Balloon kyphoplasty and percutaneous vertebroplasty are relatively recent procedures in the treatment of painful vertebral fractures. There are, however, still some uncertainties about the incidence and treatment strategies of pulmonary cement embolisms (PCE). In order to work out a treatment strategy for the management of this complication, we performed a review of the literature. The results show that there is no clear diagnostic or treatment standard for PCE. The literature research revealed that the risk of a pulmonary embolism ranges from 3.5 to 23% for osteoporotic fractures. In cases of asymptomatic patients with peripheral PCE we recommend no treatment besides clinical follow-up; in cases of symptomatic or central embolisms, however, we recommend to proceed according to the guidelines regarding the treatment of thrombotic pulmonary embolisms, which includes initial heparinization and a following 6-month coumarin therapy. In order to avoid any types of embolisms, both procedures should only be performed by experienced surgeons after critical determination of the indications.

Management of pulmonary cement embolism after percutaneous vertebroplasty and kyphoplasty: a systematic review of the literature

The acetazolamide (ACZ) challenge test is a useful clinical tool and a reliable predictor of critically reduced perfusion. In patients with chronic steno-occlusive disease, the ability to maintain normal cerebral blood flow by reducing vascular resistance secondary to autoregulatory vasodilation is compromised. Identification of the presence and degree of autoregulatory vasodilation (reflecting the cerebrovascular reserve) is a significant prognostic factor in patients with chronic cerebrovascular disease. The pharmacologic challenge of a vasodilatory stimulus such as ACZ can also be used to optimize the treatment strategies for these patients. The pathophysiology, methods, and clinical applications of the ACZ challenge test are discussed in this article.

http://www.ajnr.org/content/ajnr/30/5/876.full.pdf

The Acetazolamide Challenge: Techniques and Applications in the Evaluation of Chronic Cerebral Ischemia

Accurate identification of brain function is necessary to understand the neurobiology of cognitive ageing, and thereby promote well-being across the lifespan. A common tool used to investigate neurocognitive ageing is functional magnetic resonance imaging (fMRI). However, although fMRI data are often interpreted in terms of neuronal activity, the blood oxygenation level-dependent (BOLD) signal measured by fMRI includes contributions of both vascular and neuronal factors, which change differentially with age. While some studies investigate vascular ageing factors, the results of these studies are not well known within the field of neurocognitive ageing and therefore vascular confounds in neurocognitive fMRI studies are common. Despite over 10 000 BOLD-fMRI papers on ageing, fewer than 20 have applied techniques to correct for vascular effects. However, neurovascular ageing is not only a confound in fMRI, but an important feature in its own right, to be assessed alongside measures of neuronal ageing. We review current approaches to dissociate neuronal and vascular components of BOLD-fMRI of regional activity and functional connectivity. We highlight emerging evidence that vascular mechanisms in the brain do not simply control blood flow to support the metabolic needs of neurons, but form complex neurovascular interactions that influence neuronal function in health and disease. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.

https://royalsocietypublishing.org/doi/pdf/10.1098/rstb.2019.0631

Separating vascular and neuronal effects of age on fMRI BOLD signals

The consensus conference on intracranial atherosclerosis provides a comprehensive review of the existing literature relevant to the epidemiology, diagnosis, prevention, and treatment of intracranial atherosclerosis, and identifies principles of management and research priorities. Patients who have suffered a stroke or transient ischemic attack attributed to stenosis (50-99%) of a major intracranial artery face a 12 to 14% risk for subsequent stroke during the 2-year period after the initial ischemic event, despite treatment with antithrombotic medications. The annual risk for subsequent stroke may exceed 20% in high-risk groups. In patients with intracranial atherosclerotic disease, short-term and long-term anticoagulation is not superior to antiplatelet treatment. Overall, the subgroup analyses from randomized trials provide evidence about benefit of aggressive atherogenic risk factor management. Intracranial angioplasty with or without stent placement has evolved as a therapeutic option for patients with symptomatic intracranial atherosclerotic disease, particularly those with high-grade stenosis with recurrent ischemic symptoms, medication failure, or both. A multicenter randomized trial is currently under way to compare stent placement with intense medical management for patients with high-grade symptomatic intracranial atherosclerotic disease.

