Increasing the Accuracy of Optic Nerve Measurement Using 3D Volumetry [LETTERS]

REPLY: [LETTERS]

Association of Quantified Location-Specific Blood Volumes with Delayed Cerebral Ischemia after Aneurysmal Subarachnoid Hemorrhage [ADULT BRAIN]

BACKGROUND AND PURPOSE:

Delayed cerebral ischemia is a severe complication of aneurysmal SAH and is associated with a high case morbidity and fatality. The total blood volume and the presence of intraventricular blood on CT after aneurysmal SAH are associated with delayed cerebral ischemia. Whether quantified location-specific (cisternal, intraventricular, parenchymal, and subdural) blood volumes are associated with delayed cerebral ischemia has been infrequently researched. This study aimed to associate quantified location-specific blood volumes with delayed cerebral ischemia.

MATERIALS AND METHODS:

Clinical and radiologic data were collected retrospectively from consecutive patients with aneurysmal SAH with available CT scans within 24 hours after ictus admitted to 2 academic centers between January 2009 and December 2011. Total blood volume was quantified using an automatic hemorrhage-segmentation algorithm. Segmented blood was manually classified as cisternal, intraventricular, intraparenchymal, or subdural. Adjusted ORs with 95% confidence intervals for delayed cerebral ischemia per milliliter of location-specific blood were calculated using multivariable logistic regression analysis.

RESULTS:

We included 282 patients. Per milliliter increase in blood volume, the adjusted OR for delayed cerebral ischemia was 1.02 (95% CI, 1.01–1.04) for cisternal, 1.02 (95% CI, 1.00–1.04) for intraventricular, 0.99 (95% CI, 0.97–1.02) for intraparenchymal, and 0.96 (95% CI, 0.86–1.07) for subdural blood.

CONCLUSIONS:

Our findings suggest that in patients with aneurysmal subarachnoid hemorrhage, the cisternal blood volume has a stronger relation with delayed cerebral ischemia than the blood volumes at other locations in the brain.

Management of Small Unruptured Intracranial Aneurysms: A Survey of Neuroradiologists [INTERVENTIONAL]

BACKGROUND AND PURPOSE:

The long-term history and management of unruptured intracranial aneurysms is not well understood. Our aim was to determine current practice patterns in the management of unruptured intracranial aneurysms, especially regarding imaging surveillance for conservatively managed aneurysms of this type.

MATERIALS AND METHODS:

An on-line survey was designed to examine physician practice and preference regarding the management of small unruptured intracranial aneurysms (≤7 mm in diameter). The survey was circulated to members of the American Society of Neuroradiology. Participation was voluntary, and all responses were anonymous.

RESULTS:

A total of 227 individual survey responses were obtained and included in the analysis with 54.6% (124/227) from diagnostic neuroradiologists (practicing >50% neuroradiology) and one-third (29%) from neurointerventional radiologists. One hundred seventy-three of 227 responded that routine, periodic imaging surveillance would be appropriate for conservatively managed unruptured intracranial aneurysms, and 84% of respondents recommended surveillance frequency of at least once a year. Fifty-nine percent favored indefinite, life-long follow-up for small unruptured intracranial aneurysms, and a similar number of respondents favored noncontrast MR angiography for aneurysm follow-up. Significant heterogeneity was found in size measurements used to assess aneurysms and criteria used to define growth on surveillance imaging.

CONCLUSIONS:

The natural history of intracranial aneurysms is not well-understood. A large proportion of incidentally detected, unruptured aneurysms are small (<7 mm). The survey results show significant heterogeneity in practice even among neuroradiologists and underlies the need to standardize imaging practice. Further studies are needed to assess the optimal frequency and duration of surveillance imaging for unruptured intracranial aneurysms. The criteria used to measure aneurysms and define growth on imaging also need to be standardized.

Surpass Streamline Flow-Diverter Embolization Device for Treatment of Iatrogenic and Traumatic Internal Carotid Artery Injuries [INTERVENTIONAL]

SUMMARY:

Iatrogenic and traumatic cerebral internal carotid artery injuries are uncommon but potentially lethal complications. Direct surgical repair of ICA injuries may be difficult in an acute setting. However, endovascular treatment with a flow-diverter embolization device is a feasible alternative technique that we experienced. In this clinical report, we describe demographic data, radiographic images, lesion characteristics, endovascular procedure notes, postprocedural hospital course, and follow-up digital subtraction angiography of 5 patients. At least 6-month follow-up was available in all patients without occurrence of rebleeding and other complications.

