Cerebral perfusion changes in acute subdural hematoma.

INTRODUCTION: Acute subdural hematoma (aSDH) is one of the main causes of high mortality and morbidity in traumatic brain injury. Prognosis is poor due to the rapid volume shift and mass effect. Cerebral perfusion is likely affected in this condition. This study quantifies perfusion changes in aSDH using early ER polytrauma CT with perfusion imaging (CTP). METHODS: Data of 54 patients with traumatic aSDH were retrospectively collected. Glasgow Coma scale (GCS), perfusion parameters, therapeutic decisions and imaging data including hematoma thickness, midline shift, and hematoma localization were analyzed. The cortical perfusion parameters of each hemisphere, the area anterior to the hematoma (AAH), area below the hematoma (ABH), area posterior to the hematoma (PAH), and corresponding mirrored contralateral regions were determined. RESULTS: We found a significant difference in Tmax in affected and unaffected whole-hemisphere data (mean 4.0 s vs. 3.3 s, p < 0.05) and a significantly different mean for Tmax in ABH and for the corresponding mirrored area (mABH) (mean 3.8 s vs. 3.1 s, p < 0.05). No significant perfusion changes in cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) were found. CONCLUSION: There was a significant elevation of time to maximum (Tmax) values in the underlying cortical area of aSDH. Possible pathophysiological explanations, the influence on immediate surgical decision-making and further therapeutic consequences have to be evaluated.

MTT Heterogeneity in Perfusion CT Imaging as a Predictor of Outcome after Aneurysmal SAH.

BACKGROUND AND PURPOSE: Impairment of tissue oxygenation caused by inhomogeneous microscopic blood flow distribution, the so-called capillary transit time heterogeneity, is thought to contribute to delayed cerebral ischemia after aneurysmal SAH but has so far not been systematically evaluated in patients. We hypothesized that heterogeneity of the MTT, derived from CTP parameters, would give insight into the clinical course of patients with aneurysmal SAH and may identify patients at risk of poor outcome. MATERIALS AND METHODS: We retrospectively analyzed the heterogeneity of the MTT using the coefficient of variation in CTP scans from 132 patients. A multivariable logistic regression model was used to model the dichotomized mRS outcome. Linear regression was used to eliminate variables with high linear dependence. T tests were used to compare the means of 2 groups. Furthermore, the time of the maximum coefficient of variation for MTT after bleeding was evaluated for correlation with the mRS after 6 months. RESULTS: On average, each patient underwent 5.3 CTP scans during his or her stay. Patients with high coefficient of variation for MTT presented more often with higher modified Fisher (P = .011) and World Federation of Neurosurgical Societies grades (P = .014). A high coefficient of variation for MTT at days 3-21 after aneurysmal SAH correlated significantly with a worse mRS score after 6 months (P = .016). We found no correlation between the time of the maximum coefficient of variation for MTT after bleeding and the patients' outcomes after 6 months (P = .203). CONCLUSIONS: Heterogeneity of MTT in CTP after aneurysmal SAH correlates with the patients' outcomes. Because the findings are in line with the pathophysiologic concept of the capillary transit time heterogeneity, future studies should seek to verify the coefficient of variation for MTT as a potential imaging biomarker for outcome.

R-Type Voltage-Gated Ca²âº Channels in Cardiac and Neuronal Rhythmogenesis.

During the past decades, an increasing number of ion channel and transporter types have been identified acting together to produce cardiac and neuronal pacemaker action potentials. The basis of pacemaker activity was understood in more detail by using single-microelectrode recordings on cells isolated from pacemaker regions. Meanwhile, this powerful technique was complemented by computer modeling and recombinant technologies, including gene inactivation of ion channels and transporters, which may be involved in the generation of the electrical activity of pacemaker cells. Several genes of the voltage-gated Ca(2+) channel (VGCC) family have been ablated, and their role in cardiac and neuronal pacemaking is compared in the present summary, focusing on the role of murine R-type voltage-gated Ca(2+) channels encoded by cacna1e and expressing the ion conducting subunit Cav2.3.

Impact of 5-aminolevulinic acid fluorescence-guided surgery on the extent of resection of meningiomas--with special regard to high-grade tumors.

