Temperature-Dependent Structural and Optoelectronic Properties of the Layered Perovskite 2-Thiophenemethylammonium Lead Iodide.

Improved knowledge of the influence of temperature upon layered perovskites is essential to enable perovskite-based devices to operate over a broad temperature range and to elucidate the impact of structural changes upon the optoelectronic properties. We examined the Ruddlesden-Popper layered perovskite 2-thiophenemethylammonium lead iodide (ThMAPbI) and observed a structural phase transition between a high- and a low-temperature phase at 220 K using temperature-dependent X-ray diffraction, UV-visible absorption, and photoluminescence (PL) spectroscopy. The structural phase transition altered the tilt pattern of the inorganic octahedra layer, modifying the absorption and PL spectra.

Pediatric Interventional Neuroradiology: "How I Do It" v. I - Diagnostic Angiography.

Pediatric neurointervention differs from the adult in several important respects. Here we describe a modern approach to readily acquire diagnostic quality images of children. Preparation, access, angiogragraphy and closure have evolved along with new knowledge and technology.

Multi-pixel photoconductive emitters for the controllable generation of azimuthal and radial terahertz beams.

A multi-pixel photoconductive emitter is reported that generates THz beams with either azimuthal, radial or linear polarization states. Switching between the different polarization states was purely electrical, via the bias voltage applied, circumventing the need for mechanical polarization optics or different THz emitters to change the polarization. Dipole array modelling was performed to validate emitter array designs, and to explore their optimal bias configuration, while spatially-resolved electro-optic detection of the generated beams confirmed that cylindrical-vector beams were produced.

New ischemic lesions on brain magnetic resonance imaging in patients with blunt traumatic cerebrovascular injury.

Background: Patients with blunt cerebrovascular injuries are at risk of thromboembolic stroke. Although primary prevention with antithrombotic therapy is widely used in this setting, its effectiveness is not well defined and requires further investigation. The aim of this study was to evaluate the utility of magnetic resonance imaging (MRI)-detected ischemic brain lesions as a possible future outcome for randomized clinical trials in this patient population.

Whole blood aggregometry prior to Pipeline embolization device treatment of intracranial aneurysms: defining an optimal platelet inhibition cutoff value for clopidogrel.

Objective: Dual antiplatelet therapy is required for the treatment of intracranial aneurysms with the Pipeline embolization device (PED). Platelet function testing (PFT) is often used to assess the efficacy of the antiplatelet regimen prior to PED placement. The optimal impedance values for whole blood aggregometry in this setting have not been defined.

Intra-arterial vasodilators for vasospasm following aneurysmal subarachnoid hemorrhage: a meta-analysis.

Objective: The efficacy of intra-arterial vasodilators (IADs) for the treatment of vasospasm following aneurysmal subarachnoid hemorrhage (aSAH) remains debatable. The objective of this meta-analysis was to pool estimates of angiographic and neurological response, clinical outcome, and mortality following treatment of vasospasm with IADs.

Methods: We searched PubMed, Embase, Scopus, Clinicaltrials.

Reliability assessment of the Biffl Scale for blunt traumatic cerebrovascular injury as detected on computer tomography angiography.

OBJECTIVE Blunt traumatic cerebrovascular injury (TCVI) represents structural injury to a vessel due to high-energy trauma. The Biffl Scale is a widely accepted grading scheme for these injuries that was developed using digital subtraction angiography. In recent years, screening CT angiography (CTA) has been used to identify patients with TCVI.

Optical coherence tomography of traumatic aneurysms of the internal carotid artery: report of 2 cases.

The pathophysiology of extracranial traumatic aneurysm formation has not been fully elucidated. Intraarterial optical coherence tomography (OCT), an imaging modality capable of micrometer cross-sectional resolution, was used to evaluate patients presenting with saccular traumatic aneurysms of the internal carotid artery (ICA). Two consecutive trauma patients diagnosed with saccular traumatic aneurysms of the cervical ICA, per the institutional screening protocol for traumatic cerebrovascular injury, underwent digital subtraction angiography (DSA) with OCT.

Clinical Presentation, Imaging, and Management of Complications due to Neurointerventional Procedures.

Neurointervention is a rapidly evolving and complex field practiced by clinicians with backgrounds ranging from neurosurgery to radiology, neurology, cardiology, and vascular surgery. New devices, techniques, and clinical applications create exciting opportunities for impacting patient care, but also carry the potential for new iatrogenic injuries. Every step of every neurointerventional procedure carries risk, and a thorough appreciation of potential complications is fundamental to maximizing safety.

Carotid and vertebral injury study (CAVIS) technique for characterization of blunt traumatic aneurysms with reliability assessment.

Traumatic aneurysms occur in up to 20% of blunt traumatic extracranial carotid artery injuries. Currently there is no standardized method for characterization of traumatic aneurysms. For the carotid and vertebral injury study (CAVIS), a prospective study of traumatic cerebrovascular injury, we established a method for aneurysm characterization and tested its reliability.

Endovascular tools available for the treatment of cerebrovascular disease.

This article reviews essential neurointerventional tools approved in the United States, including catheters and wires, coils, flow diverters, balloons, stents, and devices for mechanical thrombectomy and thrombolysis. These devices are the result of decades of technical development; this article will also briefly trace the evolution of these devices, with an emphasis on the most influential developments.

