Johannes Weber

Klinik Hirslanden · Neuroradiology

Purpose To systematically analyse the time course of vessel wall enhancement and associated stenosis in patients with primary angiitis of the central nervous system (PACNS) following immunosuppressive therapy. Material and methods Two neuroradiologists retrospectively analysed MRIs of patients with PACNS seen at the Bern University Hospital and th...

Background and Objectives Progression independent of relapse activity (PIRA) is a crucial determinant of overall disability accumulation in multiple sclerosis (MS). Accelerated brain atrophy has been shown in patients experiencing PIRA. In this study, we assessed the relation between PIRA and neurodegenerative processes reflected by (1) longitudina...

Background: Detecting new and enlarged lesions in multiple sclerosis (MS) patients is needed to determine their disease activity. LeMan-PV is a software embedded in the scanner reconstruction system of one vendor, which automatically assesses new and enlarged white matter lesions (NELs) in the follow-up of MS patients; however, multicenter validat...

Purpose To evaluate and compare which factors are relevant to the diagnostic decision-making and imaging workup of intracerebral hemorrhages in large, specialized European centers. Methods Expert neuroradiologists from ten large, specialized centers (where endovascular stroke treatment is routinely performed) in nine European countries were select...

Background: Very small anterior communicating artery aneurysms (vsACoA) of <5 mm in size are detected in a considerable number of patients with aneurysmal subarachnoid hemorrhage (aSAH). Single-center studies report that vsACoA harbor particular risks when treated. Objective: To assess the clinical and radiological outcome(s) of patients with aS...

Background Whether thrombectomy alone is equally as effective as intravenous alteplase plus thrombectomy remains controversial. We aimed to determine whether thrombectomy alone would be non-inferior to intravenous alteplase plus thrombectomy in patients presenting with acute ischaemic stroke. Methods In this multicentre, randomised, open-label, bl...

Importance: The mechanisms driving neurodegeneration and brain atrophy in relapsing multiple sclerosis (RMS) are not completely understood. Objective: To determine whether disability progression independent of relapse activity (PIRA) in patients with RMS is associated with accelerated brain tissue loss. Design, setting, and participants: In th...

BACKGROUND: Endovascular treatment in large artery occlusion stroke reduces disability. However, the impact of anesthesia type on clinical outcomes remains uncertain. METHODS: We compared consecutive patients in the Swiss Stroke Registry with anterior circulation stroke receiving endovascular treatment with or without general anesthesia (GA). The p...

Introduction Rapid treatment of acute ischemic stroke (AIS) depends on sufficient staffing which differs between Stroke Centers and Stroke Units in Switzerland. We studied the effect of admission time on performance measures of AIS treatment and related temporal trends over time. Patients and methods We compared treatment rates, door-to-image-time...

Background In contrast to conventional CT perfusion (CTP) imaging, flat panel detector CT perfusion (FD-CTP) imaging can be acquired directly in the angiosuite. Objective To evaluate time-resolved whole brain FD-CTP imaging and assess clinically important qualitative and quantitative perfusion parameters in correlation with previously acquired con...

Background Endovascular treatment in large artery occlusion stroke reduces disability. However, the impact of anesthesia type on clinical outcomes remains uncertain. Methods We compared consecutive patients in the Swiss Stroke Registry with anterior circulation stroke receiving endovascular treatment with or without general anesthesia (GA). The pr...

Introduction: In acute ischemic stroke, perfusion imaging facilitates detection of the occluded vessels, influences decision-making regarding therapy options, and is recommended especially in delayed time windows. In contrast to conventional CT perfusion (CTP), flat panel detector CT perfusion (FD-CTP) can be acquired directly in the angio suite. T...

Purpose The Thrombolysis in Ischemic Stroke Patients (TRISP) collaboration was a concerted effort initiated in 2010 with the purpose to address relevant research questions about the effectiveness and safety of intravenous thrombolysis (IVT). The collaboration also aims to prospectively collect data on patients undergoing endovascular treatment (EVT...

