Search Results (27)

Increases in flow elicit dilations in the basilar artery (BA) supplied by the posterior cerebral circulation (PCC), and ensuring efficient blood supply to the circle of Willis in which blood flow and pressure can distribute and equalize, and thus provide the appropriate supply for the daughter branches to reach certain brain areas. In contrast, increases in flow elicit constrictions in the middle cerebral artery (MCA), supplied by the anterior cerebral circulation (ACC) and regulating the blood pressure and flow in distal cerebral circulation. Mediators of flow-dependent responses include arachidonic acid (AA) metabolites and nitric oxide (NO). We hypothesized that mediators of flow-dependent responses are differentially expressed in cerebral arteries of the PCC (CA_PCC) and ACC (CA_ACC). The expressions of key enzymes of the AA pathway—cyclooxygenases (COX1/COX2), cytochrome P450 hydroxylases (Cyp450), thromboxane synthase (TXAS), thromboxane A2 (TP) receptor, prostacyclin synthase (PGIS), prostacyclin (IP) receptor (IP); neuronal nitric oxide synthase (nNOS), and endothelial nitric oxide synthase (eNOS)—in the BA and MCA from rats (n = 20) were determined by western blotting. Transcriptome analysis in CA_PCC and CA_ACC from rats (n = 25) was assessed by RNA sequencing. In BA compared to MCA, COX1/2 and Cyp450 protein expressions were lower, PGIS was higher, TXAS and nNOS/eNOS were similar, TP receptors were lower, and IP receptors were higher. Gene expressions of vasodilator canonical pathways were higher in CA_PCC; vasoconstriction canonical pathways were higher in CA_ACC. Mediators of flow-dependent vasomotor signaling are differentially expressed in cerebral arteries of the posterior and anterior circulation, corresponding to their vasomotor function. Full article

Objective: Acute ischemic stroke (AIS) remains one of the most common causes of death and disability in the world. Mechanical thrombectomy (MT) is the modality of choice in the treatment of AIS and large vessel occlusion (LVO). The endovascular treatment of medium and distal vessel occlusions (DMVO) is currently under intensive scientific investigation. The aim of our study was to prove the feasibility, effectiveness and safety of MT in patients with a primary, isolated occlusion of the M2 segment of the middle cerebral artery (MCA), with a focus on the recanalization level and the first-pass effect (FPE) as predictors. Methods: We prospectively assessed patients after MT for primary isolated occlusion of the M2 MCA segment that were treated at our center during a three-year period between July 2021 and June 2024. Our final cohort included 137 patients who met the inclusion criteria. Epidemiological, clinical and technical data, as well as the clinical and safety outcomes of MT procedures, were recorded and analyzed. The primary outcome was defined as a modified Rankin scale (mRS) score of 0–2. Secondary outcomes included excellent functional independence (mRS 0–1) and successful recanalization, defined by a modified thrombolysis in cerebral infarction (mTICI) score of 2c–3. Safety outcomes included symptomatic intracerebral hemorrhage (sICH), any intracerebral (IC) hemorrhage and 90-day mortality. Results: The mean age of our cohort was 71.8 ± 12.5 years; 59 were men (43.1%). The primary outcome (mRS 0–2) was achieved in 89 (65%) patients. An excellent functional outcome (mRS 0–1) was reached in 58 (42.3%) and successful recanalization (mTICI 2c–3) in 118 (86.1%) patients. sICH was present in 5 cases (3.7%), any IC hemorrhage in 42 (30.7%) and 90-day mortality in 28 (20.4%). We found a statistically significant correlation between the primary outcome (mRS 0–2) and a successful recanalization mTICI of 2c–3 (p—0.024). This correlation was even stronger between excellent functional outcomes and a recanalization mTICI of 2c-3 (p < 0.001). The study did not confirm the importance of the first-pass effect (FPE) during MT of the M2 segment (p—0.489). We also noticed a significant 31.3% mortality increase in the group of patients in which recanalization of the occluded M2 branch was insufficient. Conclusions: MT is a powerful and effective treatment method for AIS caused by an occlusion of the M2 segment in real-life conditions. Patients have a higher probability of a long-term good functional outcome when complete or near-complete reperfusion is achieved. Full article