Under Pressure: Comparison of Aspiration Techniques for Endovascular Mechanical Thrombectomy [INTERVENTIONAL]

BACKGROUND AND PURPOSE:

Blood flow should be interrupted during mechanical thrombectomy to prevent embolization of clot fragments. The purpose of our study was to provide a handy overview of the most common aspiration devices and to quantify their flow characteristics.

MATERIALS AND METHODS:

We assessed volumetric flow rates generated by a 60-mL VacLok vacuum pressure syringe, a Pump MAX aspiration pump, and a Dominant Flex suction pump connected to the following: 1) an 8F long sheath, 2) an 8F balloon-guide catheter, 3) an ACE 64 distal aspiration catheter, and 4) an AXS Catalyst 6 Distal Access Catheter. We used a water/glycerol solution, which was kept at a constant temperature of 20°C (viscosity, 3.7 mPa · s).

RESULTS:

Aspiration with the syringe and the Dominant Flex suction pump achieved the highest flows, whereas aspiration with the Pump MAX was significantly lower (P < .001). Resistors in the aspiration system (tubing, connectors, and so forth) restricted flows, especially when the resistance of the catheter was small (due to its large diameter) and the connected resistors became the predominant resistance (P < .001). The syringe achieved an average vacuum pressure of –90 kPa, and the resulting flow was constant during almost the entire procedure of filling the syringe.

CONCLUSIONS:

Sixty-milliliter VacLok vacuum pressure syringes and the Dominant Flex suction pump achieved high and constant flows likely sufficient to reverse blood flow during thrombectomy with an 8F sheath or balloon-guide catheter in the ICA and modern distal aspiration catheters in the MCA. The Pump MAX aspiration pump is dedicated for use with distal aspiration catheters and is unlikely to reverse blood flow in the ICA and MCA without balloon protection.

Treatment of Distal Anterior Cerebral Artery Aneurysms with Flow-Diverter Stents: A Single-Center Experience [INTERVENTIONAL]

BACKGROUND AND PURPOSE:

Flow diversion for aneurysms beyond the circle of Willis is still debated. Our aim was to evaluate the safety and efficacy of flow diversion treatment of distal anterior cerebral artery aneurysms.

MATERIALS AND METHODS:

Consecutive patients with distal anterior cerebral artery aneurysms treated from January 2014 to October 2017 were evaluated retrospectively with prospectively maintained data. Treatment was performed only for unruptured or recanalized aneurysms after coiling. Technical feasibility, procedural complications, aneurysm occlusion (O'Kelly-Marotta grading scale), and clinical outcome were evaluated.

RESULTS:

Fifteen patients were included in the study, with 17 distal anterior cerebral artery saccular aneurysms treated with flow-diverter stents. Mean aneurysm size was 4.25 ± 3.9 mm; range, 2–9 mm. Flow diversion was used as retreatment among 6 previously coiled aneurysms (5 ruptured and coiled in the acute phase, and 1 unruptured and recanalized). Stent deployment was technically successful in all cases. During the perioperative period, 1 patient experienced a transient minor stroke (6%), whereas 2 patients reported acute in-stent thrombosis with disabling ischemic complications (13%). Fourteen patients and 16 aneurysms were available during a mean radiologic follow-up of 12 months (range, 3–24 months). Overall, 12 (75%) aneurysms were completely occluded (O'Kelly-Marotta grading scale score D), 1 aneurysm (6%) showed near-complete occlusion (O'Kelly-Marotta grading scale score C), and 3 aneurysms (19%) were incompletely occluded (O'Kelly-Marotta grading scale, score B). All 6 aneurysms previously coiled were completely occluded after flow diversion, whereas 70% of aneurysms treated with flow diverters alone showed complete/near-complete occlusion (O'Kelly-Marotta grading scale C–D). There were no cases of aneurysm rupture, in-stent occlusion, or retreatment during long-term follow-up.