A 59-year-old male patient who suffered from a systemically metastasized, large extrascleral uveal melanoma recurrence of the left eye presented with active hemorrhage from the tumor. He had undergone proton beam irradiation for an epithelioid ciliary body melanoma 4 years before presentation and was lost to follow-up. Magnetic resonance angiograph...

Background: The two middle contacts of directional leads (d-leads) for deep brain stimulation are split into three segments, allowing current steering toward desired axial directions. To facilitate programming, their final orientation needs to be reliably determined. However, it is currently unclear whether d-leads rotate after implantation. Our o...

Purpose Tigertriever is a novel operator-adjustable clot retriever designed to enhance the operator's options to control the interaction of retriever and clot. The aim of this study was to assess the feasibility, safety and efficacy of the Tigertriever device system. Methods Prospective multi-center registry study at three comprehensive stroke cen...

Background: Data on endovascular therapy (EVT) in patients with stroke attributable to CeAD is scarce. We performed a systematic review and meta-analysis of all studies comparing EVT to intravenous thrombolysis (IVT) in CeAD-patients and compared EVT to IVT with regard to 3-month outcome and complications. Additionally, we included data of IVT-/EVT...

Introduction: In patients with stroke attributable to cervical artery dissection, we compared endovascular therapy to intravenous thrombolysis regarding three-month outcome, recanalisation and complications. Materials and methods: In a multicentre intravenous thrombolysis/endovascular therapy-register-based cohort study, all consecutive cervical...

Objective: Our aim was to assess the consequences of aneurysmal subarachnoid hemorrhage (aSAH) on sexual pleasure in patients with an otherwise favorable neurological outcome. Methods: Anonymous, standardized questionnaires concerning sexual function, including the International Index of Erectile Function, Female Sexual Function Index, and a sta...

Objective Intravenous thrombolysis and endovascular therapy (IVT/EVT) are evidence‐based treatments for adults with arterial ischemic stroke (AIS). However, randomized controlled trials in pediatric patients are lacking. This study aimed to describe feasibility, safety, and outcome of IVT/EVT in children with AIS. Methods Retrospective study (01/20...

Objective: To evaluate the effectiveness and clinical utility of a metal artifact reduction (MAR) image reconstruction algorithm for the reduction of high-attenuation object (HAO)-related image artifacts. Methods: Images were quantitatively evaluated for image noise (noiseSD and noiserange) and qualitatively for artifact severity, gray-white-mat...

Knowledge about the recovery of oral intake after hemispheric stroke is important to guide therapeutic decisions, including the administration of enteral tube feeding and the choice of the appropriate feeding route. They aimed to determine the localization and connectivity of lesions in impaired recovery versus recovered swallowing after initially...

Bacterial meningitis as well as herpes encephalitis are acute emergencies with high morbidity and lethality. In the acute phase the history and the careful clinical examination is important for further diagnosis. The analysis of the cerebrospinal fl uid is essential for the therapeutic approach. The indication of diagnostic imaging before lumbar pu...

Background and purpose: Acute stroke patients with severely impaired oral intake are at risk of malnutrition and dehydration. Rapid identification of these patients is necessary to establish early enteral tube feeding. Whether specific lesion location predicts early tube dependency was analysed, and the neural correlates of impaired oral intake af...

Background Acute peroneal palsy is frequently caused by compression, trauma and surgery. Risk factors are weight loss, sitting with crossed legs, wrong positioning during surgery and diabetes mellitus. Focal demyelination is more frequent than axonal damage which in turn is related with an inferior prognosis. Rarely, acquired peroneal palsy is caus...

Background Mechanical thrombectomy has been shown to be an effective and safe therapy for patients suffering an acute stroke. However, shortening the time span between onset of symptoms and recanalization has been partly achieved by a technical method known as aspiration thrombectomy. Our aim is to show the effectiveness of a new tool, the ACE 64,...

