Surpass Flow Diverter for Treatment of Posterior Circulation Aneurysms.

BACKGROUND AND PURPOSE: Flow diverters for the treatment of posterior circulation aneurysms remain controversial. We aimed to identify factors contributing to outcome measures in patients treated with the Surpass flow diverter for aneurysms in this location. MATERIALS AND METHODS: We conducted an observational study of 53 patients who underwent flow-diverter treatment for posterior circulation aneurysms at 15 centers. Key outcome measures were mortality, complete aneurysm occlusion, and modified Rankin Scale score at follow-up. RESULTS: At follow-up (median, 11.3 months; interquartile range, 5.9-12.7 months), 9 patients had died, resulting in an all-cause mortality rate of 17.3% (95% CI, 7%-27.6%); 7 deaths (14%) were directly related to the procedure and none occurred in patients with a baseline mRS score of zero. After adjusting for covariates, a baseline mRS of 3-5 was more significantly (P = .003) associated with a higher hazard ratio for death than a baseline mRS of 0-2 (hazard ratio, 17.11; 95% CI, 2.69-109.02). After adjusting for follow-up duration, a 1-point increase in the baseline mRS was significantly (P < .001) associated with higher values of mRS at follow-up (odds ratio, 2.93; 95% CI, 1.79-4.79). Follow-up angiography in 44 patients (median, 11.3 months; interquartile range, 5.9-12.7 months) showed complete aneurysm occlusion in 29 (66%; 95% CI, 50.1%-79.5%). CONCLUSIONS: Clinical results of flow-diverter treatment of posterior circulation aneurysms depend very much on patient selection. In this study, poorer outcomes were related to the treatment of aneurysms in patients with higher baseline mRS scores. Angiographic results showed a high occlusion rate for this subset of complex aneurysms.

First experiences with a new device for mechanical thrombectomy in acute basilar artery occlusion.

BACKGROUND AND PURPOSE: The aim of this study was to evaluate our first results using a new device for mechanical thrombectomy in patients with acute basilar artery occlusion. METHODS: Between May 2009 and September 2010 a new device for aspiration thrombectomy (The Penumbra System™; Penumbra Inc., Alameda, Calif., USA) was used in 12 patients with acute basilar artery occlusion. We performed a retrospective review of these patients' medical records. RESULTS: One patient received endovascular treatment without intravenous (IV) thrombolysis because of infarction on the initial CT scan. Eleven of 12 patients received IV thrombolysis with rtPA followed by endovascular thrombectomy according to a bridging concept. After thrombolysis, the basilar artery was patent in 1 patient (9%), partially recanalized in 3 (27%) and still occluded in 7 (64%). The endovascular device could not access in 2 patients (17%). Among the remaining 10 patients, the patency rate after thrombectomy was 100%. The overall patency rate after treatment was 9 of 12 (75%) at the time of discharge. National Institute of Health Stroke Scale improved from a median of 27 to a median of 18 after treatment. Four patients died (33%). The survivors had a mean modified Rankin Scale before discharge of 2.3 (range 0-4). CONCLUSIONS: A bridging therapy with the combination of IV thrombolysis with recombinant tissue plasminogen activator and continuous aspiration thrombectomy seems to be a promising therapy strategy for acute basilar artery occlusion. Furthermore, our results confirm the advantage of the additional use of this new thrombectomy device, working with thrombus aspiration, with a satisfactory patency rate and a good clinical outcome.

Endovascular treatment of intracranial arteriovenous malformations with onyx: technical aspects.

