Next-Generation Exoscopic Surgery Featuring a Head-Mounted 3-Dimensional Display for Carotid Endarterectomy: 2-Dimensional Operative Video.

Recent advancements in medical equipment have led to the use of exoscopes in neurosurgery, thereby replacing conventional operating microscopes.1,2 These devices enable surgeons to work comfortably, even in situations requiring a tilted visual axis, and their effectiveness in carotid endarterectomy (CEA) for carotid artery stenosis has been reported.3,4 However, the placement of 3-dimensional (3D) monitoring devices is challenging.3,4 To address this issue, we present a case in which CEA was performed using ORBEYE with a 3D head-mounted display. This device allows continuous 3D observation of the surgical field on the preocular screen. Case: A 79-year-old man who had undergone chemoradiotherapy for left maxillary cancer 5 years earlier was referred to our department to undergo treatment for left internal carotid artery stenosis. Computed tomography angiography revealed severe left internal carotid artery stenosis with hypoechoic vulnerable plaques on carotid ultrasound. Carotid artery stenting was considered to be a better option than CEA. However, CEA yields better outcomes, especially in patients with vulnerable soft plaques.5 Left CEA was performed using ORBEYE with a 3D head-mounted display (HOGY Medical Co., Ltd.). The procedure was successfully performed under the observation of the head-mounted display, from skin incision to closure. Postoperatively, the patient had no neurological deficits but experienced transient hoarseness. Using an exoscope under the guidance of a head-mounted display represents a next-generation surgical technique that overcomes the limitations of traditional exoscopic surgery. The patient consented to the procedure, and the participants and any identifiable individuals consented to publication of his/her image. Our institutional review board approved this publication (#B230184).

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. Patients with tandem ACICAO were analyzed in this study. Procedures, recanalization rates, complications, and prognoses were evaluated. RESULTS: Ten patients (6%) of all 154 patients had ACICAO. In nine (90%) of the 10 patients, cervical lesions were successfully crossed and intervened upon. Four patients underwent stenting and five underwent angioplasty alone, followed by intracranial procedure. Eight patients (80%) achieved successful recanalization following mechanical thrombectomy for intracranial occlusion. However, one patient had massive subarachnoid hemorrhage during the procedure and another patient developed massive intracranial hemorrhage after EVT, both after stenting. Four of the five patients who initially underwent angioplasty alone subsequently underwent staged endarterectomy or stenting for residual stenosis on or after the next day. The single patient in whom the cervical lesion could not be crossed and another with reocclusion after EVT underwent a rescue bypass procedure due to persistent ischemic symptoms. After 90 days, four patients (40%) were functionally independent (modified Rankin scale score 0-2). CONCLUSIONS: Our experience suggests that EVT for ACICAO is technically feasible; however, it involves the potential risk of several significant complications. To avoid serious hemorrhagic complications, cervical lesions may be better treated with angioplasty alone first.

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. Electron-beam irradiation caused layer-by-layer dissolution of PbS at the interface, resulting in the formation of the Pb nanodroplet. Ordered liquid layers were observed adjacent to the interface even under continuous electron-beam irradiation and followed the movement of the interface. Instantaneous epitaxial growth of PbS was observed as a reverse process of the dissolution. The resultant Pb nanodroplet provides indisputable evidence for selective sputtering of sulfur atoms via electron-beam irradiation. This paper demonstrates atomic resolution in situ observations of selective and complete sputtering. The observed dynamics can be explained by the intermittent phase transition via nonequilibrium states of the solid-liquid nanointerface triggered by selective sputtering.

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. Seven days later, she was admitted to our hospital with sudden disturbance of consciousness. CT revealed SAH and CTA demonstrated dilatation of the right vertebral artery (VA). The dilated lesion with an intimal flap on the right VA proximal to the posterior inferior cerebellar artery was confirmed on DSA. The dilated lesion and the proximal VA were occluded endovascularly using coils. The condition of the patient improved gradually, and she was transferred to the rehabilitation hospital on day 45 with a modified Rankin Scale score of 2. Conclusion: The clinical course of the presented case, although rare, should be kept in mind in daily clinical practice.

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. CT demonstrated intracerebral hematoma in the left frontal lobe and subarachnoid hemorrhage. On CTA and MRA, a DAVF was found in the left laterocavernous sinus region associated with the accessory meningeal artery (AMA) and draining directly into the superficial middle cerebral vein. The diagnosis was confirmed by DSA, which revealed a DAVF fed by the large and straight AMA and the internal carotid artery's meningohypophyseal trunk. Endovascular transarterial venous coil embolization was performed through the AMA. A microcatheter was advanced beyond the shunt point into the origin of the draining vein, and coils were placed in the venous and arterial sides of the fistula. The fistula was completely occluded, and 15-month follow-up angiography demonstrated stable obliteration of the fistula. Conclusion: Transarterial venous coil embolization may be a treatment option for non-sinus-type laterocavernous sinus DAVF with a large fistula size and a large and straight feeding artery.

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 (0.8%). In this report, we described these 2 cases that were rescued through emergent stenting. Mechanical thrombectomy, using both a stent retriever and an aspiration catheter, was performed for acute middle cerebral artery M2 occlusion in Patient 1 (a 69-year-old man) and for distal M1 occlusion in Patient 2 (an 83-year-old woman). In both cases, recanalization was achieved with the procedure, but irregular stenosis developed at the initially nonoccluded, but mildly arteriosclerotic, M1, after recanalization. During the thrombectomy procedure, the aspiration catheter sifted up to the arteriosclerotic M1. In both cases, the lesions were considered vessel dissection, due to a shift of the aspiration catheter tip into the arteriosclerotic vessel wall. Repeated percutaneous angiography with antithrombotic therapy failed to improve the lesions and to maintain the antegrade blood flow. Finally, lesions in each patient were successfully rescued through the use of emergent stenting. A drug-eluting stent for coronary use was deployed in Patient 1, and an Enterprise stent was applied in Patient 2. Inadvertent shift of the aspiration catheter into arteriosclerotic vessels can cause a serious intracranial vessel dissection. When performing mechanical thrombectomy, intracranial stents need to be available as rescue treatment devices to manage refractory iatrogenic intracranial vessel dissection.

