Dual-Layer Detector Cone-Beam CT Angiography for Stroke Assessment: First-in-Human Results (the Next Generation X-ray Imaging System Trial).

BACKGROUND AND PURPOSE: In patients with stroke, IV cone-beam CTA in the angiography suite could be an alternative to CTA to shorten the door-to-thrombectomy time. However, image quality in cone-beam CTA is typically limited by artifacts. This study evaluated a prototype dual-layer detector cone-beam CT angiography versus CTA in patients with stroke. MATERIALS AND METHODS: A prospective, single-center trial enrolled consecutive patients with ischemic or hemorrhagic stroke on initial CT. Intracranial arterial segment vessel conspicuity and artifact presence were evaluated on dual-layer cone-beam CTA 70-keV virtual monoenergetic images and CTA. Eleven predetermined vessel segments were matched for every patient. Twelve patients were necessary to show noninferiority to CTA. Noninferiority was determined by the exact binomial test; the 1-sided lower performance boundary was prospectively set to 80% (98.75% CI). RESULTS: Twenty-one patients had matched image sets (mean age, 72 years). After excluding examinations with movement or contrast media injection issues, all readers individually considered dual-layer cone-beam CT angiography noninferior to CTA (CI boundary, 93%, 84%, 80%, respectively) when evaluating arteries relevant in candidates for intracranial thrombectomy. Artifacts were more prevalent compared with CTA. The majority assessment rated each individual segment except M1 as having noninferior conspicuity compared with CTA. CONCLUSIONS: In a single-center stroke setting, dual-layer detector cone-beam CTA virtual monoenergetic images are noninferior to CTA under certain conditions. Notably, the prototype is hampered by a long scan time and is not capable of contrast media bolus tracking. After excluding examinations with such scan issues, readers considered dual-layer detector cone-beam CTA noninferior to CTA, despite more artifacts.

Experiences of positive encounters with healthcare professionals among women on long-term sickness absence due to breast cancer or due to other diagnoses: a nationwide survey.

BACKGROUND: Experiences of encounters with professionals have been shown to influence return to work (RTW) among sickness absentees in general. The aim was to gain knowledge on experiences of encounters with healthcare professionals and the ability to RTW among women on long-term sickness absence (SA) due to breast cancer (BC) compared to among women on long-term SA due to other diagnoses. METHODS: Analyses of questionnaire data about experiences of encounters with healthcare professionals among 6197 women aged 19-65 years and on a SA spell lasting 4-8 months. Of those, 187 were on SA due to BC. Descriptive statistics and adjusted (for age, birth country, educational level, depressive symptoms) logistic regression analyses with 95% confidence intervals (CI) were conducted. RESULTS: About 95% in both groups of women stated that they had experienced positive encounters with healthcare, and a minority, about 20%, had experienced negative encounters. Four specific types of positive encounters had been experienced to a lesser extent by women with BC: "allowed me to take own responsibility" (odds ratio (OR) 0.6; 95% CI 0.4-0.8), "encouraged me to carry through my own solutions" (OR 0.5; 95% CI 0.4-0.7), "made reasonably high demands" (OR 0.6; 95% CI 0.4-0.9), and "sided with me/stood on my side" (OR 0.6; 95% CI 0.4-0.8). Among the women with BC, 46% stated that positive encounters promoted their ability to RTW compared to 56% among the others. CONCLUSION: Most of the women had experienced positive encounters and about half stated that positive encounters promoted their ability to RTW, although a slightly smaller proportion of the women with BC stated that. This study emphasizes that not only medical treatment but also encounters may influence the ability to RTW, something that is of clinical importance.

The Medina Embolic Device: Karolinska experience.