BACKGROUND AND PURPOSE: We report our experiences in the treatment of intracranial arteriovenous malformations (AVMs) with Onyx embolization before neuro- or radiosurgery, focusing on the embolization technique with Onyx. METHODS: Ninety-three patients (40 women and 53 men, mean age 38 years) with 94 intracranial AVMs with a mean volume of 9.2 mL were embolized with Onyx. The following features of all AVMs were evaluated before the treatment: type of nidus and shunt, draining veins, and feeding arteries. RESULTS: Complete obliteration rates were 20% at the end of all embolization steps and 53% after embolization and surgery. In 21% of patients the final control angiography is not yet available (after surgery 9%, after radiosurgery 12%). In 4% of patients, radiosurgery was planned due to a persistent arteriovenous shunt. The injection of Onyx resulted in high occlusion rates (volume reduction >90%) when the AVM was in a supratentorial and cortical location, the nidus was compact and plexiform, and when there was a small number of supplying (direct) feeders and one superficial draining vein. Access device-related complications (stuck catheter, vessel perforation) occurred during the embolization of 220 feeding arteries in 6% of patients, with all such instances having had no clinical consequences. CONCLUSION: With knowledge of the morphologic characteristics of AVMs that are suitable for a treatment with Onyx, high occlusion rates and low complication rates in treating a small number of feeders are feasible. Superselective intranidal or perinidal catheter positions and slow, controlled injections that protect the draining veins make the therapy safe even in complex AVMs and critical locations.

Failed visualization of clot signal in cerebral venous thrombosis on initial MR imaging.

Currently, the combination of T1- and T2-weighted spin echo magnetic resonance imaging (MRI) sequences with MR venography is considered the best diagnostic tool for diagnosing cerebral venous thrombosis (CVT), because they allow positive identification of the thrombotic clot along with the disturbed venous flow signal. We report two patients in whom initial MRI with the mentioned techniques did not show a clot signal. In both patients anticoagulation was started despit lacking proof of CVT by imaging and both patients improved. Only on repeated MRI sinus clot signal could be confirmed.

Liponeurocytoma of the left lateral ventricle--case report and review of the literature.

The reported liponeurocytoma of the left lateral ventricle in a 35-year-old man represents the fifth recorded case of a supratentorial intraventricular liponeurocytoma. In this location, liponeurocytomas are very exceptional, whereas it is the typical site for classic central neurocytomas. Conversely, neurocytomas of the cerebellum are predominantly liponeurocytomas with until now more than 25 reported cases. Thus, cerebellar liponeurocytoma is the most frequent neuroepithelial CNS tumor with adipose-like cells followed by ependymomas with a lipid component and supratentorial intraventricular liponeurocytoma. Adipose-like cells in neurocytomas may originate by lipidization of tumor cells, metaplastic transformation of neuroectodermal cells into fat cells or by true adipocytic differentiation. The present case showed also focal glial differentiation with GFAP-positivity of some tumor cells as often seen in cerebellar liponeurocytomas but much rarer in central neurocytomas. Pathogenetic and nosologic implications of supratentorial intraventricular liponeurocytomas are discussed. Future WHO tumor classification should consider that liponeurocytomas are not restricted to the cerebellum. Reports on cerebellar liponeurocytomas with a less favorable clinical course suggest a WHO grade II for liponeurocytomas.

Acute and chronic swine rete arteriovenous malformation models: hemodynamics and vascular remodeling.