Background/Objectives: Cerebrovascular reactivity (CVR) and time shift (TS) are vascular-related parameters that reflect cerebral perfusion and may be associated with the risk of developing stroke in patients with asymptomatic carotid artery stenosis (ACAS). We investigated CVR and TS in patients with ACAS using resting-state magnetic resonance imaging based on blood-oxygen-level-dependent contrast (BOLD-MRI). Methods: We included twenty patients with severe unilateral ACAS and twenty age-matched controls. Individual CVR maps were obtained through a voxel-wise regression of the MRI signal, using the global signal filtered in a specific frequency range (0.02–0.04 Hz) as the regressor. A recursive cross-correlation method provided individual TS maps through the BOLD low-frequency fluctuation. CVR and TS values were obtained for the territories irrigated by the main cerebral arteries (anterior, middle, and posterior) separated into proximal, intermediary, and distal regions. Results: Compared to controls, ACAS patients presented reduced CVR and increased TS in the distal parts of the brain vascular territories. Individual CVR and TS values varied more within the patient group than controls. Such individual variability may help identify patients eligible for intervention better than the stenosis grade. Conclusions: CVR and TS may indicate subtle hemodynamic changes and assist in identifying regions at higher risk of neuronal damage or ischemic stroke on an individual basis, aiding in the stratification of patients with ACAS based on their risk of progressing to stroke. Full article

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. Full article

Despite growing evidence over the last few years of the efficacy and safety of direct thrombus aspiration using a large bore distal access catheter as a type of mechanical thrombectomy procedure in acute stroke large-vessel occlusion patients, the experience and evidence of this technique for managing thromboembolic complications in endovascular aneurysm treatment is still limited and little research is available regarding this topic. We present a case of a thromboembolic occlusion of the left middle cerebral artery during the preprocedural angiograms of a large and fusiform left internal carotid artery aneurysm. This complication was successfully managed by navigating an already-placed distal access catheter intended for support during the opening of the flow-diverting stent; therefore, the thrombus was manually aspirated for two minutes, and Thrombolysis in Cerebral Infarction (TICI) scale 3 flow was restored. This case should encourage the use of a distal access catheter, already placed for aneurysm treatment, to perform zero-delay direct thrombus aspiration as a rescue approach for thromboembolic complications during endovascular treatments. Full article

Cerebrovascular disease (CVD) poses a major public health and socio-economic burden worldwide due to its high morbidity and mortality rates. Accurate assessment of cerebral arteries’ haemodynamic plays a crucial role in the diagnosis and treatment management of CVD. The study compared a non-imaging transcranial Doppler ultrasound (TCD) and transcranial color-coded Doppler ultrasound (with (cTCCD) and without (ncTCCD)) angle correction in quantifying middle cerebral arteries (MCAs) haemodynamic parameters. A cross-sectional study involving 50 healthy adults aged ≥ 18 years was conducted. The bilateral MCAs were insonated via three trans-temporal windows (TTWs—anterior, middle, and posterior) using TCD, cTCCD, and ncTCCD techniques. The MCA peak systolic velocity (PSV) and mean flow velocity (MFV) were recorded at proximal and distal imaging depths that could be visualised on TCCD with a detectable spectral waveform. A total of 152 measurements were recorded in 41 (82%) subjects with at least one-sided open TTW across the three techniques. The mean PSVs measured using TCD, ncTCCD, and cTCCD were 83 ± 18 cm/s, 81 ± 19 cm/s, and 93 ± 21 cm/s, respectively. There was no significant difference in PSV between TCD and ncTCCD (bias = 2 cm/s, p = 1.000), whereas cTCCD yielded a significantly higher PSV than TCD and ncTCCD (bias = −10 cm/s, p < 0.001; bias = −12 cm/s, p ≤ 0.001, respectively). The bias in MFV between TCD and ncTCCD techniques was (bias = −0.5 cm/s; p = 1.000), whereas cTCCD demonstrated a higher MFV compared to TCD and ncTCCD (bias = −8 cm/s, p < 0.001; bias = −8 cm/s, p ≤ 0.001, respectively). TCCD is a practically applicable imaging technique in assessing MCA blood flow velocities. cTCCD is more accurate and tends to give higher MCA blood flow velocities than non-imaging TCD and ncTCCD techniques. ncTCCD is comparable to non-imaging TCD and should be considered in clinical cases where using both TCD and TCCD measurements is needed. Full article