Background The aim of this study was to report our single centre experience with the Medina Embolic Device (MED). Methods We performed a retrospective analysis of prospectively collected data to identify all patients treated with the MED. A total of 14 aneurysms (non-consecutive), in 13 patients, were treated including one ruptured and one partially thrombosed aneurysm. Fundus diameter was ≥5 mm in all cases. We evaluated the angiographic appearances, the clinical status, complications, and the need for adjunctive devices or repeat treatments. Results Aneurysm location was cavernous internal carotid artery (ICA; n = 1), supraclinoid ICA ( n = 1), terminal ICA ( n = 2), anterior communicating artery (AComA; n = 4), A2-3 ( n = 1), M1-2 junction ( n = 1), posterior communicating artery (PComA; n = 1), superior cerebellar artery (SCA; n = 1), and basilar tip ( n = 2). The average aneurysm fundus size was 8.6 mm (range 7-10 mm) and average neck size 3.75 mm (range 1.9-6.9 mm). Immediate angiographic results were modified Raymond-Roy occlusion classification (mRRC) I n = 2, mRRC II n = 1, mRRC IIIa n = 2, mRRC IIIb n = 2, the remaining 7 aneurysms showed complete opacification. At follow-up angiography (mean 5 months) mRRC I n = 5, mRRC II n = 5, mRRC IIIa n = 3, and persistent filling was seen in 1 aneurysm. Overall, four patients had repeat treatment and one is pending further treatment. Of the aneurysms treated with more than one MED, 75% showed complete occlusion at 6-month follow up whereas only one aneurysm treated with a single device showed complete occlusion. Overall, three patients had temporary complications and there were no deaths. Conclusions The MED is an intra-saccular flow-diverting device with satisfactory angiographic results and an acceptable safety profile. Use of a single MED cannot be recommended and further longer term studies are needed prior to widespread clinical use.

First-In-Man Procedural Experience with the Novel EmboTrap® Revascularization Device for the Treatment of Ischemic Stroke-A European Multicenter Series.

PURPOSE: We describe safety and efficacy aspects of mechanical thrombectomy with the novel stent-type clot retrieval device EmboTrap for revascularization of large-artery occlusions in acute ischemic stroke. MATERIALS AND METHODS: A total of 40 patients with acute ischemic stroke due to large-artery occlusion were treated in five European centers. Clinical and procedural data were collected; self-reported angiographic results and neurologic outcome (discharge and 90 days) were assessed in a standardized manner. RESULTS: The median National Institutes of Health Stroke Scale at admittance was 16; no patient was treated after 12 h. Intravenous thrombolysis (IVT) was received by 65 % of patients. The territorial distribution was as follows: 87.5 % in the anterior circulation: 62.5 % middle cerebral artery and 25 % internal carotid artery (ICA) terminus, comprising 20 % tandem occlusions; and 12.5 % in the posterior circulation, all of which were vertebrobasilar. Revascularization of TICI 2b-3 was achieved in 38 of 40 (95 %) treatments. Additional devices were utilized in 11 of 40 (28 %) cases after a mean of 2.6 passes with EmboTrap prior to switching. The mean number of EmboTrap passes needed was 1.8, with a mean procedural time to reperfusion of 54 min. One patient (2.5 %), who had not received IVT, experienced symptomatic intracranial hemorrhage post-interventionally. Procedural complications were encountered in 2 of 40 cases (5 %); both patients exhibited ICA dissection that was treated conservatively without clinical sequelae. There were no device-related complications. Of 23 available patients, 8 (35 %) had a good outcome after 90 days. CONCLUSION: The procedural results from these five centers suggest that EmboTrap is technically safe. Successful recanalization rates can be expected to be within the range of other stent retrievers.

Economic and environmental optimization of waste treatment.

This article presents the new systems engineering optimization model, OptiWaste, which incorporates a life cycle assessment (LCA) methodology and captures important characteristics of waste management systems. As part of the optimization, the model identifies the most attractive waste management options. The model renders it possible to apply different optimization objectives such as minimizing costs or greenhouse gas emissions or to prioritize several objectives given different weights. A simple illustrative case is analysed, covering alternative treatments of one tonne of residual household waste: incineration of the full amount or sorting out organic waste for biogas production for either combined heat and power generation or as fuel in vehicles. The case study illustrates that the optimal solution depends on the objective and assumptions regarding the background system--illustrated with different assumptions regarding displaced electricity production. The article shows that it is feasible to combine LCA methodology with optimization. Furthermore, it highlights the need for including the integrated waste and energy system into the model.

Challenges when performing economic optimization of waste treatment: a review.