BACKGROUND AND PURPOSE: An acute and a chronic arteriovenous malformation (AVM) model were developed by using the swine rete to study hemodynamics and vascular remodeling. The models were also used to study in vivo polymerization kinetics and the distribution of various N-butyl 2-cyanoacrylate (NBCA) and Lipiodol mixtures. METHODS: In the acute swine AVM model, retrograde flow through the left side of the rete was created by the placement of an endovascular shunt through the ipsilateral ascending pharyngeal artery. In the chronic model, flow was redirected retrograde through the left side of rete and ascending pharyngeal artery by creating an arteriovenous fistula between the ipsilateral jugular vein and the common carotid artery. After a period of at least 6 months, the entire head with the rete was connected to a perfusion loop driven by a peristaltic pump. A total of 30 swine were used for both the acute (n = 23) and chronic groups (n = 7). Hemodynamic parameters, including the flow and pressure drop across the rete, were recorded before NBCA embolization. Image processing was used on high-resolution radiographs of the explanted retia to measure the total rete length. Measurements of rete vessel calibers were based on histology. RESULTS: The pressure gradients across retia were higher in the chronic model than in the acute model, but they did not reach the level of statistical significance (23.7 +/- 12.0 mm Hg vs 15.4 +/- 1.4 mm Hg). The rete blood outflow was significantly higher in the chronic model compared with the acute one (139.9 +/- 100.3 mL/min vs 32.5 +/- 17.6; P = .03). The rete length in the chronic model was significantly higher than in the acute model (593.1 +/- 39.9 vs 401.3 +/- 65.2 pixel; P < .001). The average vessel diameter of the rete in the chronic group was 520 microm and 320 microm in the control animals. CONCLUSION: Increased pressure gradients and flow in the chronic swine rete AVM model may be related to increased size and decreased impedance. The resulting hemodynamic changes reflect a true flow-induced vascular remodeling rather than a simple change related to aging and size of the animal.

Acute and chronic swine rete arteriovenous malformation models: effect of ethiodol and glacial acetic acid on penetration, dispersion, and injection force of N-butyl 2-cyanoacrylate.

BACKGROUND AND PURPOSE: Liquid embolic agents are increasingly gaining importance in the embolization of cerebral arteriovenous malformations (AVMs). Currently, the most commonly used agent is N-butyl 2-cyanoacrylate (NBCA). Various NBCA mixtures, arterial hypotension, and Valsalva maneuver (increased positive end-expiratory pressure) during the injection of the acrylate have been used to address hemodynamic and architectural variations of an AVM; however, the precise in vivo polymerization, distribution, and kinetics of NBCA mixtures are unknown. We investigated the effect of different acrylate/Lipiodol mixtures and the addition of glacial acetic acid (GAA) on the penetration, dispersion, and injection force of NBCA. METHODS: A swine rete AVM model that has been described elsewhere was used for the embolization. In one subgroup of animals, embolization was performed immediately after construction of the AVM model. In a second subgroup, a chronic AVM model was used. GAA was added to the NBCA mixture to decrease the pH value of the solution and prolong the polymerization time. The addition of GAA allowed us to reduce the amount of Lipiodol, thereby reducing the viscosity of the mixture. A total of 30 swine were used for both the acute (n = 23) and chronic (n = 7) subgroups. The following mixtures of Lipiodol/NBCA and GAA (% vol/%vol + microL) were used for embolization: 80/20 + 0; 50/50 + 0; 50/50 + 5; 50/50 + 10; and 50/50 + 20. A total of six retia per mixture were used for the analysis. Glue injection pressure profiles were recorded in each experiment. High-resolution radiographic images obtained from the harvested retia were used to correlate the dispersion and depth of glue penetration with the AVM hemodynamics. The effect of different amounts of GAA on the glue dispersion and depth of penetration of the mixtures was also studied. RESULTS: Using the same pressure gradients, less viscous NBCA + GAA mixtures led to a deeper nidal penetration. The addition of 20 microL of GAA resulted in a three times higher penetration and dispersion of the NBCA mixture that was more homogenous. CONCLUSION: The viscosity of the liquid embolic agent used is an important limiting factor for an AVM embolization. Reducing the amount of Lipiodol improves nidus penetration. Quicker polymerization can be overcome by adding GAA, which reduces the pH of the mixture.

Transvenous Treatment of a Dural Arteriovenous Fistula of the Transverse Sinus by Embolization with Platinum Coils and Onyx HD 500+.

