Previous studies report contradicting age-related neurovascular coupling (NVC). Few studies assess postural effects, but less investigate relationships between age and NVC within different postures. Therefore, this study investigated the effect of age on NVC in different postures with varying cognitive stimuli. Beat-to-beat blood pressure, heart rate and end-tidal carbon dioxide were assessed alongside middle and posterior cerebral artery velocities (MCAv and PCAv, respectively) using transcranial Doppler ultrasonography in 78 participants (31 young-, 23 middle- and 24 older-aged) with visuospatial (VST) and attention tasks (AT) in various postures at two timepoints (T2 and T3). Between-group significance testing utilized one-way analysis-of-variance (ANOVA) (Tukey post-hoc). Mixed three-way/one-way ANOVAs explored task, posture, and age interactions. Significant effects of posture on NVC were driven by a 3.8% increase from seated to supine. For AT, mean supine %MCAv increase was greatest in younger (5.44%) versus middle (0.12%) and older-age (0.09%) at T3 (p = 0.005). For VST, mean supine %PCAv increase was greatest at T2 and T3 in middle (10.99%/10.12%) and older-age (17.36%/17.26%) versus younger (9.44%/8.89%) (p = 0.004/p = 0.002). We identified significant age-related NVC effects with VST-induced hyperactivation. This may reflect age-related compensatory processes in supine. Further work is required, using complex stimuli while standing/walking, examining NVC, aging and falls.

Introduction  Predicting the shape of the occluded middle cerebral artery (MCA) from the contralateral MCA might help catheterization in endovascular mechanical thrombectomy (EMT). Materials and Methods  We analyzed magnetic resonance (MR) angiography in 100 consecutive patients who had MR imaging for diseases other than acute ischemic stroke. To assess the symmetricity of MCA, the shape of M1, length of M1, number of M2, number of early branches (EBs), and distance from the top of the internal carotid artery to EB were investigated. Results  The shape of M1 was upward in 42%, horizontal in 47%, and downward in 11%. The M1 shape was the same on both sides in 64%, which exceeded the probability assumed to be left-right independent. The number of M2 trunks and EBs matched left and right in 86 and 55% of patients, respectively; however, these agreement rates were not higher than those with independent left and right sides. No left-right correlation was found between the M1 length and the distance from the internal carotid artery to EB. Conclusion  Based on our data, the symmetry of MCA was observed only in the shape of the M1 segment. This finding could be beneficial for EMT targeting MCA embolisms.

OBJECTIVE: Intracranial aneurysm growth is a significant risk factor for rupture; however, a few aneurysms remain unruptured for long periods, even after growth. Here, we identified hemodynamic features associated with aneurysmal rupture after growth.
METHODS: We analyzed nine middle cerebral artery aneurysms that grew during the follow-up period using computational fluid dynamics analysis. Growth patterns of the middle cerebral artery aneurysms were divided into homothetic growth (Type 1), de novo bleb formation (Type 2), and bleb enlargement (Type 3). Hemodynamic parameters of the four ruptured aneurysms after growth were compared with those of the five unruptured aneurysms.
RESULTS: Among nine aneurysms (78%), seven were Type 1, one was Type 2, and one was Type 3. Three (43%) Type 1 aneurysms ruptured after growth. Maximum oscillatory shear index after aneurysmal growth was significantly higher in ruptured Type 1 cases than in unruptured Type 1 cases (ruptured vs. unruptured: 0.455 ± 0.007 vs. 0.319 ± 0.042, p = 0.003). In Type 1 cases, a newly emerged high-oscillatory shear index area was frequently associated with rupture, indicating a rupture point. Aneurysm growth was observed in the direction of the high-pressure difference area before enlargement. In Types 2 and 3 aneurysms, the maximum oscillatory shear index decreased slightly, however, the pressure difference values remain unchanged. In Type 3 aneruysm, the maximum OSI and PD values remained unchanged.
CONCLUSIONS: This study suggests that hemodynamic variations and growth pattern changes are crucial in rupture risk determination using computational fluid dynamics analysis. High-pressure difference areas may predict aneurysm enlargement direction. Additionally, high maximum oscillatory shear index values after enlargement in cases with homothetic growth patterns were potential rupture risk factors.