Strategic and operational decisions in waste management, in particular with respect to investments in new treatment facilities, are needed due to a number of factors, including continuously increasing amounts of waste, political demands for efficient utilization of waste resources, and the decommissioning of existing waste treatment facilities. Optimization models can assist in ensuring that these investment strategies are economically feasible. Various economic optimization models for waste treatment have been developed which focus on different parameters. Models focusing on transport are one example, but models focusing on energy production have also been developed, as well as models which take into account a plant's economies of scale, environmental impact, material recovery and social costs. Finally, models combining different criteria for the selection of waste treatment methods in multi-criteria analysis have been developed. A thorough updated review of the existing models is presented, and the main challenges and crucial parameters that need to be taken into account when assessing the economic performance of waste treatment alternatives are identified. The review article will assist both policy-makers and model-developers involved in assessing the economic performance of waste treatment alternatives.

Negative CT angiography findings in patients with spontaneous subarachnoid hemorrhage: When is digital subtraction angiography still needed?

BACKGROUND AND PURPOSE: CTA is becoming the frontline modality to reveal aneurysms in patients with SAH. However, in about 20% of SAH patients no aneurysm is found. In these cases, intra-arterial DSA is still performed. Our aim was to evaluate whether negative findings on CTA can reliably exclude aneurysms in patients with acute SAH. MATERIALS AND METHODS: We conducted a retrospective analysis of all negative findings on CTAs performed from 2005 to 2009 in patients with spontaneous SAH. Findings were compared with DSA. CTAs were performed with a 64-section multidetector row CT scanner. RESULTS: One hundred ninety-three patients with SAH and negative findings on CTA who underwent subsequent DSA were identified. The distribution of blood on unenhanced CT was the following: PMH in 93 patients, diffuse aneurysmal pattern in 50, no blood on CT (xanthochromic LP) in 32, and peripheral sulcal distribution in 18. All patients with PMH had negative findings on DSA. One patient with no blood on CT had vasculitis on DSA. Six of 18 (33%) patients with peripheral blood had vasculitis on DSA. Three of these were also diagnosed by CTA. All except 1 patient with diffuse aneurysmal blood had negative findings on DSA. One patient was diagnosed with an aneurysm on DSA (1/50, 0.5%). Repeat delayed DSA performed in 28 of these patients revealed a small aneurysm in 4 (14%). Five patients had a complication of DSA (2.6%); 1 was a clinical stroke (0.5%). CONCLUSIONS: In patients with SAH, negative CTA findings are reliable in ruling out aneurysms in the PMH pattern or no blood on CT. DSA is indicated in the diffuse aneurysmal pattern of SAH, and repeat delayed DSA is required if the initial DSA findings are negative. When the blood is peripheral, CTA should be scrutinized for vasculitis and DSA is recommended for confirmation.

Vertebrobasilar Dissection with Pseudo-aneurysm or Subarachnoid Hemorrhage: Intracranial Stenting as the Only Treatment. A Report of Three Cases.

SUMMARY: Vertebrobasilar dissection may cause ischaemia or subarachnoid haemorrhage and can pose a significant treatment challenge. Endovascular treatment using stents alone has been described but there are few reports of its clinical application. We here report our experiences from three cases of vertebrobasilar dissection and pseudo-aneurysm or subarachnoid hemorrhage treated with stents alone.

Brain imaging with a flat detector C-arm : Technique and clinical interest of XperCT.

INTRODUCTION: We present the first clinical results from brain tissue imaging with a novel functionality in the angiography room, the XperCT. METHODS: XperCT is a flat detector C-arm volume acquisition functionality integrated with the angiography equipment. We assessed brain images from 42 patients examined with computed tomography (CT) and XperCT. RESULTS: In all patients, XperCT had significantly more beam hardening and reconstruction artifacts than CT, in particular in the posterior fossa. Contrast resolution was better on CT images. Hemorrhage, edema, and ventricular size could be assessed with XperCT in all patients, but CT was superior also in this aspect. In four of the last 12 cases, after the latest software upgrade, it was possible to differentiate between supra-tentorial grey and white substance on XperCT images. CONCLUSION: CT was superior to XperCT regarding brain soft tissue imaging. However, XperCT could in some cases discriminate between grey and white substance. XperCT is a useful new functionality in interventional neuroradiology. In the clinical setting, it improves patient safety by allowing almost instant access to CT-like brain imaging in the angiography room. It can be life saving in situations where complications during an interventional procedure prompt for immediate action.