BACKGROUND AND OBJECTIVES: In high-grade meningiomas and a subgroup of clinically aggressive benign meningiomas tumor control is still insufficient. Recently 5-ALA fluorescence in meningiomas was reported. The impact of 5-ALA fluorescence-guided surgery (FGS) on surgical decision-making and extent of resection has not yet been systematically analyzed, especially not in high-grade meningiomas. The present study deals with three main questions regarding 5-ALA FGS in meningiomas: to assess the potential for discriminating different WHO grades intra-operatively, to analyze the influence on surgical strategy and to evaluate the impact on extent of resection. METHODS: Data from 31 meningiomas operated with 5-ALA FGS were retrospectively analyzed. Intraoperative fluorescence was graded by the surgeon as "no", "low" or "high". Correlations between semi-quantitative fluorescence and histological features (WHO grade) were analyzed. The influence of 5-ALA fluorescence on surgical strategy and the impact of 5-ALA FGS on degree of resection (Simpson grade and post-operative imaging) were studied. In tumors showing infiltrative growth the extent of resection of fluorescence positive tissue was evaluated. RESULTS: The population comprised 19 WHO grade I, 8 grade II and 4 grade III tumors (61% benign and 39% high-grade meningiomas). 94% of the tumors showed positive fluorescence. Different fluorescence intensities were observed: "no" in two, "high" in 12 and "low" in 17 tumors, respectively. A significant correlation between fluorescence intensity and WHO grade was found (ρ=0.557, p=0.001). 5-ALA improved the extent of resection in 3/16 (19%) of grade I and in 6/8 (75%) of grade II/III meningiomas. This improvement was not measurable by the Simpson grading as rated by the surgeon and controlled on post-operative imaging. CONCLUSIONS: In the present population a strong correlation between fluorescence intensity and WHO grade was observed. 5-ALA FGS improved the extent of resection in meningiomas. Especially in high-grade tumors additional information on brain and neurovascular infiltration was provided. The improved resection was not measurable by Simpson's grading necessitating an additional item, which rates residual fluorescence. Long-term studies are necessary to evaluate a possible impact of FGS on recurrence and overall survival.

The impact of brain shift in deep brain stimulation surgery: observation and obviation.

BACKGROUND: The impact of brain shift on deep brain stimulation surgery is considerable. In DBS surgery, brain shift is mainly caused by CSF loss. CSF loss can be estimated by post-surgical intracranial air. Different approaches and techniques exist to minimize CSF loss and hence brain shift. The aim of this survey was to investigate the extent and dynamics of CSF loss during DBS surgery, analyze its impact on final electrode position, and describe a simple and inexpensive method of burr hole closure. METHODS: Sixty-six patients being treated with deep brain stimulation were retrospectively analyzed for this treatise. During surgery, CSF loss was minimized using bone wax as a burr hole closure. Intracranial air volume was calculated based on early post-surgery stereotactic 3D CT and correlated with duration of surgery and electrode deviations derived from post-surgery image fusion. RESULTS: Median early post-surgery intracranial air was 2.1 cm(3) (range 0-35.7 cm(3), SD 8.53 cm(3)). No correlation was found between duration of surgery and CSF-loss (R = 0.078, p = 0.534), indicating that CSF loss mainly occurs early during surgery. Linear regression analysis revealed no significant correlations regarding volume of intracranial air and electrode displacement in any of the three principal axes. No significant difference regarding electrode deviations between first and second side of surgery were observed. CONCLUSIONS: CSF loss mainly occurs during the early phase of DBS surgery. CSF loss during a later phase of surgery can be effectively averted by burr hole closure. Postoperative intracranial air volumes up to 35 cm(3) did not result in significant electrode displacement in our series. Comparing our results to studies previously published on this subject, burr hole closure using bone wax is highly effective.

Traumatic brain injuries in the ancient Egypt: insights from the Edwin Smith Papyrus.

BACKGROUND: Traumatic brain injury (TBI) is probably as old as human beings. The Edwin Smith Papyrus is the first treatise describing the treatment of patients with TBI and allows insights into the medical examination and treatment of head-injured patients in ancient Egypt. METHOD: Clinical, diagnostic, and therapeutic principles in the treatment of TBI in ancient Egypt were analyzed. RESULTS: Methodically, cases and the presentation of each case are neatly classified within the papyrus. The papyrus contains the first description of the brain, pulsations, contusions as the result of TBI, the dura, and cerebrospinal fluid, revealing a more or less sophisticated knowledge of cerebral anatomy. Furthermore, ancient physicians examined wounds, fractures, signs of basal skull fractures, and associated neurological or infectious symptoms, and classified the injury pattern according to their prognosis. Therapeutic options at this time seemed to have been limited. CONCLUSIONS: The Edwin Smith Papyrus reveals astonishing observation skill when considering the methods and limits of ancient times. These physicians were able to recognize many symptoms of TBI and assign them a prognostic value.

Presynaptic 'Ca2.3-containing' E-type Ca channels share dual roles during neurotransmitter release.

Ca2+ influx into excitable cells is a prerequisite for neurotransmitter release and regulated exocytosis. Within the group of ten cloned voltage-gated Ca2+ channels, the Ca(v)2.3-containing E-type Ca2+ channels are involved in various physiological processes, such as neurotransmitter release and exocytosis together with other voltage-gated Ca2+ channels of the Ca(v)1, Ca(v)2 and Ca(v)3 subfamily. However, E-type Ca2+ channels also exhibit several subunit-specific features, most of which still remain poorly understood. Ca(v)2.3-containing R-type channels (here called 'E-type channels') are also located in presynaptic terminals and interact with some synaptic vesicle proteins, the so-called SNARE proteins, although lacking the classical synprint interaction site. E-type channels trigger exocytosis and are also involved in long-term potentiation. Recently, it was shown that the interaction of Ca(v)2.3 with the EF-hand motif containing protein EFHC1 is involved in the aetiology and pathogenesis of juvenile myoclonic epilepsy.