Arteriovenous cerebral blood flow correlation in moderate-to-severe traumatic brain injury: CT perfusion study.

Introduction: The relationship between arterial and venous blood flow in moderate-to-severe traumatic brain injury (TBI) is poorly understood. The research question: was to compare differences in perfusion computed tomography (PCT)-derived arterial and venous cerebral blood flow (CBF) in moderate-to-severe TBI as an indication of changes in cerebral venous outflow patterns referenced to arterial inflow. Material and methods: Moderate-to-severe TBI patients (women 53; men 74) underwent PCT and were stratified into 3 groups: I (moderate TBI), II (diffuse severe TBI without surgery), and III (severe TBI after the surgery). Arterial and venous CBF were measured by PCT in both the internal carotid arteries (CBFica) and the confluence of upper sagittal, transverse, and straight sinuses (CBFcs). Results: In group I, CBFica on the left and right sides were significantly correlated with each other (p < 0.0001) and with CBFcs (p = 0.048). In group II, CBFica on the left and right sides were also correlated (P < 0.0000001) but not with CBFcs. Intracranial pressure reactivity (PRx) and CBFcs were correlated (p = 0.00014). In group III, CBFica on the side of the removed hematoma was not significantly different from the opposite CBFica (P = 0.680) and was not correlated with CBFcs. Discussion and conclusion: The increasing severity of TBI is accompanied by a rising uncoupling between the arterial and venous CBF in the supratentorial vessels suggesting a shifting of cerebral venous outflow.

Cerebral Microcirculation and Oxygenation Modulation by Transcranial Alternating Current Stimulation in Awake and Anesthetized Mice.

Transcranial alternating current stimulation (tACS) is a novel non-invasive electrical stimulation technique where a sinusoidal oscillating low-voltage electric current is applied to the brain. TACS is being actively investigated in practice for cognition and behavior modulation and for treating brain disorders. However, the physiological mechanisms of tACS are underinvestigated and poorly understood. Previously, we have shown that transcranial direct current stimulation (tDCS) facilitates cerebral microcirculation and oxygen supply in a mouse brain through nitric oxide-dependent vasodilatation of arterioles. Considering that the effects of tACS and tDCS might be both similar and dissimilar, we tested the effects of tACS on regional cerebral blood flow and oxygen saturation in anesthetized and awake mice using laser speckle contrast imaging and multispectral intrinsic optical signal imaging. The anesthetized mice were imaged under isoflurane anesthesia ∼1.0% in 30% O2 and 70% N2O. The awake mice were pre-trained on the rotating ball for awake imaging. Baseline imaging with further tACS was followed by post-stimulation imaging for ~3 h. Differences between groups were determined using a two-way ANOVA analysis for multiple comparisons and post hoc testing using the Mann-Whitney U test. TACS increased cerebral blood flow and oxygen saturation. In awake mice, rCBF and oxygen saturation responses were more robust and prolonged as opposed to anesthetized, where the response was weaker and shorter with overshoot. The significant difference between anesthetized and awake mice emphasizes the importance of the experiments on the latter as anesthesia is not typical for human stimulation and significantly alters the results.

Changes of Arterial and Venous Cerebral Blood Flow Correlation in Moderate-to-Severe Traumatic Brain Injury: A CT Perfusion Study.

We compared differences in perfusion computed tomography (PCT)-derived arterial and venous cerebral blood flow (CBF) in moderate-to-severe traumatic brain injury (TBI) as an indication of changes in cerebral venous outflow patterns referenced to arterial inflow. Moderate-to-severe TBI patients (women 53; men 74) underwent PCT and were stratified into 3 groups: I (moderate TBI), II (diffuse severe TBI without surgery), and III (diffuse severe TBI after the surgery). Arterial and venous CBF was measured by PCT in both the middle cerebral arteries (CBFmca) and the upper sagittal sinus (CBFuss). In group I, CBFmca on the left and right sides were significantly correlated with each other (p < 0.0001) and with CBFuss (p = 0.048). In group II, CBFmca on the left and right sides were also correlated (p < 0.0000001) but not with CBFuss. Intracranial pressure reactivity (PRx) and CBFuss were correlated (p = 0.00014). In group III, CBFmca on the side of the removed hematoma was not significantly different from the opposite CBFmca (p = 0.680) and was not correlated with CBFuss. Conclusions: The increasing severity of TBI is accompanied by an impairment of the correlation between the arterial and venous CBF in the supratentorial vessels suggesting shifting in arterial and venous CBF in severe TBI associated with increased ICP reflected by PRx.

