Chronic effects of an aminosteroid on microdialytically measured parameters after experimental middle cerebral artery occlusion in the rat

Emerging imaging tools for use with traumatic brain injury research

This article identifies emerging neuroimaging measures considered by the inter-agency Pediatric Traumatic Brain Injury (TBI) Neuroimaging Workgroup. This article attempts to address some of the potential uses of more advanced forms of imaging in TBI as well as highlight some of the current considerations and unresolved challenges of using them. We summarize emerging elements likely to gain more widespread use in the coming years, because of 1) their utility in diagnosis, prognosis, and understanding the natural course of degeneration or recovery following TBI, and potential for evaluating treatment strategies; 2) the ability of many centers to acquire these data with scanners and equipment that are readily available in existing clinical and research settings; and 3) advances in software that provide more automated, readily available, and cost-effective analysis methods for large scale data image analysis. These include multi-slice CT, volumetric MRI analysis, susceptibility-weighted imaging (SWI), diffusion tensor imaging (DTI), magnetization transfer imaging (MTI), arterial spin tag labeling (ASL), functional MRI (fMRI), including resting state and connectivity MRI, MR spectroscopy (MRS), and hyperpolarization scanning. However, we also include brief introductions to other specialized forms of advanced imaging that currently do require specialized equipment, for example, single photon emission computed tomography (SPECT), positron emission tomography (PET), encephalography (EEG), and magnetoencephalography (MEG)/magnetic source imaging (MSI). Finally, we identify some of the challenges that users of the emerging imaging CDEs may wish to consider, including quality control, performing multi-site and longitudinal imaging studies, and MR scanning in infants and children.

Treatment of dural arteriovenous fistula using ethylene vinyl alcohol (onyx) arterial embolization as the primary modality: short-term results

OBJECT

A dural arteriovenous fistula (DAVF) typically involves meningeal feeding arteries and can cause clinical symptoms ranging from tinnitus to rupture of draining cortical or parenchymal veins. Surgical treatment may be technically demanding. Ethylene vinyl alcohol (Onyx, ev3 Neurovascular) has several properties that make it potentially useful as a primary treatment agent for DAVF. Onyx is expected to be a permanent embolic agent. It should have a decreased risk of catheter retention when compared with other permanent embolic materials.

METHODS

The authors report a series of six patients with symptomatic DAVF who were treated initially with transarterial Onyx embolization and other endovascular techniques.

RESULTS

Five patients had complete occlusion of their DAVF noted on the follow-up angiogram obtained between 2 and 4 months. One patient had residual filling via a small arterial branch that was stable on follow-up angiography. None of the patients had worsening of neurological function. One case was complicated by a retained catheter fragment.

CONCLUSIONS

Transarterial Onyx embolization and other endovascular methods can angiographically obliterate DAVF. In some cases, embolization allowed occlusion of multiple arterial feeding arteries from a single arterial injection. Technically, the embolization was optimized when a microcatheter position immediately adjacent to the point(s) of fistulization was achieved.

Microdialytical monitoring of uric and ascorbic acids in the brains of patients after severe brain injury and during neurovascular surgery

OBJECTIVES

Microdialysis has been extensively used to monitor brain metabolism in the extracellular fluid of patients with severe head injury, to detect the onset of secondary ischaemic damage. The aim was to investigate whether concentrations of uric and ascorbic acids were altered in such patients. Both these compounds play a part in free radical metabolism, which is accelerated after ischaemia and brain injury.

METHODS

Patients with aneurysm or bypass operations were monitored intraoperatively to assess concentrations in minimally disturbed tissue. Afterwards, 13 patients with severe head trauma were monitored for up to 13 days in the intensive care unit.

RESULTS

Intraoperatively, concentrations of both ascorbic and uric acids were significantly higher in the bypass group than in patients with aneurysm, which might be attributed to chronic ischaemic conditions caused by the unilateral occlusion of the carotid artery. In the patients with trauma, mean values of uric acid, varying between 6 microM and 180 microM, did not correlate with type of injury (contusion or diffuse) or duration of monitoring time. Patients who died had significantly higher concentrations of uric acid than those with a good outcome. Ascorbic acid could be detected only intermittently, probably due to technical problems. Concentrations of these two compounds could not be correlated with clinical findings during the course of monitoring.

CONCLUSIONS

Although uric and ascorbic acids are influenced by ischaemic conditions-for example, in bypass patients, neither compound is suitable for monitoring for free radical activity after severe head injury. Patients with a bad outcome tended to have higher concentrations of uric acid.