SUMMARY: We report the endovascular treatment of a symptomatic dural arteriovenous fistula in a 61- year-old male patient. The medial portion of the fistula was occluded with detachable platinum coils during an initial intervention using a transvenous approach. Due to persistence of the symptoms in a second intervention eight months later the fistula was completely occluded by the transvenous introduction of a liquid embolic agent (Onyx 500+). The liquid embolic agent was introduced under protection by the temporary balloon occlusion of the fistula's venous drainage. After the procedure, the patient was treated for three months with 75 mg clopidogrel (Plavix(R)) and with 100 mg acetylsalicylic acid (ASS(R)). A few days after the intervention, the patient was discharged without any neurological deficit and in good clinical condition. The follow- up examination six months later neither detected a recurrence of the dural arteriovenous fistula in the angiogram nor any neurological symptoms.

Combining MEG and MRI with neuronavigation for treatment of an epileptiform spike focus in the precentral region: a technical case report.

BACKGROUND: Epileptic foci are often located in the vicinity but not necessarily within the boundaries of intra-axial brain tumors. Resection of these tumors is based on two major goals: first, maximizing tumor removal without provoking new neurologic deficits, and second, minimizing epileptic seizure activity. Magnetic source imaging (MSI) depicts the generators of magnetic fields overlaid on individual magnetic resonance (MR) images. Established application areas are lesions located adjacent to or partly within the sensory and motor cortex, or in the depth of the brain, necessitating a surgical approach through functionally highly relevant cortical regions. Magnetoencephalography (MEG) is also applicable for epileptiform spike foci recording during interictal activity. CASE DESCRIPTION: A patient with a recurrent glioma close to the Rolandic cortex scheduled for epilepsy and tumor surgery was investigated with MSI. The MSI data showed an epileptiform spike focus outside the tumor boundaries. The resulting MSI images were integrated into our neuronavigation system. This procedure allowed for the preoperative identification of the sensory and motor cortex, the precise localization of the epileptiform spike focus, and careful planning of the surgical procedure. In this case, we were able to safely resect the recurrent tumor and the epileptiform spike focus under general anesthesia using MSI-based neuronavigational guidance but no conventional intraoperative mapping techniques. CONCLUSION: Magnetic source imaging can be a valuable, noninvasive method for planning and performing tumor resections in high-risk brain regions, especially if an epileptiform spike focus has to be localized and included into the resection strategy.

Combined therapy of cerebral arteriovenous malformations: histological differences between a non-adhesive liquid embolic agent and n-butyl 2-cyanoacrylate (NBCA).

OBJECTIVE: Based on 2 casuistics, the intraoperative qualities of a new, non-adhesive liquid embolic agent (Onyx, Micro Therapeutics. Inc., Irvine, CA, USA) are to be compared to those of n-butyl 2-cyanoacrylate (NBCA) with regard to the histopathological results after preoperative embolization of a cerebral arteriovenous malformation (AVM). PATIENTS AND METHODS: In a case example, the intraoperative quality of the nidus after embolization of a parieto-occipital AVM with Onyx--a new, non-adhesive liquid embolic agent--consisting of ethylene-vinyl alcohol copolymer (EVOH), dimethyl sulfoxide (DMSO) and tantalum, is described. In the second patient, embolization of a frontal high-flow AVM was performed with NBCA. Both patients underwent surgery with complete resection ofthe AVM. RESULTS: From a neurosurgical point of view, Onyx is suitable for preoperative embolization of AVMs, because the nidus intraoperatively remains elastic and formable and can be dissected from the surrounding brain tissue quite well by microsurgical technique. Inflammatory reactions can be found mainly in the lumina of the vessels. CONCLUSIONS: Onyx promises to be an embolic agent well suitable for subsequent neurosurgical resection. Further studies considering various intervals of time between embolization and resection as well as histopathological and electron microscopical examinations are necessary for evaluation of our first experience with this new embolization agent.

Spontaneous occlusion of a cerebral arteriovenous malformation: angiography and MR imaging follow-up and review of the literature.

We present the angiographic and MR imaging course of a 62-year-old man with a right parietal high-flow arteriovenous malformation (AVM), which was diagnosed because of seizures. A spontaneous, complete, and asymptomatic occlusion of the AVM was confirmed by a second angiography 3 months later. The possible mechanisms leading to the occlusion are discussed, and a brief review of the literature is given.