Cerebral Net Water Uptake in Posttraumatic Cerebral Ischemia.

We assessed net water uptake changes (NWU) in regions of posttraumatic ischemia in relation to cerebral microcirculation mean transit time (MTT) at moderate-to-severe traumatic brain injury (TBI). MATERIALS AND METHODS: 128 moderate-to-severe traumatic brain injury patients (44 women, 84 men, age: 37 ± 12 years) were stratified into 3 groups: Marshall 2-3: 48 patients, Marshall 4: 44 patients, Marshall 5: 36 patients. The groups were matched by sex and age. Patients received multiphase perfusion computed tomography (PCT) 1-5 days after admission. Net water uptake was calculated from non-contrast computed tomography. Data are shown as a median [interquartile range]. P < 0.05 was considered statistically significant. RESULTS: Cerebral blood flow in posttraumatic ischemia foci in Marshall 4 group was significantly higher than that in the Marshall 5 group (p = 0.027). Net water uptake in posttraumatic ischemia zones was significantly higher than in zones without posttraumatic ischemia (8.1% versus 4.2%, p < 0.001). Mean transit time in posttraumatic ischemia zones was inversely and significantly correlated with higher net water uptake (R2 = 0,089, p < 0.01). CONCLUSIONS: Delay of blood flow through the cerebral microvascular bed was significantly correlated with the increased net water uptake in posttraumatic ischemia foci. Marshall's classification did not predict the progression of posttraumatic ischemia.

Sex-Specific and Dose-Dependent Effects of Drag-Reducing Polymers on Microcirculation and Tissue Oxygenation in Rats After Traumatic Brain Injury.

Traumatic brain injury (TBI) ultimately leads to a reduction in the cerebral metabolic rate for oxygen due to ischemia. Previously, we showed that 2 ppm i.v. of drag-reducing polymers (DRP) improve hemodynamic and oxygen delivery to tissue in a rat model of mild-to-moderate TBI. Here we evaluated sex-specific and dose-dependent effects of DRP on microvascular CBF (mvCBF) and tissue oxygenation in rats after moderate TBI. In vivo two-photon laser scanning microscopy over the rat parietal cortex was used to monitor the effects of DRP on microvascular perfusion, tissue oxygenation, and blood-brain barrier (BBB) permeability. Lateral fluid-percussion TBI (1.5 ATA, 100 ms) was induced after baseline imaging and followed by 4 h of monitoring. DRP was injected at 1, 2, or 4 ppm within 30 min after TBI. Differences between groups were determined using a two-way ANOVA analysis for multiple comparisons and post hoc testing using the Mann-Whitney U test. Moderate TBI progressively decreased mvCBF, leading to tissue hypoxia and BBB degradation in the pericontusion zone (p < 0.05). The i.v. injection of DRP increased near-wall flow velocity and flow rate in arterioles, leading to an increase in the number of erythrocytes entering capillaries, enhancing capillary perfusion and tissue oxygenation while protecting BBB in a dose-dependent manner without significant difference between males and females (p < 0.01). TBI resulted in an increase in intracranial pressure (20.1 ± 3.2 mmHg, p < 0.05), microcirculatory redistribution to non-nutritive microvascular shunt flow, and stagnation of capillary flow, all of which were dose-dependently mitigated by DRP. DRP at 4 ppm was most effective, with a non-significant trend to better outcomes in female rats.

Moderate Severity SARS-CoV-2 (COVID-19) Affects Ocular Vergence Indices: Eye Tracking-Based Study.