Our study aimed to evaluate the postoperative outcome of patients with unruptured giant middle cerebral artery (MCA) aneurysm revealed by intracranial hypertension associated to midline brain shift. From 2012 to 2022, among the 954 patients treated by a microsurgical procedure for an intracranial aneurysm, our study included 9 consecutive patients with giant MCA aneurysm associated to intracranial hypertension with a midline brain shift. Deep hypothermic circulatory flow reduction (DHCFR) with vascular reconstruction was performed in 4 patients and cerebral revascularization with aneurysm trapping was the therapeutic strategy in 5 patients. Early (< 7 days) and long term clinical and radiological monitoring was done. Good functional outcome was considered as mRS score ≤ 2 at 3 months. The mean age at treatment was 44 yo (ranged from 17 to 70 yo). The mean maximal diameter of the aneurysm was 49 mm (ranged from 33 to 70 mm). The mean midline brain shift was 8.6 mm (ranged from 5 to 13 mm). Distal MCA territory hypoperfusion was noted in 6 patients. Diffuse postoperative cerebral edema occurred in the 9 patients with a mean delay of 59 h and conducted to a postoperative neurological deterioration in 7 of them. Postoperative death was noted in 3 patients. Among the 6 survivors, early postoperative decompressive hemicraniotomy was required in 4 patients. Good functional outcome was noted in 4 patients. Complete aneurysm occlusion was noted in each patient at last follow-up. We suggest to discuss a systematic decompressive hemicraniotomy at the end of the surgical procedure and/or a partial temporal lobe resection at its beginning to reduce the consequences of the edema reaction and to improve the postoperative outcome of this specific subgroup of patients. A better intraoperative assessment of the blood flow might also reduce the occurrence of the reperfusion syndrome.

UNASSIGNED: Traumatic middle cerebral artery (MCA) pseudoaneurysms following minor head trauma are rare.
UNASSIGNED: We report a case of a 76-year-old man who presented with a traumatic acute subdural hematoma and subarachnoid hemorrhage (SAH) from a ruptured distal right MCA pseudoaneurysm treated with evacuation of the hematoma, resection of the pseudoaneurysm, and an MCA-to-MCA bypass.
UNASSIGNED: Although traumatic pseudoaneurysms of the distal intracranial vessels are rare, patients with traumatic SAH would benefit from vascular imaging. Treatment of pseudoaneurysms of distal intracranial vessels may be treated with vessel occlusion or trapping/excision of aneurysm with revascularization.