CONCLUSIONS:

Treatment of distal anterior cerebral artery aneurysms with flow-diverter stents is feasible and effective, with high rates of aneurysm occlusion. Flow diversion plus coiling, in the retreatment of lesions previously coiled, allowed higher rates of occlusion compared with flow diverters alone. However, the risk of ischemic complications is not negligible, and flow-diversion treatment should be evaluated only for aneurysms not amenable to simple coil embolization.

Differentiating Atypical Hemangiomas and Metastatic Vertebral Lesions: The Role of T1-Weighted Dynamic Contrast-Enhanced MRI [SPINE]

BACKGROUND AND PURPOSE:

Vertebral hemangiomas are benign vascular lesions that are almost always incidentally found in the spine. Their classic typical hyperintense appearance on T1- and T2-weighted MR images is diagnostic. Unfortunately, not all hemangiomas have the typical appearance, and they can mimic metastases on routine MR imaging. These are generally referred to as atypical hemangiomas and can result in misdiagnosis and ultimately additional imaging, biopsy, and unnecessary costs. Our objective was to assess the utility of dynamic contrast-enhanced MR imaging perfusion in distinguishing vertebral atypical hemangiomas and malignant vertebral metastases. We hypothesized that permeability and vascular density will be increased in metastases compared with atypical hemangiomas.

MATERIALS AND METHODS:

Consecutive patients from 2011 to 2015 with confirmed diagnoses of atypical hemangiomas and spinal metastases from breast and lung carcinomas with available dynamic contrast-enhanced MR imaging were analyzed. Time-intensity curves were qualitatively compared among the groups. Perfusion parameters, plasma volume, and permeability constant were quantified using an extended Tofts 2-compartment pharmacokinetic model. Statistical significance was tested using the Mann-Whitney U test.

RESULTS:

Qualitative inspection of dynamic contrast-enhanced MR imaging time-intensity curves demonstrated differences in signal intensity and morphology between metastases and atypical hemangiomas. Quantitative analysis of plasma volume and permeability constant perfusion parameters showed significantly higher values in metastatic lesions compared with atypical hemangiomas (P < .001).

CONCLUSIONS:

Our data demonstrate that plasma volume and permeability constant perfusion parameters and qualitative inspection of contrast-enhancement curves can be used to differentiate atypical hemangiomas from vertebral metastatic lesions. This work highlights the benefits of adding perfusion maps to conventional sequences to improve diagnostic accuracy.

Percutaneous CT-Guided Biopsies of the Cervical Spine: Technique, Histopathologic and Microbiologic Yield, and Safety at a Single Academic Institution [SPINE]

BACKGROUND AND PURPOSE:

Cervical spine biopsies can be challenging due to the anatomy and the adjacent critical structures. Percutaneous image-guided biopsies can obviate the need for an open biopsy, however there have been few studies looking at the approaches, safety, and efficacy of percutaneous cervical spine biopsies. This retrospective study evaluated technical considerations, histopathologic and microbiologic yield, and safety in CT-guided cervical bone biopsies.

MATERIALS AND METHODS:

A retrospective review of cervical bone and/or bone/disc biopsies performed from January 2010 to January 2017 was included in this study. Clinical diagnosis and indication, patient demographics, biopsy location, biopsy needle type, technical approach, lesion size, dose-length product, conscious sedation details, complications, and diagnostic histopathologic and/or microbiologic yield were recorded for each case and summarized.

RESULTS:

A total of 73 patients underwent CT-guided cervical bone biopsies. Fifty-three percent (39/73) were for clinical/imaging concern for infection and 47% (34/73) were for primary tumors or metastatic disease. Thirty-four percent (25/73) were of the inferior cervical spine (ie, C6 and C7). A sufficient sample was obtained for histopathologic and microbiologic analyses in 96% (70/73) of the biopsies. Forty-six percent (18/39) of those samples taken for infection had positive cultures. Two intraprocedural complications occurred in which the patients became hypotensive during the procedure without long-term complications.

CONCLUSIONS:

Percutaneous CT-guided biopsy of the cervical spine is an effective and safe procedure with high diagnostic yield and can obviate open procedures for histopathologic and microbiologic analyses of patients with clinical and imaging findings concerning for infection or primary and metastatic osseous lesions.