OBJECTIVE: Since the start of the SARS-CoV-2 (COVID-19) pandemic, it has become clear that the brain is one of the main targets for acute and chronic damage. Although neurodegenerative changes have yet to be investigated, there is already a large body of data on damage to its fiber tracts. A mobile eye tracker is possibly one of the best tools to study such damage in a COVID hospital setting. At the same time, the available data indicate that eye tracking parameters, even in healthy volunteers, demonstrate a distinct gender-specific difference.The aim of the work is to evaluate functional and structural impairments of the fiber tracts and to find possible gender-specific dynamics of eye tracking indicators in the acute period of COVID-19 pneumonia (Delta variant) of moderate severity. MATERIALS AND METHODS: A single-center non-randomized retrospective study included 84 patients in the acute period of moderate severity SARS-CoV-2 (COVID-19) pneumonia (Delta variant) (Group 1). The mean time from admission was 1.4 ± 1.2 days. M:41, F:43. According to thoracic CT, the lung involvement ranged from CT 1 to CT 2. SpO2 ranged from 95% to 99%. The mean age was 35.5 ± 14.8 years (from 18 to 60). The control group (Group 2) included 158 healthy volunteers without pathology of the vision organs and central nervous system.The eye vergence index (VRx) was determined using eye tracking as a motion correlation coefficient between the angular velocities of the left and right eyeballs and was a measure of the conjugation of horizontal and vertical eye movements.The mobile complex Eye Tracker Low-Speed 20 (BVG LLC, the Netherlands) was used. Eye tracking parameters were assessed by vertical and horizontal eye vergence (VVRx and HVRx).Statistical analysis was done using the methods of parametric and non-parametric statistics. RESULTS: Moderate COVID-19 pneumonia resulted in a significant decrease in both VVRx and HVRx compared to controls (0.763 ± 0.127 and 0.856 ± 0.043; p < 0.000001; 0.729 ± 0.018 and 0.776 ± 0.023 p < 0.000001, respectively). VVRx values were significantly higher in men (0.775 ± 0.046 and 0.747 ± 0.091, p = 0.019, respectively), while Ð¥VRx values were significantly higher in women (0.665 ± 0.018 and 0.728 ± 0.024, p < 0.0000001, respectively). CONCLUSIONS: SARS-CoV-2 (COVID-19) of moderate severity is accompanied by a significant deterioration in eye tracking performance proving functional and structural impairments (p < 0.05). VVRx was significantly higher in men, and HVRx was substantially greater in women reflecting gender-specific differences.

Involvement of Endothelial Nitric Oxide Synthase in Cerebral Microcirculation and Oxygenation in Traumatic Brain Injury.

Traumatic brain injury (TBI) leads to cerebral microvascular dysfunction and cerebral ischemia. Endothelial nitric oxide synthase (eNOS) is a key regulator of vascular homeostasis. We aimed to assess the role of eNOS in cerebral blood flow (CBF) changes after TBI. Moderate TBI was induced in eNOS knockout (KO) and wild-type (WT) mice (8 per group). Cerebral microvascular tone, microvascular CBF (mCBF) and tissue oxygenation (NADH) were measured by two-photon laser scanning microscopy (2PLSM) before and 1 h, 1 day and 3 days after TBI. Cerebrovascular reactivity (CVR) was evaluated by the hypercapnia test. Laser Doppler cortical flux (cLDF) was simultaneously measured in the perilesional area. One hr after TBI, cLDF was 59.4 ± 8.2% and 60.3 ± 9.1% from the baseline (p < 0.05) in WT and eNOS KO, respectively. 2PLSM showed decreased arteriolar diameter, the number of functioning capillaries, mCBF and tissue oxygenation (p < 0.05). At 1 day, cLDF increased to 65.2 ± 6.4% in the WT group, while it decreased to 56.1 ± 7.2% in the eNOS KO mice. 2PLSM revealed a further decrease in the number of functioning capillaries, mCBF, and oxygen supply which was slightly milder in WT mice (p < 0.05 from the baseline). On the third day after TBI, cLDF increased to 72 ± 5.2% in the WT, while it stayed the same in the eNOS KO group (55.9 ± 6.4%, p < 0.05 from the WT). 2PLSM showed reduction in arterioles with vasospasm, increase in the number of functioning capillaries, and improvement in mCBF and tissue oxygen supply in WT, while no significant changes were observed in eNOS KO (p < 0.05). CVR was impaired in both groups 1 h after TBI, and improved by the third day in the WT, while staying impaired in eNOS KO. In the subacute TBI period, the significance of eNOS in maintaining cerebral microcirculation and oxygen supply increases with time after the injury.

NIRS-Based Study of Local Cerebral Oxygenation During Transcranial Direct Current Stimulation in Patients with Mild Traumatic Brain Injury.