Studies have shown cerebrovascular dysfunction in offspring with full-gestational electronic cigarette (Ecig) exposure, but little is known about how individual trimester exposure impacts offspring health. This study aimed to determine if there is a critical window during gestation that contributes to vascular and anxiety-like behavioural changes seen with full-term exposure. To test this, rats were time-mated, and the pregnant dams were randomly assigned to Ecig exposure during first trimester (gestational day, GD2-7), second trimester (GD8-14), third trimester (GD15-21) or full-term gestation (GD2-21). We also assessed the effect of maternal preconception exposure. Both male and female offspring from all maternal exposure conditions were compared to offspring from dams under ambient air (control) conditions. Ecig exposure consisted of 60-puffs/day (5 days/week) using either 5 or 30 watts for each respective exposure group. We found that maternal exposure to Ecig in the second and third trimesters resulted in a decrease (23-38%) in vascular reactivity of the middle cerebral artery (MCA) reactivity in 3- and 6-month-old offspring compared to Air offspring. Further, the severity of impairment was comparable to the full-term exposure (31-46%). Offspring also displayed changes in body composition, body mass, anxiety-like behaviour and locomotor activity, indicating that Ecigs influence neurodevelopment and metabolism. Maternal preconception exposure showed no impact on offspring body mass, anxiety-like behaviour, or vascular function. Thus, the critical exposure window where Ecig affects vascular development in offspring occurs during mid- to late-gestation in pregnancy, and both 5 W and 30 W exposure produce significant vascular dysfunction compared to Air. KEY POINTS: Exposure to electronic cigarettes (Ecigs) is known to increase risk factors for cardiovascular disease in both animals and humans. Maternal Ecig use during pregnancy in rodents is found to impair the vascular health of adolescent and adult offspring, but the critical gestation window for Ecig-induced vascular impairment is not known. This study demonstrates Ecig exposure during mid- and late-gestation (i.e. second or third trimester) results in impaired endothelial cell-mediated dilatation (i.e. middle cerebral artery reactivity) and alters anxiety-like behaviour in offspring. Maternal exposure prior to conception did not impact offspring\'s vascular or anxiety-like behavioural outcomes. Rodent models have been a reliable and useful predictor of inhalation-induced harm to humans. These data indicate maternal use of Ecigs during pregnancy should not be considered safe, and begin to inform clinicians and women about potential long-term harm to their offspring.

OBJECTIVE: After a traumatic brain injury (TBI), monitoring of both macrovascular and microvascular blood circulation can potentially yield a better understanding of pathophysiology of potential secondary brain lesions. We investigated the changes in phase shift (PS) between cardiac-induced oscillations of cerebral blood flow (CBF) measured at macro (ultrasound Doppler) and microvascular (laser Doppler) level. Further we assessed the impact of intracranial pressure (ICP) on PS in TBI patients. A secondary aim was to compare PS to TCD-derived cerebral arterial time constant (τ), a parameter that reflects the circulatory transit time.
METHODS: TCD blood flow velocities (FV) in the middle cerebral artery, laser Doppler blood microcirculation flux (LDF), arterial blood pressure (ABP), and ICP were monitored in 29 consecutive patients with TBI. Eight patients were excluded because of poor-quality signals. For the remaining 21 patients (median age = 23 (Q1: 20-Q3: 33); men:16,) data were retrospectively analysed. PS between the fundamental harmonics of FV and LDF signals was determined using spectral analysis. τ was estimated as a product of cerebrovascular resistance and compliance, based on the mathematical transformation of FV and ABP, ICP pulse waveforms.
RESULTS: PS was negative (median: -26 (Q1: -38-Q3: -15) degrees) indicating that pulse LDF at a heart rate frequency lagged behind TCD pulse. With rising mean ICP, PS became more negative (R = -0.51, p < 0.019) indicating that delay of LDF pulse increases. There was a significant correlation between PS and cerebrovascular time constant (R = -0.47, p = 0.03).
CONCLUSIONS: Pulse divergence between FV and LDF became greater with elevated ICP, likely reflecting prolonged circulatory travel time.