Neurovascular radiosurgery.

SUMMARY: This article focuses on the treatment of neurovascular diseases, in particular brain arteriovenous malformations (BAVMs), with radiosurgery. The target group for this review is physicians who manage patients with neurovascular diseases, but are not actively engaged in radiosurgery. Radiosurgery for BAVMs is an established treatment with clearly defined risks and benefits. The efficacy of radiosurgery for dural arteriovenous shunts (DAVSs) is probably similar but the treatment has not yet gained the same acceptance. Radiosurgical treatment of cavernomas (cavernous hemangiomas) remains controversial. Well founded predictive models for BAVM radiosurgery show: * The probability of obliteration depends on the dose of radiation given to the periphery of the BAVM. * The risk of adverse radiation effects depends on the total dose of radiation, i.e. the amount of energy imparted into the tissue. The risk is greater in centrally located lesions. The risk of damage to brainstem nucleii and cranial nerves must be added to the risk predicted from current outcome models. * The risk of hemorrhage during the time span before obliteration depends on the BAVM volume, the dose of radiation to the periphery of the lesion and the age of the patient. Central location is a probably also a risk factor.

Subarachnoid Haemorrhage from a Large Cerebral Aneurysm Visible only on Repeat Angiography.

SUMMARY: We report the case of a 49-year-old woman with a massive subarachnoid haemorrhage in conjunction with trauma. The initial cerebral angiography was normal. Three weeks later she had a second subarachnoid haemorrhage. A repeat angiography demonstrated an eight mm aneurysm of the internal carotid artery bifurcation, a region clearly normal in the previous angiography.

Regression of a Flow-Related Ophthalmic Artery Aneurysm After Treatment of a Frontal DAVS. A Case Report.

SUMMARY: We report a case of a frontal dural arteriovenous shunt or fistula (DAVS) adjacent to the left side of the cribriform plate, with bilateral supply from multiple arteries, the most prominent being the dural branches originating from the anterior ethmoidal artery coming from the left ophthalmic artery. Before treatment there was an eight mm flow-related arterial aneurysm proximally on the left ophthalmic artery. After transarterial embolization of the DAVS with N-butyl cyanoacrylate and polyvinyl alcohol, minimal shunting still remained. At follow-up angiography six months after the treatment, the shunt was obliterated and the ophthalmic artery aneurysm had regressed completely. Our case illustrates that complete obliteration of a DAVS may be achieved even though arteriovenous shunting remains at the end of the procedure. Furthermore, a flow-related arterial aneurysm, may not warrant any specific treatment. Elimination of the high flow situation can lead to complete regression of these aneurysms.

Gamma knife outcome models as a reference standard in the embolisation of cerebral arteriovenous malformations.

BACKGROUND: We sought to utilise outcome models from Gamma Knife radiosurgery (GKRS) to cerebral arteriovenous malformations (AVM) as a reference standard in assessing the clinical outcome of embolisation, thus comparing the outcomes of two different management alternatives, in the same patients. METHODS: 87 consecutive patients with 88 AVM were admitted during 1997-1999 for initial embolisation of an AVM. The clinical outcomes were recorded prospectively. Angiography under stereotactic conditions with measurement of AVM volume was performed before and after embolisation. GKRS outcome models were used to predict obliteration rate, complication rate and risk of haemorrhage before and after embolisation. The clinical outcome of embolisation followed by predicted outcome of adjunct GKRS was then compared with the predicted outcome of GKRS as the only treatment. FINDINGS: Eight patients were subjected to microcatheterisation but not to embolisation. By the end of the study period, embolisation had been terminated in 55 patients out of 80 (69%). The predicted outcome of GKRS alone was 58 obliterations and 12 complications while that of the combined management was 58 obliterations and 15 complications. The difference was not significant on the p < 0.1 level. INTERPRETATION: Volume measurement from angiography and outcome models from Gamma Knife radiosurgery are useful as a reference standard in the management of AVM. Absolute volume reduction from embolisation is most prominent for AVM > 10 ml and thus facilitates subsequent radiosurgery. For AVM < or = 10 ml, GKRS as the only treatment can be an alternative to primary embolisation, particularly if no significant volume reduction or obviously beneficial effect of targeted embolisation is expected. Further prospective studies are needed to identify subgroups in which one treatment has advantages over the other.