Anatomic and Angiographic Analyses of Ophthalmic Artery Collaterals in Moyamoya Disease [EXTRACRANIAL VASCULAR]

BACKGROUND AND PURPOSE:

Moyamoya disease is a progressive neurovascular pathology defined by steno-occlusive disease of the distal internal carotid artery and associated with the development of compensatory vascular collaterals. The etiology and exact anatomy of vascular collaterals have not been extensively studied. The aim of this study was to describe the anatomy of collaterals developed between the ophthalmic artery and the anterior cerebral artery in a Moyamoya population.

MATERIALS AND METHODS:

All patients treated for Moyamoya disease from 2004 to 2016 in 4 neurosurgical centers with available cerebral digital subtraction angiography were included. Sixty-three cases were evaluated, and only 38 met the inclusion criteria. Two patients had a unilateral cervical internal carotid occlusion that limited analysis of ophthalmic artery collaterals to one hemisphere. This study is consequently based on the analysis of 74 cerebral hemispheres.

RESULTS:

Thirty-eight patients fulfilled the inclusion criteria. The most frequently encountered anastomosis between the ophthalmic artery and cerebral artery was a branch of the anterior ethmoidal artery (31.1%, 23 hemispheres). In case of proximal stenosis of the anterior cerebral artery, a collateral from the posterior ethmoidal artery could be visualized (16 hemispheres, 21.6%). One case (1.4%) of anastomosis between the lacrimal artery and the middle meningeal artery that permitted the vascularization of a middle cerebral artery territory was also noted.

CONCLUSIONS:

Collaterals from the ophthalmic artery are frequent in Moyamoya disease. Their development depends on the perfusion needs of the anterior cerebral artery territories. Three other systems of compensation could be present (callosal circle, leptomeningeal anastomosis, and duro-pial anastomoses).

Reductive decolorization of azo dyes via in situ generation of green tea extract-iron chelate

Abstract

In this study, rapid decolorization of azo dyes was achieved by in situ-generated green tea extract-iron (GTE-Fe) chelate for the first time. When changing reaction conditions from the aerobic condition to the anaerobic condition, the decolorization efficiencies of two azo dyes, i.e., acid orange 7 (AO7) and acid black 1 (AB1), increased from 46.38 and 83.17 to 90.13 and 95.37%, respectively. The recalcitrant AO7 was then selected as the targeting pollutant in subsequent optimization and mechanism studies. Experimental evidences showed that the initial concentrations of AO7, Fe(III), and GTE are the key factors to optimize the decolorization efficiency. Further characterization studies by spectroscopic analysis, including FESEM, FTIR, and XPS, suggested that the major mechanism of AO7 decolorization is the nucleophilic attack of the oxygen in green tea polyphenols (GTP), and this attack could be facilitated by the organometal chelation. This study provided an efficient and environmental friendly strategy to decolorize azo dyes via in situ generation of the GTE-Fe chelate, as well as its mechanistic insights, shedding lights on in situ remediation of azo dye pollution.

Graphical abstract

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Stochastic convergence of renewable energy consumption in OECD countries: a fractional integration approach

Abstract

In this article, we have examined the hypothesis of convergence of renewable energy consumption in 27 OECD countries. However, instead of relying on classical techniques, which are based on the dichotomy between stationarity I(0) and nonstationarity I(1), we consider a more flexible approach based on fractional integration. We employ both parametric and semiparametric techniques. Using parametric methods, evidence of convergence is found in the cases of Mexico, Switzerland and Sweden along with the USA, Portugal, the Czech Republic, South Korea and Spain, and employing semiparametric approaches, we found evidence of convergence in all these eight countries along with Australia, France, Japan, Greece, Italy and Poland. For the remaining 13 countries, even though the orders of integration of the series are smaller than one in all cases except Germany, the confidence intervals are so wide that we cannot reject the hypothesis of unit roots thus not finding support for the hypothesis of convergence.

Anesthesia for collagenase clostridium histolyticum injection in patients with dupuytren disease: A cohort analysis.