The long-term consequences of electronic cigarette (Ecig) use in humans are not yet known, but it is known that Ecig aerosols contain many toxic compounds of concern. We have recently shown that Ecig exposure impairs middle cerebral artery (MCA) endothelial function and that it takes 3 days for MCA reactivity to return to normal. However, the sources contributing to impairment of the endothelium were not investigated. We hypothesized that the increased levels of oxidative stress markers in the blood are correlated with impaired MCA reactivity. We used electron paramagnetic resonance (EPR) spectroscopy to examine plasma from 4-month-old male Sprague-Dawley rats that were exposed to either air (n = 5) or 1 h Ecig exposure, after which blood samples were collected at varying times after exposure (i.e., 1-4, 24, 48 and 72 h postexposure, n = 4 or 5 in each time group). The EPR analyses were performed using the redox-sensitive hydroxylamine spin probe 1-hydroxy-3-carboxymethyl-2,2,5,5-tetramethyl-pyrrolidine (CMH) to measure the level of reactive oxidant species in the plasma samples. We found that EPR signal intensity from the CM• radical was significantly increased in plasma at 1-4, 24 and 48 h (P < 0.05, respectively) and returned to control (air) levels by 72 h. When evaluating the EPR results with MCA reactivity, we found a significant negative correlation (Pearson\'s P = 0.0027). These data indicate that impaired cerebrovascular reactivity resulting from vaping is associated with the oxidative stress level (measured by EPR from plasma) and indicate that a single 1 h vaping session can negatively influence vascular health for up to 3 days after vaping. HIGHLIGHTS: What is the central question of this study? Does the time course of oxidative stress triggered by electronic cigarette exposure follow the cerebral vascular dysfunction? What is the main finding and its importance? Electron paramagnetic resonance analysis shows that the oxidative stress induced after a single 1 h exposure to electronic cigarette aerosol takes ≤72 h to return to normal, which mirrors the time course for vascular dysfunction in the middle cerebral artery that we have reported previously.

Permanent residence at high-altitude and chronic mountain sickness (CMS) may alter the cerebrovascular homeostasis and orthostatic responses. Healthy male participants living at sea-level (LL; n = 15), 3800 m (HL3800m; n = 13) and 5100 m (HL5100m; n = 17), respectively, and CMS highlanders living at 5100 m (n = 31) were recruited. Middle cerebral artery mean blood flow velocity (MCAv), cerebral oxygen delivery (CDO2), mean blood pressure (MAP), heart rate variability and spontaneuous cardiac baroreflex sensitivity (cBRS) were assessed while sitting, initial 30 s and after 3 min of standing. Cerebral autoregulation index (ARI) was estimated (ΔMCAv%baseline)/ΔMAP%baseline) in response to the orthostatic challenge. Altitude and CMS were associated with hypoxemia and elevated hemoglobin concentration. While sitting, MCAv and LFpower negatively correlated with altitude but were not affected by CMS. CDO2 remained preserved. BRS was comparable across all altitudes, but lower with CMS. Within initial 30 s of standing, altitude and CMS correlated with a lesser ΔMAP while ARI remained unaffected. After 3 min standing, MCAv, CDO2 and cBRS remained preserved across altitudes. The LF/HF ratio increased in HL5100m compared to LL and HL3800m from sitting to standing. In contrary, CMS showed blunted autonomic nervous activation in responses to standing. Despite altitude- and CMS-associated hypoxemia, erythrocytosis and impaired blood pressure regulation (CMS only), cerebral homeostasis remained overall preserved.

Transient ischemic attack (TIA) is an early warning sign of stroke and death, necessitating suitable animal models due to the associated clinical diagnostic challenges. In this study, we developed a TIA model using flexible spatially targeted photothrombosis combined with real-time blood flow imaging feedback. By modulating the excitation light using wavefront technology, we precisely created a square light spot (50 × 250 µm), targeted at the distal middle cerebral artery (dMCA). The use of laser speckle contrast imaging (LSCI) provided real-time feedback on the ischemia, while the excitation light was ceased upon reaching complete occlusion. Our results demonstrated that the photothrombus formed in the dMCA and spontaneously recanalized within 10 min (416.8 ± 96.4 s), with no sensorimotor deficits or infarction 24 h post-TIA. During the acute phase, ischemic spreading depression occurred in the ipsilateral dorsal cortex, leading to more severe ischemia and collateral circulation establishment synchronized with the onset of dMCA narrowing. Post-reperfusion, the thrombi were primarily in the sensorimotor and visual cortex, disappearing within 24 h. The blood flow changes in the dMCA were more indicative of cortical ischemic conditions than diameter changes. Our method successfully establishes a photochemical TIA model based on the dMCA, allowing for the dynamic observation and control of thrombus formation and recanalization and enabling real-time monitoring of the impacts on cerebral blood flow during the acute phase of TIA.