Cerebral air emboli from angiography in a patient with stroke. A case report.

A 42-year-old woman with subarachnoid and intracerebral hemorrhage was investigated with diagnostic angiography, disclosing an occlusion of the left internal carotid artery and the middle cerebral artery. CT examination immediately after the angiography revealed a 12-h-old infarct of the left middle cerebral artery territory. There was also gas in the arteries supplying the infarcted part of the brain, but not in other vessels. Air had most probably been introduced during the angiography and had consequently been "trapped" in the cortical arteries of the ischemic brain. In the non-ischemic parts of the brain air may have passed through the vessels leaving no trace.

Risk for hemorrhage during the 2-year latency period following gamma knife radiosurgery for arteriovenous malformations.

PURPOSE: Radiosurgery does not immediately obliterate an arteriovenous malformation (AVM), and the risk for hemorrhage still persists until the AVM is occluded. There is controversy about whether this risk is altered after as compared to before radiosurgery. The aim of this paper is to study this topic further and to suggest a model to predict the risk for posttreatment hemorrhage. METHODS AND MATERIALS: The incidence of hemorrhages within the first 24 months following Gamma Knife radiosurgery was studied retrospectively among 1593 AVM patients, and was related to patient, AVM, and treatment parameters. RESULTS: Fifty-six patients experienced a hemorrhage in the latency period, representing an average annual incidence of 1.8%. The incidence of posttreatment hemorrhage was related to the patient's age, AVM volume, minimum dose, and average dose delivered to the AVM nidus. Based on these observations, an equation was defined that could quantify the probability for a posttreatment hemorrhage to occur. CONCLUSION: A model that can predict the probability for a hemorrhage within the first 24 months after radiosurgery is presented. The risk is higher for larger AVMs and for older patients, and it is lower when higher doses of radiation are used.

Volume measurement of cerebral arteriovenous malformations from angiography.

We designed software for measuring the volume of cerebral arteriovenous malformations from angiography and validated it against prescription volumes in radiosurgery. We aimed to create a model for the risk for complications as a function of volume, based on established outcome prediction models for Gamma Knife radiosurgery, but without the need for dose planning. We created an application for computing the volume of cerebral arteriovenous malformations from the intersection of two X-ray cones in stereotactic space. Volume measurements were compared with prescription volumes from dose planning, in phantoms and in patients treated with Gamma Knife radiosurgery for cerebral arteriovenous malformations. Previous studies of 1128 treated patients were used to calculate the risk for complication as a function of the nidus volume. In 63 patients volumes measured with either method correlated, R2 = 0.85. Volume as measured with the intersecting cone model (ICM) correlated with predicted Gamma Knife radiosurgery complication rate, R2 = 0.84. The ICM can thus be used for measurement of AVM volumes less than 10 cm3 from angiography. Outcome models from Gamma Knife radiosurgery may be applied, but with reduced exactness. Standardised AVM volume measurement is valuable for comparing outcome and for quantification of volume reduction after therapy, notably embolisation. Thus the optimal management plan may be selected in conjunction with diagnostic or therapeutic angiography.

Can the probability for obliteration after radiosurgery for arteriovenous malformations be accurately predicted?

PURPOSE: To investigate how accurate different models predict the probability for obliteration following radiosurgery for an arteriovenous malformation (AVM). METHODS AND MATERIALS: The probability for obliteration was calculated for all 838 AVMs with a known treatment outcome and treated at the Karolinska Hospital with Gamma Knife surgery 1970-1993. Four different models were used for the calculation, resulting in four different values of the probability for obliteration. The calculated prediction values were added for each model, and the total number of predicted obliteration compared to that observed in the whole patient material as well as in different subgroups. RESULTS: Three of the four models predicted the total number of obliterations accurately. In two of those three models, the accuracy of the prediction was dependent on AVM volume and treatment dose. In one model only, the prediction was accurate and independent of all investigated parameters. CONCLUSIONS: The probability for obliteration was accurately predicted by one of the models analyzed. In this model, the probability for obliteration was related to the dose to the AVM periphery only. The AVM volume had no independent impact on the probability for obliteration. There was a trend that AVMs with a central location had a better obliteration rate than predicted.