Modification of a previously described arteriovenous malformation model in the swine: endovascular and combined surgical/endovascular construction and hemodynamics.

BACKGROUND AND PURPOSE: The rete mirabile in swine has been proposed as an arteriovenous malformation (AVM) model for acute experimental studies through surgical creation of a large carotid-jugular fistula. This report describes two endovascular modifications to simplify the surgical creation and provides hemodynamic parameters for the AVM model. METHODS: An AVM model was created in 29 animals to study n-butyl 2-cyanoacrylate polymerization kinetics. The common carotid artery (CCA) was punctured and a guiding catheter was inserted tightly into the origin of the ascending pharyngeal artery (APA). The CCA was ligated proximal to the catheter to create a pressure drop across the rete, which represented the AVM nidus. The catheter hub was opened whenever needed and served as the venous drainage of the AVM nidus. The contralateral APA served as the arterial feeder. Instead of the surgical ligation of the CCA, a temporary balloon occlusion was performed in three animals. RESULTS: A mean pressure gradient of 14.9 +/- 10.5 mm Hg (range, 4-42 mm Hg) was measured across the rete. The mean flow rate was 30.4 +/- 14.2 mL/min (range, 3.5-46 mL/min), as measured at the venous drainage. CONCLUSION: The endovascular and combined surgical-endovascular rete AVM model in swine is easy to construct and is less time-consuming than are the currently used models for acute experimental studies. Hemodynamic parameters can be monitored during the entire experiment and correspond to values found in human cerebral AVMs.

Is local intra-arterial fibrinolysis contraindicated in elderly patients with cerebral artery occlusion?

Local intra-arterial fibrinolysis (LIF) is an effective treatment for selected patients in acute thromboembolic occlusion of the middle cerebral artery, vertebrobasilar system or ophthalmic artery. However, the risk/benefit ratio of thrombolysis in patient subgroups requires classification. Advanced age has been regarded as a prognostic factor for poor clinical outcome. We report our experience with LIF in seven patients with a mean age of 79 years (range 76-83 years) who represented thromboembolic occlusion of the basilar, middle cerebral or pericallosal arteries. We discuss why advanced age need not contraindicate LIF.

[Initial nuclear magnetic resonance tomography results of the treatment course of avascular femur head necrosis after femoral core decompression]. / Erste kernspintomographische Ergebnisse des Therapieverlaufs bei avaskulärer Femurkopfnekrose nach Femurkerndekompression.

The vascular femoral head necrosis is a serious illness, especially when appearing in patients aged 30 to 50 years. Many etiologic factors cause a femoral head necrosis such as, for example, high-dose steroids, abuse of alcohol, defect of bone marrow and trauma of the hip. Often the X-ray photograph leads to the diagnosis in the second stage (ARCO 1992) or in the third stage, when the femoral head has begun to collapse. The stage IIc and III shows an evident enhancement in contrast media in MRI. Contrast enhancement is demonstrated by STIR, FATSAT, T1-weighted and dynamic screening sequence. The characteristics of the contrast media enhancement argue for an active concomitant process of destruction and regeneration. This stage has the best chances for a drug or a surgical therapy. The evaluation of the signal intensity by the dynamic screening sequence is considered as an objective contribution for the staging of the femoral head necrosis. This enables one to differentiate between the curable stage IIc and the stage III, showing the beginning of breakdown of the femoral head.

[How certain is teleradiological telediagnosis for the tomographic procedure?]. / Wie sicher ist die teleradiologische Ferndiagnose für Schnittbildverfahren?