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. Epitaxial SrVO3 films are topochemically converted to anion-deficient oxynitrides by ammonia treatment, where the direction or periodicity of defect planes is altered depending on the substrate employed, unlike the known change in crystal orientation. First-principles calculations verified its biaxial strain effect. Like oxide heterostructures, the oxynitride has a superlattice of insulating and metallic blocks. Given the abundance of perovskite families, this study provides new opportunities to design superlattices by chemically modifying simple perovskite oxides with tunable anion-vacancy patterns through epitaxial lattice strain.

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. This technique can be an alternative option in selected patients, especially those allergic to the contrast medium.

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. This technique, therefore, reduces the amount of contrast medium and enables one to perform coil embolization safely.

Two-Dimensional Perovskite Oxynitride K2 LaTa2 O6 N with an H+ /K+ Exchangeability in Aqueous Solution Forming a Stable Photocatalyst for Visible-Light H2 Evolution.

Undoped layered oxynitrides have not been considered as promising H2 -evolution photocatalysts because of the low chemical stability of oxynitrides in aqueous solution. Here, we demonstrate the synthesis of a new layered perovskite oxynitride, K2 LaTa2 O6 N, as an exceptional example of a water-tolerant photocatalyst for H2 evolution under visible light. The material underwent in-situ H+ /K+ exchange in aqueous solution while keeping its visible-light-absorption capability. Protonated K2 LaTa2 O6 N, modified with an Ir cocatalyst, exhibited excellent catalytic activity toward H2 evolution in the presence of I- as an electron donor and under visible light; the activity was six times higher than Pt/ZrO2 /TaON, one of the best-performing oxynitride photocatalysts for H2 evolution. Overall water splitting was also achieved using the Ir-loaded, protonated K2 LaTa2 O6 N in combination with Cs-modified Pt/WO3 as an O2 evolution photocatalyst in the presence of an I3 - /I- shuttle redox couple.

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. Although its radiological findings were compatible with an ABC, rotational digital subtraction angiography revealed that this osteolytic lesion was a large middle meningeal artery (MMA) aneurysm. To release the compression force on the optic nerve and confirm the diagnosis, we performed endovascular embolization, followed by surgical removal of the lesion. Histologic examination revealed that the resected lesion met the requirements of a thrombosed aneurysm. No new neurologic deficits appeared after the surgery, and no symptomatic recurrence have been noted during the 6-month follow-up. CONCLUSIONS: This is the first case report to show that ABC-like lesions in patients with FD could be thrombosed MMA aneurysms. It is thus possible that some lesions previously diagnosed as ABCs were thrombosed MMA aneurysms or included a thrombosed MMA aneurysm. It is therefore important to rule out the presence of a MMA aneurysm when we encounter what appears to be an ABC in the presence of FD.

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., the Z contrast in textbooks and papers. Here we first demonstrate the deviation from the power-law model by quantitative experiments of a few 2D materials (graphene, MoS2 and WS2 monolayers). Then we elucidate ADF signal of single atoms using simulations to clarify the cause of the deviation. Two major causes of the deviation from the power-law model will be pointed out. The present study provides a practical guideline for the usage of the conventional power-law model for ADF imaging.

Undoped Layered Perovskite Oxynitride Li2 LaTa2 O6 N for Photocatalytic CO2 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 Li2 LaTa2 O6 N with a layered perovskite structure was successfully prepared by thermal ammonolysis of a lithium-rich oxide precursor. Li2 LaTa2 O6 N exhibited high crystallinity and visible-light absorption up to 500 nm. As opposed to well-known 3D oxynitride perovskites, Li2 LaTa2 O6 N supported by a binuclear RuII complex was capable of stably and selectively converting CO2 into formate under visible light (λ>400 nm). Transient absorption spectroscopy indicated that, as compared to 3D oxynitrides, Li2 LaTa2 O6 N possesses a lower density of mid-gap states that work as recombination centers of photogenerated electron/hole pairs, but a higher density of reactive electrons, which is responsible for the higher photocatalytic performance of this layered oxynitride.

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. The quantitative STEM images revealed an inhomogeneous dye-molecule distribution at the early stage of its absorption, i.e., the aggregation of the dye molecules. The majority of the titania surface was not covered by dye molecules, suggesting that optimization of the dye molecule distribution could yield further improvement of the DSC conversion efficiencies.

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. Furthermore, to reduce image distortion and shot noises in experimental images, multiple acquisitions with drift correction were performed, and the atomic ADF contrast was quantitatively acquired. To reproduce the experimental ADF contrast, we used three distribution functions as the effective source distribution in simulations. The optimum distribution function and its full-width at half-maximum were evaluated by measuring the residuals between the experimental and simulated images. It was found that the experimental images could be explained well by a linear combination of a Gaussian function and a Lorentzian function with a longer tail than the Gaussian function.

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. We applied the procedure for observation of a graphene specimen with 1-4 layers. The inner and outer angles of an ADF detector, which are important parameters in quantitative analyses, were precisely measured. The quantitative contrast of ADF images was in agreement with that of simulated images, and the quantitative ADF imaging allowed us to directly count the number of graphene layers.