Procedural pain is one of the most common adverse effects reported by patients with Dupuytren disease treated with collagenase clostridium histolyticum (CCH). The aim of this study was to assess the effectiveness of wrist block prior to CCH injection in reducing procedural pain and analyze its impact on adverse effects. We performed a prospective, single-centre study in which we compared two groups of patients in a consecutive cohort. In the first group (NO-BLOCK), wrist block was only performed before finger extension, while in the second group (BLOCK) it was performed before CCH injection and finger extension.

Nicorandil reduces burn wound progression by enhancing skin blood flow

We assessed whether nicorandil, an adenosine triphosphate-sensitive K+ channel opener, reduces burn wound progression in a rat comb burn model. A total of 24 rats were used. Following thermal injury, one dose of nicorandil (10 or 30 mg/kg) was administered intragastrically twice-daily for 3 days. At days 1 and 3 after injury, skin was harvested for histopathologic examination and protein isolation. Rats treated with the 10 mg/kg and 30 mg/kg doses of nicorandil exhibited significantly increased tissue survival in the zone of stasis at days 1 and 3 after injury.

Evolution of an evidence based supermicrosurgery simulation training curriculum: a systematic review

BackgroundSupermicrosurgery (SM) involves operating on vessels with calibers from 0.3-0.8 millimeters. Supermicrosurgery requires skills beyond those of conventional microsurgery. Current microsurgery courses do not prepare a junior surgeon for such a challenge. Several models have been developed to assist in the early learning curve, but their true purpose, benefit and validation have not been addressed. This systematic literature review summarizes the existing SM simulation models, and their likely impact on microsurgery training for small-caliber vessel-based procedures is assessed.

Flap choice does not affect complication rates or functional outcomes following extremity soft tissue sarcoma reconstruction

Flap reconstruction plays an essential role in facilitating limb preservation in patients with extremity soft tissue sarcoma (ESTS). However, the effect of flap choice on the rates of post-operative complications and functional outcomes has not been clearly established. This study directly compares the outcomes of free and pedicled flap reconstructions in ESTS patients.

Treatment of dopplerable nummular headache with minimally invasive arterectomy under local anesthesia

The objective of the current study is to elucidate the potential role of surgery in the treatment of nummular headache.

The ecological competition and grazing reverse the effects of sulfamethoxazole on plankton: a case study on characterizing community-level effect

Abstract

The toxic effects of sulfamethoxazole (SMX) on densities of two algae, Platymonas helgolandica var. tsingtaoensis, Isochrysis galbana, and of a rotifer, Brachionus plicatilis, were tested by the population and community experiments. Two endpoints, the carrying capacity and the densities array of community in steady state (DACS), were used to characterize the toxic effects at a population level and a community one, respectively. The results showed that the carrying capacity of P. helgolandica var. tsingtaoensis and B. plicatilis did not decline significantly in population test when the concentration of SMX was lower than 6.0 mg L⁻¹ and 12.0 mg L⁻¹, respectively. However, I. galbana was sensitive to SMX and had presented toxic effect at 3.0 mg L⁻¹. By extrapolation of toxic effect at a population level to a community one, a derived community-NOEC was 3.0 mg L⁻¹, representing an inference from data of toxic effects at population level. In community experiment, when the customized community was in steady state, the density of I. galbana increased as a whole with SMX concentration in the range of tested concentration (0–144 mg L⁻¹), while that of P. helgolandica var. tsingtaoensis assumed the trend of a reversed "v" in this range. Only the density of B. plicatilis decreased with SMX concentration. With the DACS as endpoint, a NOEC for the customized community was determined to be 6.0 mg L⁻¹. This indicates that interspecific interactions can reverse the toxic effects of SMX on phytoplankton. The DACS was reliable and stable, serving as the endpoints in assessment of the effects of the pollutants on the ecosystems.

Erratum

Why Philosophers should do Semantics (and a bit of syntax too): a Reply to Cappelen

Abstract

In this paper, I address a series of arguments recently put forward by Cappelen Review of Philosophy and Psychology 8(4): 743–762 (2017) to the effect that philosophers should not do formal semantics or be concerned with the "minutiae of natural language semantics". He offers two paths for accessing his ideas. I argue that his arguments fail in favour of the first and cast some doubt on the second in so doing. I then proffer an alternative conception of why exactly philosophers should continue to do formal linguistics which includes both semantics and syntax.