Resolution of diminished olfactory sensation after treatment of bilateral ophthalmic segment aneurysms with flow diversion: case report.

Background And Importance: Olfactory tract dysfunction due to an unruptured intracranial aneurysm is rare. We present a case in which a patient with impaired olfaction related to bilateral internal carotid artery aneurysms experienced subjective and quantitative objective improvement of olfactory sensation after treatment of ophthalmic segment aneurysms with flow diversion.

Clinical Presentation: A 44-year-old woman presented with hyposmia and bilateral ophthalmic segment internal carotid artery aneurysms.

Improved diagnosis of actively bleeding aneurysm on CT angiography using delayed CT images.

Computed tomographic angiography (CTA) is being increasingly utilized in the non-invasive diagnosis of aneurysmal subarachnoid hemorrhage (SAH). There are emerging reports of diagnosis of active aneurysmal bleeding on CTA, furthering our understanding of imaging features of active extravasation on cross-sectional studies. We demonstrate imaging characteristics of two such cases of active contrast extravasation from intracranial aneurysms.

Clinical experience with Matrix2 360 degrees coils in the treatment of 100 intracranial aneurysms.

Background: The M2-360 degrees is a recent class of aneurysm coil. This device combines the second generation of bioactive copolymer coating, which is intended to promote aneurysm fibrosis, with the "360 degrees " design, which is meant to improve uniformity and density of packing. This study evaluates the safety and angiographic stability of these devices.

Legacy and current understanding of the often-misunderstood Foix-Alajouanine syndrome. Historical vignette.

Foix-Alajouanine syndrome has become a well-known entity since its initial report in 1926. The traditional understanding of this clinical syndrome is as a progressive spinal cord venous thrombosis related to a spinal vascular lesion, resulting in necrotic myelopathy. However, spinal venous thrombosis is extremely rare and not a feature of any common spinal vascular syndrome.

Perfusion CT measurements in healthy cervical spinal cord: feasibility and repeatability of the study as well as interchangeability of the perfusion estimates using two commercially available software packages.

Our purpose was to examine the feasibility and reproducibility of perfusion CT studies in the cervical spinal cord and the interchangeability of the values obtained by two post-processing methods. The perfusion CT studies of 40 patients with neck tumours were post-processed using two software packages (Software-1: deconvolution-based analysis with adiabatic tissue homogeneity approach and Software-2: maximum-slope-model with Patlak analysis). Eight patients were examined twice for assessing the reproducibility of the technique.

Carotid cavernous fistula in CNS choriocarcinoma.

Carotid artery-cavernous sinus fistulas (CCFs) are infrequently reported in the pediatric population, and are rarely reported in conjunction with CNS neoplasms. The authors present a 7-year-old girl with CNS choriocarcinoma who acutely developed left eye proptosis and conjunctival injection. Computed tomography angiography revealed a CCF, which was endovascularly embolized with detachable coils.

Intravenously administered abciximab in the management of early cerebral ischemia after carotid endarterectomy: case report.

Objective And Importance: Cerebral ischemia is the most worrisome perioperative complication of carotid endarterectomy (CEA). The stroke rate occurring with CEA is estimated to range from 2.3 to 6.

Ocular ischemic syndrome after occlusion of both external carotid arteries.

The ocular ischemic syndrome (OIS) has been reported in association with high-grade stenosis or occlusion of the common carotid artery (CCA) or internal carotid artery (ICA) but never with high-grade stenosis or occlusion of the external carotid artery (ECA) alone. We describe two patients who developed OIS with bilateral occlusion of the ECAs yet patent CCAs and ICAs. In one case, unilateral OIS followed consecutive bilateral carotid endarterectomies.

Percutaneous ethanol sclerotherapy for vascular malformations in the head and neck.

Vascular malformations are frequent in the head and neck. In addition to the occasional devastating cosmetic effects of large vascular malformations, some may cause significant functional impairment by encroaching on the eye, tongue, or throat. Large lesions may produce a breakdown of skin or mucosa, with resultant leakage of blood or fluid and possible infection in the lesions and surrounding tissues.

Perfusion CT for head and neck tumors: pilot study.

Background And Purpose: Differentiation of malignant from benign head and neck lesions is often very difficult on imaging studies, especially in patients with treated cancer. We evaluated the feasibility and reproducibility of perfusion CT (CTP) after enhanced head and neck CT and attempted to differentiate benign from malignant processes.

Methods: CTP was attempted in 17 patients after head and neck contrast-enhanced CT.

Ophthalmic artery occlusion secondary to radiation-induced vasculopathy.

A 35-year-old man with neurofibromatosis type 1 (NF1) had a left ophthalmic artery occlusion that caused no light perception OS 28 years after having been treated with external beam radiation therapy for a presumed glioma of the right optic nerve and chiasm. Clinical and imaging findings were consistent with radiation-induced cerebral vasculopathy. This ophthalmic complication has never been reported, despite the common occurrence of severe carotid-ophthalmic artery junction stenosis after radiation in NF1 patients.

Facial and trigeminal neuropathies in cavernous sinus fistulas.

Three patients with carotid-cavernous fistulas had prominent ipsilateral facial nerve neuropathy. One patient also had ipsilateral third division trigeminal neuropathy, manifesting as painful trismus and lower facial numbness. Rarely reported in carotid-cavernous fistula, these neuropathies may occur when there is substantial drainage of the fistula into a dilated inferior petrosal sinus.