Predicting impaired cerebrovascular reactivity and risk of hyperperfusion syndrome in carotid artery stenosis using BeamSAT magnetic resonance imaging.

Pencil-beam presaturation (BeamSAT) magnetic resonance imaging (MRI) produces selective magnetic resonance angiography (MRA) images of specific arteries, including the unilateral internal carotid artery (ICA-selective MRA) or vertebral artery (VA-selective MRA). We evaluate the influence of flow pattern, visualized using BeamSAT MRI, on preoperative cerebral hemodynamic status and postoperative hyperperfusion syndrome (HPS). Patients undergoing carotid artery stenting or carotid endarterectomy were categorized into two groups to evaluate flow pattern.

Atomic-Scale Dynamics at Solid-Liquid Nanointerfaces Induced by Electron-Beam Irradiation.

We report electron-beam induced dynamics at PbS-Pb solid-liquid interfaces. We fabricated PbS-Pb solid-liquid nanointerfaces by heating PbS nanocrystals under vacuum to observe the entire process of structural evolution at the atomic scale. We investigated the dynamics using time-resolved high-angle annular dark-field imaging.

Endovascular Treatment of Tandem Atherosclerotic Cervical Internal Carotid Artery Occlusion in the Setting of Acute Ischemic Stroke.

Background: Among tandem occlusions, atherosclerotic cervical internal carotid artery occlusion (ACICAO) can be technically challenging and associated with its unique complications. We evaluated our experience with endovascular treatment (EVT) of ACICAO in the setting of acute ischemic stroke.

Methods: In total, 154 consecutive patients who underwent EVT for acute anterior circulation stroke at our institute were retrospectively reviewed.

Non-Sinus-Type Laterocavernous Sinus Dural Arteriovenous Fistula Treated by Transarterial Venous Coil Embolization: A Case Report.

Objective: Laterocavernous sinus dural arteriovenous fistulas (DAVFs) are rare and not always accessible transvenously due to their angioarchitecture. We report a case of non-sinus-type laterocavernous sinus DAVF treated by endovascular transarterial venous coil embolization.

Case Presentation: A 78-year-old woman was admitted to our hospital with loss of consciousness, right hemiparesis, and motor aphasia.

A Case of Intracranial Vertebral Artery Dissection Undetected by CT, MRI, and MRA at the Onset of Headache That Caused Subarachnoid Hemorrhage Seven Days Later.

Objective: We report a patient with normal imaging findings at the onset of preceding headache who developed subarachnoid hemorrhage (SAH) due to intracranial vertebral artery dissection 7 days later.

Case Presentation: A 51-year-old woman with a history of chronic headache visited our emergency outpatient department with a complaint of mild to moderate right nuchal pain. CT, MRA, and MRI (diffusion-weighted image, T2-weighted image, FLAIR, MR cisternography, and basi-parallel anatomical scanning) were normal.

Iatrogenic intracranial vessel dissection during mechanical thrombectomy rescued by emergent stenting: 2 case reports.

Intracranial vessel dissection is a procedural complication associated with endovascular treatment. However, there have been few reports on its potential causes and management during mechanical thrombectomy. In approximately 250 cases of mechanical thrombectomy over the past 5 years at our institution, iatrogenic intracranial dissection occurred in 2 patients (0.

Strain-induced creation and switching of anion vacancy layers in perovskite oxynitrides.

Perovskite oxides can host various anion-vacancy orders, which greatly change their properties, but the order pattern is still difficult to manipulate. Separately, lattice strain between thin film oxides and a substrate induces improved functions and novel states of matter, while little attention has been paid to changes in chemical composition. Here we combine these two aspects to achieve strain-induced creation and switching of anion-vacancy patterns in perovskite films.

Ultrasonographically-guided stent placement at the vertebral artery origin without contrast medium: A case report.

Although ultrasonographically-guided carotid interventions without contrast medium have been reported in the literature, we found no report regarding stenting of the vertebral artery origin for treatment of stenosis. Here, we report the case of an iodine-allergic patient in whom a stenosis at the origin of the vertebral artery was successfully treated with ultrasonographically-guided stent placement without contrast medium. B-mode longitudinal images were monitored during the insertion of the embolism-protection device, when positioning the stent, and for the evaluation of the stent opening.

Microcatheter injection reduces the amount of contrast medium during middle cerebral artery aneurysm embolization in a patient with chronic kidney disease.

We describe a unique technique to reduce the amount of contrast medium by injecting diluted contrast medium from the microcatheter during neurointervention. A patient with severe renal impairment due to polycystic kidney was referred for endovascular surgery for wide-neck middle cerebral artery aneurysm. In order to reduce the amount of contrast medium, contrast medium was injected from the microcatheter placed in the middle cerebral artery during coil embolization; renal function decline was not observed after the procedure.

Thrombosed Middle Meningeal Artery Aneurysms Mimicking Aneurysmal Bone Cysts in a Patient with Fibrous Dysplasia.

Background: The aneurysmal bone cyst (ABC) is a rare osteolytic lesion that is often associated with osseous disease such as fibrous dysplasia (FD).

Case Description: A 66-year-old woman previously diagnosed with FD presented with suddenly reduced visual acuity. Computed tomography and magnetic resonance imaging revealed a large osteolytic lesion in the middle cranial fossa that had invaded the left orbit.

Atomic number dependence of Z contrast in scanning transmission electron microscopy.

Annular dark-field (ADF) imaging by scanning transmission electron microscopy (STEM) is a common technique for material characterization with high spatial resolution. It has been reported that ADF signal is proportional to the nth power of the atomic number Z, i.e.

Undoped Layered Perovskite Oxynitride Li LaTa O N for Photocatalytic CO Reduction with Visible Light.

Oxynitrides are promising visible-light-responsive photocatalysts, but their structures are almost confined with three-dimensional (3D) structures such as perovskites. A phase-pure Li LaTa O N with a layered perovskite structure was successfully prepared by thermal ammonolysis of a lithium-rich oxide precursor. Li LaTa O N exhibited high crystallinity and visible-light absorption up to 500 nm.

Microscopic observation of dye molecules for solar cells on a titania surface.

The lateral distribution and coverage of Ru-based dye molecules, which are used for dye-sensitized solar cells (DSCs), were directly examined on a titania surface using high-resolution scanning transmission electron microscopy (STEM). The clean surface of a free-standing titania nanosheet was first confirmed with atomic resolution, and then, the nanosheet was used as a substrate. A single dye molecule on the titania nanosheet was visualized for the first time.

Quantitative annular dark-field imaging of single-layer graphene-II: atomic-resolution image contrast.

We have investigated how accurately atomic-resolution annular dark-field (ADF) images match between experiments and simulations to conduct more reliable crystal structure analyses. Quantitative ADF imaging, in which the ADF intensity at each pixel represents the fraction of the incident probe current, allows us to perform direct comparisons with simulations without the use of fitting parameters. Although the conventional comparison suffers from experimental uncertainties such as an amorphous surface layer and specimen thickness, in this study we eliminated such uncertainties by using a single-layer graphene as a specimen.

Quantitative annular dark-field imaging of single-layer graphene.

A quantification procedure for annular dark-field (ADF) imaging, in which a quantitative contrast is given as a scattering intensity normalized by an incident probe current, is presented. The obtained ADF images are converted to quantitative ADF images using an empirical equation, which is a function of an ADF imaging system setting. The quantification procedure fully implements the nonlinear response of the ADF imaging system, which is critical in high-sensitivity observation.