Background The aim of this study was to assess reperfusion and clinical outcome of treatment with the self-expanding retrievable Separator 3D in revascularization of acute ischemic stroke. The three-dimensional (3D) device secures thrombus with direct aspiration and supports debulking of the clot. Methods At two centers, 129 consecutive stroke pati...

In selected cases acquired peroneal palsy is caused by intraneural ganglia. In contrast to the much more frequent "loco typico" lesion which is caused by external pressure, intraneural ganglia can be treated by microscopic nerve surgery as part of primary treatment strategy. A careful clinical history as well as a profound clinical and electrophysi...

Von Hippel-Lindau (VHL) disease is an autosomal dominantly inherited tumour predisposition syndrome with an incidence of 1:36,000 newborns, the estimated prevalence in Europe is about 1-9/100,000. It is associated with an increased risk of developing various benign and malignant tumours, thus affecting multiple organs at different time points in th...

Leptomeningeal carcinomatosis is a serious complication of advanced cancer. Various clinical manifestations may present, such as headache, nausea, seizures, cranial neuropathies. In this article, we report the case of a 65-year-old woman with metastatic breast cancer who was admitted to hospital suffering from facial palsy, which was suspected to b...

The aim of this study was to compare the diagnostic accuracy of 3D time-of-flight (TOF-MRA) and contrast-enhanced (CE-MRA) magnetic resonance angiography at 3 T for detection and quantification of proximal high-grade stenosis using multidetector computed tomography angiography (MDCTA) as reference standard. The institutional ethics committee approv...

Eine aneurysmatische Subarachnoidalblutung (aSAB) ist mit hoher Mortalität und Morbidität vergesellschaftet. Nach initia­ ler Stabilisierung des Patienten muss durch neurochirurgische und/oder endovaskuläre Therapieformen die Blutungsquelle ausgeschaltet werden. Aneurysmen, die für beide Therapie­ optionen in Frage kommen, sollten bevorzugt endovas...

To assess the association of lesion location and risk of aspiration and to establish predictors of transient versus extended risk of aspiration after supratentorial ischemic stroke. Atlas-based localization analysis was performed in consecutive patients with MRI-proven first-time acute supratentorial ischemic stroke. Standardized swallowing assessm...

Cerebral cavernomas are thin-walled vascular lesions composed of dilated capillary spaces. De novo formation of cavernomas after cerebral radiotherapy has been suspected since 1994. They are mostly seen in children after irradiation of brain tumours. Radiation dose and the developing juvenile brain are predisposing factors causing cavernomas. Howev...

Background: Cerebral vasospasm is one of the leading causes of poor outcome after aneurysmal subarachnoid hemorrhage. The risk factors for the development of vasospasm have been evaluated in many clinical studies. However, it remains unclear if vasospasm severity can be predicted. The purpose of this study was to determine if different demographic...

Background: Evaluation of various imaging modalities for grading internal carotid artery (ICA) stenosis can be performed by comparison of minimal lumen diameters (MLD) as well as percent ICA-stenosis calculated with a healthy distal reference segment (NASCET method). The two dimensional B-Flow (BF) ultrasound (US) imaging method displays stenoses i...

The optimal treatment for recurrent high-grade gliomas is unknown and a standard of care does not exist. Re-irradiation with concomitant bevacizumab represents an option. Retrospectively, we analyzed a cohort of heavily pretreated patients (n = 14) with relapsing HGGs who underwent re-irradiation with conventional 3D-conformal or intensified modula...

Aortic dissection is the most common and the most lethal event that can involve the aorta. Typically, aortic dissection presents with sharp, tearing, or ripping pain. Alternatively, the patients may suffer from possible extension of the dissecting aneurysm into the supra-aortic vessels resulting in syncope in 9.4 % of patients cerebrovascular accid...

