3D-visualization of segmented contacts of directional deep brain stimulation electrodes via registration and fusion of CT and FDCT.

Objectives: 3D-visualization of the segmented contacts of directional deep brain stimulation (DBS) electrodes is desirable since knowledge about the position of every segmented contact could shorten the timespan for electrode programming. CT cannot yield images fitting that purpose whereas highly resolved flat detector computed tomography (FDCT) can accurately image the inner structure of the electrode. This study aims to demonstrate the applicability of image fusion of highly resolved FDCT and CT to produce highly resolved images that preserve anatomical context for subsequent fusion to preoperative MRI for eventually displaying segmented contactswithin anatomical context in future studies.

Correlation of CT-based bone mineralization with drilling-force measurements in anatomical specimens is suitable to investigate planning of trans-pedicular spine interventions.

This interdisciplinary study examined the relationship between bone density and drilling forces required during trans-pedicular access to the vertebra using fresh-frozen thoraco-lumbar vertebrae from two female body donors (A, B). Before and after biomechanical examination, samples underwent high-resolution CT-quantification of total bone density followed by software-based evaluation and processing. CT density measurements (n = 4818) were calculated as gray values (GV), which were highest in T12 for both subjects (GV = 3483.

Pressure-Lowering Effect of Interventional Fistula Occlusion in Secondary Glaucoma due to Orbital Draining Intracerebral Fistulae.

Background: Carotid cavernous sinus fistulas (CSCF) are pathological connections of the internal and/or external carotid artery (and/or its branches) to the cavernous sinus. Ophthalmological symptoms and problems occur particularly when drainage is via the superior ophthalmic vein.

Material And Methods: Seven eyes of six patients with a high-grade suspicion of CSCF were included in this retrospective monocentric study.

Investigation of the functional pathogenesis of mild cognitive impairment by localisation-based locus coeruleus resting-state fMRI.

Dementia as one of the most prevalent diseases urges for a better understanding of the central mechanisms responsible for clinical symptoms, and necessitates improvement of actual diagnostic capabilities. The brainstem nucleus locus coeruleus (LC) is a promising target for early diagnosis because of its early structural alterations and its relationship to the functional disturbances in the patients. In this study, we applied our improved method of localisation-based LC resting-state fMRI to investigate the differences in central sensory signal processing when comparing functional connectivity (fc) of a patient group with mild cognitive impairment (MCI, n = 28) and an age-matched healthy control group (n = 29).

Diffusion Weighted Imaging in Gliomas: A Histogram-Based Approach for Tumor Characterization.

(1) Background: Astrocytic gliomas present overlapping appearances in conventional MRI. Supplementary techniques are necessary to improve preoperative diagnostics. Quantitative DWI via the computation of apparent diffusion coefficient (ADC) histograms has proven valuable for tumor characterization and prognosis in this regard.

Indirect Flow Diversion for Off-Centered Bifurcation Aneurysms and Distant Small-Vessel Aneurysms, a Retrospective Proof of Concept Study From Five Neurovascular Centers.

Treatment of cerebral aneurysms using hemodynamic implants such as endosaccular flow disruptors and endoluminal flow diverters has gained significant momentum during recent years. The intended target zone of those devices is the immediate interface between aneurysm and parent vessel. The therapeutic success is based on the reduction of aneurysmal perfusion and the subsequent formation of a neointima along the surface of the implant.

Mutations in Are a Novel Cause of Galloway-Mowat Syndrome.

Background: Galloway-Mowat syndrome (GAMOS) is characterized by neurodevelopmental defects and a progressive nephropathy, which typically manifests as steroid-resistant nephrotic syndrome. The prognosis of GAMOS is poor, and the majority of children progress to renal failure. The discovery of monogenic causes of GAMOS has uncovered molecular pathways involved in the pathogenesis of disease.

Impact of acetylsalicylic acid in patients undergoing cerebral aneurysm surgery - should the neurosurgeon really worry about it?

There has been an increase in the use of acetylsalicylic acid (ASA, Aspirin®) among patients with stroke and heart disease as well as in aging populations as a means of primary prevention. The potentially life-threatening consequences of a postoperative hemorrhagic complication after neurosurgical operative procedures are well known. In the present study, we evaluate the risk of continued ASA use as it relates to postoperative hemorrhage and cardiopulmonary complications in patients undergoing cerebral aneurysm surgery.

Rupture risk assessment for multiple intracranial aneurysms: why there is no need for dozens of clinical, morphological and hemodynamic parameters.

Introduction: A multitude of approaches have been postulated for assessing the risk of intracranial aneurysm rupture. However, the amount of potential predictive factors is not applicable in clinical practice and they are rejected in favor of the more practical PHASES score. For the subgroup of multiple intracranial aneurysms (MIAs), the PHASES score might severely underestimate the rupture risk, as only the aneurysm with the largest diameter is considered for risk evaluation.

Endovascular Treatment of Ruptured Middle Cerebral Artery Bifurcation Aneurysms. A Retrospective Observational Study of Short- and Long-Term Follow-Up.

Purpose: With the introduction of new devices and the development of approved devices, endovascular techniques are more and more considered as a treatment option for middle cerebral artery aneurysms (MCA). In this study, we present data on ruptured MCA aneurysms that were treated endovascularly in our hospital.

Material And Methods: In a retrospective case series of ruptured MCA bifurcation aneurysms, 118 (94%) cases were managed endovascularly between May 2008 and July 2017.

HoloInjection: augmented reality support for CT-guided spinal needle injections.