The purpose of our study was to assess the dynamics of local cerebral oxygenation (LCO) by near-infrared spectroscopy (NIRS) during transcranial direct current stimulation (tDCS) in the acute stage of mild traumatic brain injury (mTBI). Fifty-seven mTBI patients (18 women and 39 men, 35 ± 11.7 years old, GCS 13.7 ± 0.7) were treated by tDCS at 3-5 days after head injury. Stimulation parameters were: 1 mA, 9 V, duration-20 min. A cerebral oximeter was used to assess LCO-values in the frontotemporal lobes. Anodal and cathodal LCO values were compared before tDCS and every 2 min until the tDCS end. Significance was preset to p < 0.05. Results: A significant decrease in LCO values on the anodal side was observed at the 8th to 12th minutes of stimulation, compared to the cathodal side (at 8th minute - p = 0.011; at 12th minute - p < 0.00000001) and compared to LCO values before tDCS (p < 0.00001). The LCO on the cathodal side was not significantly different during the whole tDCS. At the end of the procedure, the interhemispheric LCO differences were not statistically significant (p = 0.757). Conclusions: Transcranial DCS in 3-5 days of mTBI leads to a significant decrease in the LCO value on the anodal side between 8 and 12 min and subsequent recovery to baseline values by the end of the procedure.

Critical Closing Pressure of Cerebral Circulation at Concomitant Moderate-to-Severe Traumatic Brain Injury.

BACKGROUND: Critical closing pressure (CrCP) is the pressure below which local pial blood pressure is inadequate to prevent blood flow cessation. The state of cerebral CrCP in patients with concomitant moderate-to-severe traumatic brain injury (cTBI) after brain lesions surgery remains poorly understood. AIM: The aim of our study was to establish the dynamics of CrCP after intracranial surgery in traumatic brain injury (TBI) patients with polytrauma. MATERIAL AND METHODS: Results of the treatment of 70 patients with moderate-to-severe сTBI were studied (Male: Female - 39:31, mean age -33.2 ± 12.2 years). Depending on intracranial surgery, patients were divided into 2 groups. All patients were subjected to transcranial Doppler of both middle cerebral arteries, and evaluation of mean arterial pressure (MAP). Based on the data obtained, CrCPs were calculated. Significance was preset to P < 0.05. RESULTS: Mean CrCP values in each group were significantly higher than a reference range (р < 0.01). There was no significant difference in CrCP values between the left and right hemispheres in the group 1 (p = 0.789). In the group 2, mean CrCP values on the unoperated side remained significantly lower than on the operated side (p = 0.000011) even after intracranial surgery. In group 1, mean CrCP values were significantly lower than on the surgery side in the group 1 (Z = 3,4; р = 0.043). CONCLUSION: CrCP values in concomitant moderate-to-severe TBI after removing brain lesions and without surgery were significantly higher than referral data. Even after removal of brain lesions volumes in patients with concomitant moderate-to-severe TBI, CrCP values on the surgery side remained markedly higher than on the side opposite to the removed lesion volumes.

The Changes in Brain Oxygenation During Transcranial Alternating Current Stimulation as Consequences of Traumatic Brain Injury: A Near-Infrared Spectroscopy Study.

The aim was to evaluate the changes in brain tissue oxygenation, assessed by near-infrared spectroscopy (NIRS), during transcranial alternating current stimulation (tACS) in patients with mild and moderate traumatic brain injury (TBI). Nineteen patients with diffuse, blunt, non-severe TBI (mean age 32.7 ± 11.4 years; 4 women and 15 men; Glasgow Coma Score before tACS 14.1 ± 0.5) were treated by 10 Hz in-phase tACS applied for 30 minutes to the left and right lateral prefrontal cortex at 21 days after TBI. Regional cerebral tissue oxygen saturation (SctO2) in the frontal lobes was measured simultaneously by the cerebral oximeter. Significance was preset to P < 0.05. The SctO2 values before tACS were not different between hemispheres ~65%. After 15 minutes of tACS, a significant (p < 0.05) decrease in regional SctO2 was observed with the minimum at the eighth minute of 53.4 ± 3.2% and 53.4 ± 3.2% in the left and right hemispheres, respectively. At the end of the stimulation (30 minutes), the hemispheric differences in cerebral oxygen saturation became statistically insignificant again (p > 0.05). Therefore, tACS causes a significant decrease in SctO2, probably, due to neuronal activation. Our data indicate that tACS may need to be supplemented with oxygen therapy. Further research is required.

Microcirculatory Biomarkers of Secondary Cerebral Ischemia in Traumatic Brain Injury.