Background and Purpose The tiny size of cerebral aneurysms represents one of the challenging facets for endovascular treatment, with a high risk for intraoperative rupture (IOR). We report on the treatment of tiny ruptured saccular cerebral aneurysms by coil embolization. All cases were that of £ 2–3 mm aneurysms with at least one of the dimensions...

To compare 3D magnetic resonance imaging (3D MRI) with transesophageal echocardiography (TEE) for the detection of complex aortic plaques (≥4 mm thick, ulcerated, or containing mobile thrombi). In all, 99 consecutive patients with acute cryptogenic stroke and ≥3 mm thick aortic plaques in TEE were prospectively included. 3D MRI comprised T1-weighte...

Introduction/Purpose We report on the histopathology results from a preclinical rabbit study and our early clinical experience with the Separator 3D device, featuring novel 3D chambers for securing and removing thrombus. Compatibility with differently sized catheters provides flexibility to combine with aspiration. Materials and Methods To evaluate...

Background: Evaluation of various imaging modalities for grading internal carotid artery (ICA) stenosis can be performed by comparison of minimal lumen diameters (MLD) as well as percent ICA-stenosis calculated with a healthy distal reference segment (NASCET method). The new B-Flow (BF) ultrasound (US) imaging method displays stenosis in a similar...

PURPOSE To compare the diagnostic accuracy of contrast-enhanced MR angiography (CE MRA) and unenhanced 3D time-of-flight MR angiography (3D TOF MRA) in differentiating hemodynamically significant stenosis of the internal carotid artery (ICA) using multidetector CT angiography (CTA) as the reference standard. METHOD AND MATERIALS The institutional...

A 58-year-old female admitted herself to the emergency department with progressive left-sided facial hypoesthesia. Magnetic resonance imaging revealed a 20 mm-sized aneurysm of the left vertebral artery leading to compression of the trigeminal nerve. An endovascular occlusion with a combined coiling and flow-diverter was performed. The left posteri...

Against the background of the increasing dilemma in the scientific community regarding protected versus unprotected carotid artery stent (CAS) placement and the disputed points in interpreting the results of scientific studies as well as the difficulty in conducting such randomized controlled studies, this article gives a review of experiences with...

The aim of this study was to assess the clinical outcome of patients treated with the Penumbra system (PS) for acute ischemic stroke. A retrospective, monocentric matched-pair analysis in comparison with patients treated by intraarterial thrombolysis (IAT) with alteplase was designed for this purpose. Twenty-two consecutive patients, (mean age 62),...

To study the efficacy and safety of a new sclerosing gel of absolute ethanol in the percutaneous treatment of venous malformations (VM). In this prospective, non-randomized multicenter study patients with clinically and by magnetic resonance imaging diagnosed VM were treated. Efficacy and safety of the gel was evaluated. Therapeutic outcome was jud...

The aim of this study was a comparison of the diagnostic value of time-of-flight magnetic resonance angiography (TOF-MRA) and contrast-enhanced (CE) MRA in the setting of acute stroke MRI. The hypothesis was that CE-MRA has at least the same diagnostic value as the commonly used TOF-MRA. A total of 66 stroke patients underwent MRI up to 24 h after...

To investigate the incidence of retrograde flow from complex plaques (> or =4-mm-thick, ulcerated, or superimposed thrombi) of the descending aorta (DAo) and its potential role in embolic stroke. Ninety-four consecutive acute stroke patients with aortic plaques > or =3-mm-thick in transesophageal echocardiography were prospectively included. MRI wa...

To evaluate the contribution of DWI and DTI to the differential diagnosis of cerebral ring enhancing lesions by describing DWI and ADC (apparent diffusion coefficient) findings and measuring the two DTI parameters mean diffusivity (MD) and fractional anisotropy (FA). A total of 17 patients presenting with 26 rim enhancing cysts were investigated wi...

