of 25 patients with hemiparesis without hematoma (64%) and in 13 of 59 patients with hemiparesis with hematomas (22.0%); this difference was significant (P < 0.05). CONCLUSIONS: Hemiparesis can be expected to improve in patients with SAH with hemiparesis without hematoma, and such patients appear to have a better prognosis than patients with SAH with hemiparesis and responsible hematomas. A possible major mechanism of hemiparesis without hematoma based on the characteristics identified is a combination of transient ipsilateral hemispheric functional failure caused by the impact of aneurysmal rupture and transient ischemia of the perforators originating from the internal carotid artery.

Selective Blocking Property of Microporous Polymer Membranes Fabricated by Chemical Vapor Deposition.

Poly-p-xylylene films have been utilized as protective and barrier layers for gases and solvents on electronic and implantable devices. Here we report a new approach to create highly permeable and selective nanofiltration membranes coated with microporous poly-p-xylylene nanofilms fabricated through a dry chemical vapor deposition process by using [2.2]paracyclophanes derivatives on ultrafiltration membranes. The introduction of crosslinking points into rigid poly-p-xylylenes enhanced microporosity and mechanical strength due to insufficient packing and depression of structural relaxation among polymer chains in three-dimensional networks. Crosslinked nanofilms with thicknesses down to 50 nm showed outstanding permeability for water and alcohols at a pressure difference of 0.5 MPa and exhibited higher rejection ratios for water-soluble organic dyes than non-crosslinked nanofilms. Poly-p-xylylene nanofilms also showed an excellent blocking property for non-polar organic solvent permeation through specific interaction of hydrophilic pores with organic solvents.