AIM: The purpose of this study was to study changes in cerebral microcirculation parameters in the development of secondary cerebral ischemia (SCI). METHODS: A total of 202 patients with a Glasgow Coma Scale score ≤ 12 after experiencing a traumatic brain injury (TBI) were recruited for the study within 6 h of the injury. All patients were subjected to perfusion computed tomography. The cerebral blood flow velocity was recorded using transcranial Doppler ultrasound. The arterial blood pressure was measured noninvasively. The cerebrovascular resistance (CVR), cerebral arterial compliance (CAC), cerebrovascular time constant (CTC), and critical closing pressure (CCP) were measured using the neuromonitoring complex. All patients had unilateral foci of posttraumatic ischemia. Statistical analysis was performed using a paired Student's t test and factor analysis. RESULTS AND CONCLUSION: The CVR and CCP were significantly increased in patients who developed SCI after TBI, whereas the CAC and CTC were significantly decreased (P < 0.05). Factor analyses revealed that the CVR, CAC, and CTC were significantly associated with development of posttraumatic ischemia (P < 0.05). The changes in the CVR and CCP in patients with TBI were significantly associated with SCI development (P < 0.05).

Assessment of Cerebral Autoregulation in the Perifocal Zone of a Chronic Subdural Hematoma.

INTRODUCTION: The knowledge of conservative treatment modalities for a chronic subdural hematoma (CSDH) is still based on low-grade evidence. The purpose of this study was to evaluate the condition of the microcirculation and autoregulation in the perifocal CSDH zone for understanding of the mechanism of CSDH development. METHODS: Cerebral microcirculation was evaluated in patients with the aid of brain perfusion computed tomography (PCT) within the first day. Perfusion parameters were assessed quantitatively in the cortex zone adjacent to the CSDH and in a similar zone of the contralateral hemisphere. The same PCT data were assessed quantitatively without and with use of a perfusion calculation mode excluding large-vessel voxels ("remote vessels" (RVs)) in the first and second methods, respectively. RESULTS: The first method of analysis of a similar zone in the contralateral hemisphere revealed significant increases in cerebral blood volume and cerebral blood flow (P < 0.01) in comparison with normal values. Use of the second method with RVs showed no significant changes in perfusion parameters in microcirculatory blood flow in the cortex on the side contralateral to the hematoma. CONCLUSION: The persistence of microcirculatory blood flow perfusion reflects preservation of cerebral blood flow autoregulation in patients with a CSDH.

Secondary Cerebral Ischemia at Traumatic Brain Injury Is More Closely Related to Cerebrovascular Reactivity Impairment than to Intracranial Hypertension.

The purpose of this study was to investigate the relationship between the development of secondary cerebral ischemia (SCI), intracranial pressure (ICP) and cerebrovascular reactivity (CVR) after traumatic brain injury (TBI). METHODS: 89 patients with severe TBI with ICP monitoring were studied retrospectively. The mean age was 36.3 ± 4.8 years, 53 men, 36 women. The median Glasgow Coma Score (GCS) was 6.2 ± 0.7. The median Injury Severity Score was 38.2 ± 12.5. To specify the degree of impact of changes in ICP and CVR on the SCI progression in TBI patients, logistic regression was performed. Significant p-values were <0.05. RESULTS: The deterioration of CVR in combination with the severity of ICP has a significant impact on the increase in the prevalence rate of SCI. A logistic regression analysis for a model of SCI dependence on intracranial hypertension and CVR was performed. The results of the analysis showed that CVR was the most significant factor affecting SCI development in TBI. CONCLUSIONS: The development of SCI in severe TBI depends largely on CVR impairment and to a lesser extent on ICP level. Treatment for severe TBI patients with SCI progression should not be aimed solely at intracranial hypertension correction but also at CVR recovery.

Improved Cerebral Perfusion Pressure and Microcirculation by Drag Reducing Polymer-Enforced Resuscitation Fluid After Traumatic Brain Injury and Hemorrhagic Shock.