PURPOSE: To define the value of teleradiographic studies, a comparison was carried out between digitised copies of CT examinations of the skull with the original images. Differences in image quality obtained from a digital scanner and a camera were quantified. MATERIAL AND METHOD: 56 CT examinations of the skull, 28 of which had discrete abnormalities, were chosen for ROC analysis. The original films were digitised with a Vidar VXR-12 scanner and Panasonic WV-160 and WV-BP 500 cameras. The images were evaluated by five radiologists after image transfer with Video Conference software to a personal computer. RESULTS: For the analysis of the films the area under the ROC curve was 0.91 +/- 0.04, for the digital scanner it was 0.85 +/- 0.04, for camera WV-BP 500 0.89 +/- 0.06 and for camera WE-160 0.87 +/- 0.09. Comparison with the film findings showed. a minimal p-value of 0.17 which indicated that there was no significant reduction in diagnostic value following digitization. CONCLUSION: The probable reason for the slight deterioration using the digital scanner was the reduction to 75 dpi compared with 134 dpi on the CT films. The cameras produce image noise comparable to CT with low window settings and reduced local resolution. We expect similar results for CT with soft tissue windows or for MRT of the skull. Conventional radiographs containing high local resolution, wide grey scale and low image noise would presumably make higher demands on methods of digitization.

Epidural lipomatosis: case report and literature review.

We report a case of symptomatic epidural lipomatosis in a 36-year-old man following a heart lung transplant and 3.5 years of steroid medication. A review of the pertinent literature emphasises the importance of including this diagnosis in the differential diagnosis of patients receiving steroid medication or markedly obese patients with back pain or symptoms suggesting spinal cord or cauda equina compression.

[Lung activity in 201Tl myocardial scintigraphy: distribution and correlation with hemodynamic parameters]. / Die Lungenaktivität in der 201Tl-Myokardszintigraphie: Verteilung und Korrelation zu hämodynamischen Parametern.

UNLABELLED: The aim of this study was 1. to investigate whether the pulmonary activity in 201Tl myocardial scintigraphy can be accurately quantified from the anterior SPECT projection, 2. to determine the pattern of the intrapulmonary Tl distribution, and 3. to assess the influence of parameters of left ventricular function on the lung/heart ratio (LHR). Scintigraphic images of 85 patients were analysed. In 24 patients planar anterior imaging of the thorax was performed in addition to myocardial SPECT, in 41 patients radionuclide ventriculography was performed within 4 weeks after Tl scintigraphy. IN CONCLUSION: 1. pulmonary Tl-content can be quantitated from the anterior SPECT projection with sufficient accuracy, 2. a lower thallium activity was registered over the apical part of the lung as compared to the basal part, and 3. in the multiple regression analysis the left ventricular ejection fraction (LVEF) during exercise and heart rate during exercise (HRex) exhibited the strongest relation to LHR. After correction with regard to HRex the elevated LHR points to a pathological LVEF during exercise.

[123I-iomazenil- and 99mTc-HMPAO in the diagnosis of focal epilepsies: a comparison of untreated and treated patients]. / 123J-Iomazenil- und 99mTc-HMPAO in der Diagnostik fokaler Epilepsien: Vergleich von unbehandelten und behandelten Patienten.

The purpose of this study was to compare HMPAO- and IMZ-SPECT findings in treated and untreated patients with focal epilepsies. We examined 20 patients (untreated 13; treated 7). All patients had a normal CT and/or MRI scan. In all patients both whole-brain activity and regional count density (rcd) were evaluated by SPECT. Furthermore, the specific and non-specific binding of IMZ were calculated for each ROI and the results of both, treated and untreated patients were compared. Our data indicate that the normalized cerebral total binding of IMZ was significantly increased in all regions in the group of treated patients (p < 0.001). In contrast, no difference in the tracer binding was found with HMPAO-SPECT. We conclude that the difference in the IMZ-binding might be due either to exogenous or endogenous factors. In our study IMZ-SPECT had a higher sensitivity and a lower specificity in the detection of decreased rcd in areas with EEG findings that indicate an epileptogenic focus compared with HMPAO-SPECT.