The correct placement of needles is decisive for the success of many minimally-invasive interventions and therapies. These needle insertions are usually only guided by radiological imaging and can benefit from additional navigation support. Augmented reality (AR) is a promising tool to conveniently provide needed information and may thus overcome the limitations of existing approaches.

In vivo anatomical mapping of human locus coeruleus functional connectivity at 3 T MRI.

The locus coeruleus (LC) is involved in numerous crucial brain functions and several disorders like depression and Alzheimer's disease. Recently, the LC resting-state functional connectivity (rs-fc) has been investigated in functional MRI by calculating the blood oxygen level-dependent (BOLD) response extracted using Montreal Neurological Institute (MNI) space masks. To corroborate these results, we aimed to investigate the LC rs-fc at native space by improving the identification of the LC location using a neuromelanin sensitive sequence.

Stent-assisted coiling of broad-necked intracranial aneurysms with a new braided microstent (Accero): procedural results and long-term follow-up.

Intracranial stents have expanded endovascular therapy options for intracranial aneurysms. The braided Accero stent is available for clinical use since May 2015. To date, no clinical reports on the stent are available.

Interactive exploration of a 3D intracranial aneurysm wall model extracted from histologic slices.

Purpose: Currently no detailed in vivo imaging of the intracranial vessel wall exists. Ex vivo histologic images can provide information about the intracranial aneurysm (IA) wall composition that is useful for the understanding of IA development and rupture risk. For a 3D analysis, the 2D histologic slices must be incorporated in a 3D model which can be used for a spatial evaluation of the IA's morphology, including analysis of the IA neck.

Acute symptomatic extracranial internal carotid occlusion - natural course and clinical impact.

To assess the vascular and clinical course of acute symptomatic extracranial internal carotid artery (ICA) occlusion. Patients with an acute ischemic event in the anterior circulation and corresponding extracranial ICA occlusion at CT angiography and/or color-coded duplex sonography underwent recurrent duplex follow-up for detection of spontaneous recanalization. Stroke recurrence and functional outcome 4.

Deployment of flow diverter devices: prediction of foreshortening and validation of the simulation in 18 clinical cases.

Purpose: Flow diverter (FD) devices show severe shortening during deployment in dependency of the vessel geometry. Valid information regarding the geometry of the targeted vessel is therefore mandatory for correct device selection, and to avoid complications. But the geometry of diseased tortuous intracranial vessels cannot be measured accurately with standard methods.

Resolution of Brainstem Edema after Neurosurgical Occlusion of Dural Arteriovenous Fistulas of the Craniocervical Junction: Report of Three Cases and Review.

Objective:  Dural arteriovenous fistulas of the craniocervical junction are rare but the most dangerous of spinal fistulas. The concurrent brainstem edema has been attributed to increased pressure within the venous outflow of the brainstem and upper cord, but the differential diagnosis of brainstem edema is demanding. This report presents the details of clinical findings, magnetic resonance imaging (MRI) , surgical techniques, and follow-up of these fistulas.

Determination and verification of the x-ray spectrum of a CT scanner.

The accuracy of Monte Carlo (MC) simulations in estimating the computed tomography radiation dose is highly dependent on the proprietary x-ray source information. To address this, this study develops a method to precisely estimate the x-ray spectrum and bowtie (BT) filter thickness of the x-ray source based on physical measurements and calculations. The static x-ray source of the CT localizer radiograph was assessed to measure the total filtration at the isocenter for the x-ray spectrum characterization and the BT profile (air-kerma values as a function of fan angle).

Regional Differences in Thrombectomy Rates : Secondary use of Billing Codes in the MIRACUM (Medical Informatics for Research and Care in University Medicine) Consortium.

Background And Purpose: Mechanical thrombectomy, in addition to intravenous (i.v.) thrombolysis is recommended for treatment of acute stroke in patients with large vessel occlusions (LVO) in the anterior circulation up to 6 h after symptom onset.

Bringing hemodynamic simulations closer to the clinics: a CFD prototype study for intracranial aneurysms.

Computational Fluid Dynamics enables the investigation of patient-specific hemodynamics for rupture predictions and treatment support of intracranial aneurysms. However, due to numerous simplifications to decrease the computations effort, clinical applicability is limited until now. To overcome this situation a clinical research software prototype was tested that can be easily operated by attending physicians.

Comparison of gesture and conventional interaction techniques for interventional neuroradiology.

Purpose: Interaction with radiological image data and volume renderings within a sterile environment is a challenging task. Clinically established methods such as joystick control and task delegation can be time-consuming and error-prone and interrupt the workflow. New touchless input modalities may have the potential to overcome these limitations, but their value compared to established methods is unclear.

Mathematical 3D modelling and sensitivity analysis of multipolar radiofrequency ablation in the spine.

Radiofrequency ablation is a valuable tool in the treatment of many diseases, especially cancer. However, controlled heating up to apoptosis of the desired target tissue in complex situations, e.g.

An automatic CFD-based flow diverter optimization principle for patient-specific intracranial aneurysms.

The optimal treatment of intracranial aneurysms using flow diverting devices is a fundamental issue for neuroradiologists as well as neurosurgeons. Due to highly irregular manifold aneurysm shapes and locations, the choice of the stent and the patient-specific deployment strategy can be a very difficult decision. To support the therapy planning, a new method is introduced that combines a three-dimensional CFD-based optimization with a realistic deployment of a virtual flow diverting stent for a given aneurysm.