Hemorrhagic shock (HS) after traumatic brain injury (TBI) reduces cerebral perfusion pressure (CPP) and cerebral blood flow (CBF), increasing hypoxia and doubling mortality. Volume expansion with resuscitation fluids (RFs) for HS does not improve CBF and tissue oxygen, while hypervolemia exacerbates brain edema and elevates intracranial pressure (ICP). We tested whether drag-reducing polymers (DRPs), added to isotonic Hetastarch (HES), would improve CBF but prevent ICP increase. TBI was induced in rats by fluid percussion, followed by controlled hemorrhage to mean arterial pressure (MAP) = 40 mmHg. HES-DRP or HES was infused to MAP = 60 mmHg for 1 h, followed by blood reinfusion to MAP = 70 mmHg. Temperature, MAP, ICP, cortical Doppler flux, blood gases, and electrolytes were monitored. Microvascular CBF, tissue hypoxia, and neuronal necrosis were monitored by two-photon laser scanning microscopy 5 h after TBI/HS. TBI/HS reduced CPP and CBF, causing tissue hypoxia. HES-DRP (1.9 ± 0.8 mL) more than HES (4.5 ± 1.8 mL) improved CBF and tissue oxygenation (p < 0.05). In the HES group, ICP increased to 23 ± 4 mmHg (p < 0.05) but in HES-DRP to 12 ± 2 mmHg. The number of dead neurons, microthrombosis, and the contusion volume in HES-DRP were significantly less than in the HES group (p < 0.05). HES-DRP required a smaller volume, which reduced ICP and brain edema.

NIRS-Based Assessment of Cerebral Oxygenation During High-Definition Anodal Transcranial Direct Current Stimulation in Patients with Posttraumatic Encephalopathy.

The aim was to evaluate the changes in brain tissue oxygenation, assessed by near-infrared spectroscopy (NIRS) during high-definition transcranial direct current stimulation (HD-tDCS) in patients with posttraumatic encephalopathy (PTE). Fifty-two patients with PTE after diffuse, blunt, non-severe traumatic brain injury (TBI) (14 women and 38 men, 31.8 ± 12.5 years, Glasgow Coma Score before tDCS 13.2 ± 0.3) were treated with HD-tDCS at 21 days after TBI. The parameters were as follows: 1 mA, 9 V, and current density ~0.15 mA/cm2. The duration of HD-tDCS was 30 min. The anodal and cathodal electrodes were placed over the left M1 and contralateral supraorbital region, respectively. HD-tDCS was delivered by a direct current stimulator with a pair of surface sponge electrodes (S = 3 cm2). Regional cerebral oxygen saturation (SctO2) in the frontal lobes was measured simultaneously and bilaterally by the cerebral oximeter. SctO2 values were compared before stimulation, by the 15th minute and at the end of the tDCS. Significance was preset to p < 0.05. Results. Before the stimulation, SctO2 values varied between 53% and 86% (74 ± 7.1%) without significant difference between hemispheres (p = 0.135). After 15 min, a significant (p < 0.0000001) decrease in regional SctO2 on the anodal side was observed (mean 54.5 ± 5.6%). On the cathodal side, SctO2 remained unchanged. At the end of the stimulation (30 min), differences between the hemispheres in SctO2 remained statistically significant (p < 0.05). Conclusions. In patients with PTE complicated by TBI, HD-tDCS causes a statistically significant (p < 0.05) decrease in regional SctO2 on the anodal side.

Cerebral Critical Closing Pressure in Concomitant Traumatic Brain Injury and Intracranial Hematomas.

The critical closing pressure (CrCP) is the pressure below which the local pial blood pressure is inadequate to prevent blood flow cessation. The cerebral CrCP in concomitant traumatic brain injury (TBI) and intracranial hematomas (TBI + ICH) remains understudied. The aim was to determine the status of the CrCP at сTBI with and without the ICH development. MATERIAL AND METHODS: The results of the treatment of 90 patients with severe to moderate сTBI were studied (male/female - 49:41). The average age was 34.2 ± 14.4 years. Depending on the presence of ICH, patients were divided into two groups. All patients were subjected to transcranial Doppler of the both middle cerebral arteries, and evaluation of mean arterial pressure (MAP). Based on data obtained, the CrCPs were calculated. Significance was preset to p < 0.05. RESULTS: The mean CrCP values in each group appeared to be significantly higher than a referral value (р < 0.05). The mean CrCP values in the perifocal zone of removed hematoma were significantly higher than in TBI patients without ICH (р = 0.015 and р = 0.048, respectively). Analysis of CrCP values in various types of ICH showed no statistically significant differences (р > 0.05). DISCUSSION: The CrCP significantly differs in the groups of TBI patients with and without ICH. The comparability of the groups in respect to the concomitant injury structure proves that the revealed CrCP changes result from the traumatic compression of the brain.