To evaluate patients with wide-necked aneurysms of the posterior circulation who underwent Solitaire AB (ev3, Inc., Irvine, CA) stent-assisted coil embolization. Retrospective analysis of 10 patients (age range, 32-76 years; mean age, 59.1 years) with aneurysms of the basilar artery (basilar tip, n = 5; basilar trunk, n = 4; posterior cerebral arte...

Fragestellung: Ist die 3D MRT der Aorta beim Nachweis komplexer Plaques der Aorta (≥4mm Dicke oder thrombotische Auflagerungen) der transosophagealen Echokardiografie (TEE) uberlegen? Methoden: 99 konsekutive Patienten ≥18 Jahre mit akuter retinaler/zerebraler Ischamie und nachgewiesenen Aortenplaques ≥3mm Dicke in der TEE wurden prospektiv eingesc...

Fragestellung: Sind komplexe Plaques der Aorta descendens (d.h. ≥4mm Dicke oder mit thrombotischen Auflagerungen) eine Emboliequelle fur Schlaganfalle? Methoden: 94 konsekutive Patienten ≥18 Jahre mit akuter retinaler/zerebraler Ischamie und Plaques der Aorta ≥3mm Dicke in der transosophagealen Echokardiografie (TEE) wurden prospektiv eingeschlosse...

Head and neck paragangliomas (HNPs) occur as sporadic or familial entities, the latter mostly in association with germline mutations of the SDHB, SDHC, or SDHD (SDHx) genes. Heritable non-SDHx HNP might occur in von Hippel-Lindau disease (VHL, VHL gene), multiple endocrine neoplasia type 2 (MEN2, RET gene), and neurofibromatosis type 1 (NF1, NF1 ge...

Classification of venous and lymphatic malformations according to the description of the International Society for the Study of Vascular Anomalies is based on clinical and MRI appearance. Although possible limitations exist, it should be carried out for treatment decisions. Treatment modalities include the use of sclerosing agents directly introduc...

Hyperecho-turbo spin-echo (hyperTSE) sequences were developed to reduce the specific absorption rate (SAR), especially at high fields such as 3T and above. The purpose of this study was to quantitatively and qualitatively assess the detection of neuroradiologic pathologies by hyperTSE in comparison with standard turbo spin-echo (TSE180 degrees) seq...

This short review portrays the treatment of cerebral aneurysms from the very early surgical beginning to current endovascular multimodal therapy. The evolution to today’s mainly nonoperative treatment of aneurysms illustrates the enormous progress of interventional neuroradiology, which has attained its outstanding success through the concurrence o...

A recent study showed a dramatic increase in cerebral hemorrhage comprising atypical locations with low-frequency ultrasound-mediated recombinant tissue plasminogen activator-thrombolysis in humans. Here, we provide a possible explanation for this phenomenon by a side effect observed in a study using the similar ultrasound device. The study was ori...

The aim of this study was to assess the regional relative interictal and postictal perfusion changes in temporal and parietal lobe epilepsy. We investigated interictal and postictal magnet resonance perfusion changes in five patients with temporal lobe epilepsy either with hippocampal sclerosis (n = 3) or without (n = 2), and in one patient with ex...

The proximity of thoracic pedicles to the spinal cord and neurovascular structures has prompted numerous efforts to obtain proper screw placement. The aim of this study was to evaluate the feasibility and efficacy of thoracic parapedicular (intercostovertebral) screw fixation by following anatomical landmarks and using fluoroscopy. Thoracic paraped...

Chronic alcohol consumption is frequently accompanied by cerebellar degeneration. The exact aetiology of alcoholic cerebellar degeneration is still a matter of debate. The aim of the present study was to investigate whether patients with chronic alcohol consumption exhibit a decrease in dentate nuclei intensity as measured by MRI, and if so, whethe...

Time-resolved, contrast-enhanced 3D MR angiography combined with parallel imaging at 3T was applied to an intracranial arteriovenous malformation, a dural arteriovenous fistula, and an extracranial facial arteriovenous malformation. The temporal resolution was one image every 1.5 seconds. Arterial feeders were depicted in all three cases. Early ven...