Intracranial atherosclerotic disease: An update

CT head perfusion with IV contrast 5 ☢☢☢ MRI head perfusion with IV contrast 5 O MRI head without IV contrast 5 O MRI head without and with IV contrast 5 O CT head without IV contrast 5 ☢☢☢ CT head with IV contrast 3 ☢☢☢ CT head without and with IV contrast 3 ☢☢☢ MRA head without IV contrast 3 O MRA head without and with IV contrast 3 O CTA head with IV contrast 3 ☢☢☢ Arteriography cervicocerebral 2 ☢☢☢

Cerebrovascular disease: I. The large arteries of the circle of Willis

BACKGROUND AND PURPOSE: Perfusion CT (PCT) has the ability to measure quantitative values and produce maps of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). We assessed cerebral hemodynamics by using these parameters and acetazolamide challenge in patients with cerebrovascular steno-occlusive disease. METHODS: Fifteen patients underwent PCT with acetazolamide challenge. Comparison of mean CBF, CBV, and MTT was determined between hemispheres and before and after acetazolamide challenge. Hemispheric ratio and percent change due to acetazolamide administration were also calculated. Absolute values and percent changes 2 SDs outside the mean from the nonstenotic hemispheres were defined as abnormal. RESULTS: Significant decreases in CBF (−25.1%, P = .003) and significant increases in MTT (47.1%, P CONCLUSION: Parameters obtained from PCT with acetazolamide are promising for the evaluation of cerebral hemodynamics in patients with cerebrovascular steno-occlusive disease.

http://www.ajnr.org/content/ajnr/27/9/1876.full.pdf

Dynamic CT perfusion imaging with acetazolamide challenge for evaluation of patients with unilateral cerebrovascular steno-occlusive disease

BACKGROUND AND PURPOSE: The purpose of this study was to investigate the risk factors for new symptomatic vertebral compression fractures after vertebroplasty at the thoracolumbar junction. MATERIALS AND METHODS: We conducted a retrospective analysis of 53 patients treated with percutaneous vertebroplasty at the thoracolumbar junction (T12, L1). The follow-up period was 15–27 months. The occurrence of new symptomatic vertebral compression fractures was recorded after vertebroplasty. We evaluated patient age and sex, amount of injected cement, vacuum clefts in the collapsed bodies, initial wedge angle of the compression fracture, change of the wedge angle after vertebroplasty, intradiskal cement leak, and percentage of height restoration of the vertebral body. In this report, we surveyed the possible risk factors for new symptomatic vertebral compression fractures. RESULTS: Thirty-nine (74%) of the 53 patients had fluid and/or air in the compression fracture at the thoracolumbar junction (T12, L1). Eight (20.5%) of the 39 patients with vacuum clefts had new symptomatic compression fracture after vertebroplasty between 1 month and 4 days after surgery to 23 months and 4 days after surgery. The patients with new symptomatic compression fracture had higher initial wedge angle and wedge angle change (more than 7°) after vertebroplasty than those without fractures; these data were considered statistically significant. CONCLUSIONS: The incidence of vacuum clefts in the compression fracture at the thoracolumbar junction is high (74%). The severity of initial wedge angle and wedge angle change affects the incidence of new symptomatic compression fracture.

http://www.ajnr.org/content/ajnr/28/6/1042.full.pdf

New symptomatic compression fracture after percutaneous vertebroplasty at the thoracolumbar junction.

Electrochromic (EC) materials have various absorptivity according to their redox states. An electrochromic device (ECD) employing EC material electrodes can change its absorbance toward incident light upon switching external bias. In this study, thin films of polyaniline and tungsten trioxide are electrodeposited on tin-doped indium oxide conducting glass to fabricate EC electrodes. Solid-state ECDs composed of the electrodes and succinonitrile/polyethylene glycol (SN/PEG) composite electrolytes are constructed. Their EC properties, including transmittance modulation ability (ΔT), color-switching response time, coloration efficiency, and color cycling stability, are investigated. The appropriate operating voltage range is scrutinized by a proposed method. The solid-state Pani-WO3 ECD using a SN/PEG composite electrolyte containing 10.0 wt% PEG exhibited the fastest color-switching rate and high ΔT. The device maintained its ΔT for 4500 successive color-switching cycles without significantly decreasing. 

Electrochromic devices composed of polyaniline and tungsten trioxide thin films with succinonitrile/polyethylene glycol solid-state composite electrolyte

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Dynamic CT perfusion imaging with acetazolamide challenge for evaluation of patients with unilateral cerebrovascular steno-occlusive disease

New symptomatic compression fracture after percutaneous vertebroplasty at the thoracolumbar junction.

Electrochromic devices composed of polyaniline and tungsten trioxide thin films with succinonitrile/polyethylene glycol solid-state composite electrolyte