Comparative Analysis of Simultaneous Transcranial Doppler and Perfusion Computed Tomography for Cerebral Perfusion Evaluation in Patients with Traumatic Brain Injury.

The aim was to investigate the feasibility of simultaneous comparison of cerebral circulation in major vessels and microvasculature in patients suffering traumatic brain injury (TBI) with or without intracranial hematomas (IH). METHODS: 170 patients were divided into two groups: Group 1 - diffuse TBI (75 patients); and Group 2 - TBI with IH (95 patients: 18 epidural, 65 subdural and 12 multiple). Perfusion computed tomography (PCT) for assessment of volumetric cerebral blood flow (CBF) was done 2-15 days after admission to hospital. Simultaneous assessment of cerebral blood flow velocity (CBFV) in both middle cerebral arteries was done by transcranial Doppler. RESULTS: In patients with diffuse TBI, CBF had statistically valid correlations with CBFV (r = 0.28, p = 0.0149 on the left side; r = 0.382, p = 0.00075 on the right side). In patients with TBI and IH, the analysis did not reveal any reliable correlations between the CBFV and CBF velocity in the temporal lobes, either on the side of the removed IH or on the opposite side. CONCLUSION: The greatest linear correlation was noted in patients with diffuse TBI without the development of a coarse shift of the midline structures and dislocation syndrome. This correlation decreases with the increase in injury severity and development of secondary complications in the acute period, which probably reflects impairment of the coupling of oxygen consumption by brain tissue and cerebral microcirculation.

The Treatment of a Ruptured Anterior Communicating Artery (ACoA) Aneurysm with Coiling and Flow Disruptor (WEB-Device) and Management of Symptomatic Post-Interventional Delayed Vasospasm: A Case Report.

The article reports a clinical case illustrating a favorable outcome of endovascular treatment of a patient with a ruptured wide range neck ACoA aneurysm by WEB-Device. The peculiar characteristics of the pre-procedural period and the procedure are described.

Cerebral Arterial Compliance in Polytraumazed Patients with Cerebral Vasospasm.

The purpose was to determine the status of the cerebral arterial compliance (cAC) in a concomitant head injury and cerebral vasospasm (CVS) with and without the development of intracranial hematomas (ICH). In Materials and Methods, we examined 80 polytrauma patients with severe TBI and CVS. During or immediately after dynamic helical computed tomography angiography (DHCTA), the monitoring of the transcranial Doppler of the MCA was recorded bilaterally with 2-MHz probes. The cerebral blood volumes were calculated from the DHCTA data with complex mathematical procedures using the "direct flow model" algorithm. In Results, CAC was significantly decreased (p < 0.001) in both the first and second group TBI and CVS (with or without ICH) in comparison with normal data (p < 0.001) and TBI without CVS. The cAC was significantly decreased on the side of the former hematoma with CVS than on the contralateral side with CVS (р = 0.003). In Conclusion, the cAC in TBI and CVS gets significantly lower as compared to the normal condition (p < 0.001). After removal of the ICH and development of CVS, the compliance in the perifocal zone remains much lower (р = 0.003) as compared to compliance of the other brain hemisphere.

The Сerebrovascular Time Constant in Patients with Head Injury and Posttraumatic Cerebral Vasospasm.

The aim of the study was to assess the time constant of cerebral arterial bed in TBI patients with cerebral vasospasm (CVS) with and without intracranial hematomas (ICH).We examined 84 patients with severe TBI (mean 35 ± 15 years, 53 men and 31 women). The first group included 41 patients without ICH and the second group included 43 patients with epidural (7) and subdural (36) hematomas.Perfusion computed tomography (PCT) was performed in 1-12 days after TBI in the first group and in 2-8 days after craniotomy in the second group. Arteriovenous amplitude of regional cerebral blood volume oscillation was calculated as the difference of arterial and venous blood volume in the "region of interest." Mean arterial pressure was measured and the flow rate of middle cerebral artery was recorded with Transcranial Doppler after PCT. Time constant was calculated by the formula modificated by M. Kasprowicz. Results and Conclusion: The τ was shorter (p < 0.005) in both first and second group in comparison with normal values. The τ in the second group on ipsilateral side former hematoma with CVS was shorter than in the first group and in the second group on contralateral side former hematoma without CVS (р = 0.024).