Several case series and a recent meta-analysis indicate that intra-arterial thrombolysis (IAT) is effective for the treatment of acute central retinal artery occlusion (CRAO). A total of 37 patients with acute monocular blindness because of unilateral thromboembolic CRAO were treated with IAT using urokinase within six hours of the onset of symptom...

Increased sarcolemmal permeability has been implicated as a major pathological event in muscular dystrophies. In our study, we evaluated whether damaged muscle fibres can be specifically targeted using albumin as a carrier. We tagged human serum albumin (HSA) with Gadolinium (Gd) and systemically applied this compound (Gd-DTPA-HSA) to wildtype and...

Die zerebrovaskuläre Reservekapazität bezeichnet die Fähigkeit des Gehirns, auf bestimmte Stimuli, wie etwa eine Hyperkapnie oder die Applikation von Acetazolamid, mit einer Durchblutungssteigerung zu reagieren. Eine Einschränkung der zerebrovaskulären Reservekapazität geht bei Patienten mit stenookklusiven Erkrankungen der A. carotis interna bzw....

The aim of the present study was to investigate age-related changes in iron-deposition in dentate nuclei using iron-induced susceptibility effects in magnetic resonance imaging. MR images from 74 healthy subjects (age range 20-68 years) were obtained using a three-dimensional (3D) T1-weighted fast low angle shot (FLASH) echo sequence. Signal intens...

Ziele: Bestimmung der zerebralen CO2-Reaktivitat bei Patienten mit steno-okklusiven Erkrankungen der A. carotis mittels quantitativer Phasenkontrast-MRA. Korrelation mit dem transkraniellen Doppler-CO2-Test (CO2-TCD). Methode: Elf Patienten mit hochgradigen Stenosen bzw. Verschlussen der ACI oder ACC wurden untersucht. An einem 1.5T MR-System wurde...

Wir untersuchten die inter- und postiktalen Veranderungen der Perfusion bei 6 Patienten mit elektroenzephalographisch gesicherter Temporallappen- (n=5) und Parietallappenepilepsie (n=1). Alle Patienten (3 Frauen, 3 Manner, Alter von 23 bis 47 Jahre) litten an komplex-fokalen Anfallen, zusatzlich sekundar-generalisierten (n=4) oder einfach-fokalen A...

To study whether computed tomography (CT) can measure the water content of early ischemic edema. The authors obtained cranial CT in 5 groups of rats subjected to 1 hour (n = 8), 2 hours (n = 11), 3 hours (n = 13), 4 hours (n = 13), or 6 hours (n = 14) of right middle cerebral artery (MCA) occlusion. Immediately after CT, the authors removed the rat...

After focal status epilepticus, focal alterations of the apparent diffusion coefficient (ADC) have been demonstrated in the epileptogenic zone by using diffusion-weighted magnetic resonance (MR)imaging (DWI). Effects of flumazenil on an epileptogenic focus have been demonstrated by EEG recordings, but not by functional MRI. We hypothesized that dyn...

Diffusion-weighted magnetic resonance imaging (DWI) after focal status epilepticus has demonstrated focal alterations of the apparent diffusion coefficient (ADC) in the epileptogenic zone. We hypothesized that localized dynamic alterations of brain diffusion during the immediate postictal state will be detectable by serial DWI and correlate with th...

The differential role of the cerebellar cortex and nuclei has rarely been addressed in human lesion and functional brain imaging studies. One important reason is the difficulty of defining the localization of the cerebellar nuclei and extent of possible lesions based on CT or MR scans. The present MRI investigation was specifically designed to stud...

Classical eyeblink conditioning is used frequently to study the role of the cerebellum in associative learning. To understand the mechanisms involved in learning, the neural circuits that generate the eyeblink response should be identified. The goal of the present study was to examine cerebellar regions that are likely to control the human eyeblink...