(1) Background: to test the diagnostic performance of a fully convolutional neural network-based software prototype for clot detection in intracranial arteries using non-enhanced computed tomography (NECT) imaging data. (2) Methods: we retrospectively identified 85 patients with stroke imaging and one intracranial vessel occlusion. An automated clot detection prototype computed clot location, clot length, and clot volume in NECT scans. Clot detection rates were compared to the visual assessment of the hyperdense artery sign by two neuroradiologists. CT angiography (CTA) was used as the ground truth. Additionally, NIHSS, ASPECTS, type of therapy, and TOAST were registered to assess the relationship between clinical parameters, image results, and chosen therapy. (3) Results: the overall detection rate of the software was 66%, while the human readers had lower rates of 46% and 24%, respectively. Clot detection rates of the automated software were best in the proximal middle cerebral artery (MCA) and the intracranial carotid artery (ICA) with 88–92% followed by the more distal MCA and basilar artery with 67–69%. There was a high correlation between greater clot length and interventional thrombectomy and between smaller clot length and rather conservative treatment. (4) Conclusions: the automated clot detection prototype has the potential to detect intracranial arterial thromboembolism in NECT images, particularly in the ICA and MCA. Thus, it could support radiologists in emergency settings to speed up the diagnosis of acute ischemic stroke, especially in settings where CTA is not available. Full article

Background: Our previous research revealed that inflammation plays an important role in the pathophysiology of cerebral ischemia. The function of the NOD-like receptor protein 3 (NLRP3) inflammasome is to activate the inflammatory process. Recent findings suggest that reactive oxygen species (ROS) are essential secondary messengers that activate the NLRP3 inflammasome. Hydrogen-rich saline (HS) has attracted attention for its anti-inflammatory properties. However, the protective effect and possible mechanism of HSin brain ischemia have not been well elucidated. Methods: To test the therapeutic effect of HS, we established a mouse model of distal middle cerebral artery occlusion (dMCAO) and an in vitro model of BV2 cells induced by lipopolysaccharide (LPS). The ROS scavenger N-acetylcysteine (NAC) was used to investigate the underlying mechanisms of HS. Results: HS significantly improved neurological function, reduced infarct volume, and increased cerebral blood flow in a dMCAO mouse model. ROS, NLRP3, Caspase-1, and IL-1β expression increased after cerebral ischemia, and this was reversed by HS treatment. In BV2 cells, the application of NAC further demonstrated that HS could effectively inhibit the expression of the ROS-activated NLRP3 inflammasome. Conclusions: HS, as a novel therapeutic option, could exert protect the brain by inhibiting the activation of the ROS-NLRP3 signaling pathway after cerebral ischemia. Full article

Motor rehabilitation strategies after unilateral stroke suggest that the immobilization of the healthy, unimpaired limb can promote the functional recovery of a paretic limb. In rodents, this has been modeled using casts, harnesses, and other means of restricting the use of the non-paretic forelimb in models of experimental stroke. Here, we evaluated an alternative approach, using botulinum toxin injections to limit the function of the non-paretic forelimb. Adult male rats were subjected to permanent ligation of the left distal middle cerebral artery, resulting in right forelimb paresis. The rats were then subjected to: (1) no treatment; (2) botulinum toxin injections 1 day post stroke; or (3) cast placement 5 days post stroke. Casts were removed after 5 weeks, while the botulinum toxin injection effectively immobilized subjects for approximately the same duration. Rats with bilateral forelimb impairment due to the stroke plus casting or botulinum injections were still able to feed and groom normally. Both immobilization groups showed modest recovery following the stroke compared to those that did not receive immobilization, but the casting approach led to unacceptable levels of animal stress. The botulinum toxin approach to limb immobilization had both advantages and disadvantages over traditional physical limb immobilization. The major advantage was that it was far less stress-inducing to the subject animals and appeared to be well tolerated. A disadvantage was that the paresis took roughly 10 weeks to fully resolve, and any degree of residual paresis could confound the interpretation of the behavioral assessments. Full article

Purpose: Thrombus permeability has been related to clot composition and treatment outcomes in stroke patients undergoing reperfusion therapies. The aim of this study was to evaluate whether thrombus perviousness, evaluated by multiphase computed tomography angiography (mCTA), is associated with distal embolization risk. Methods: We interrogated our dataset of acute ischemic stroke (AIS) patients involving the M1 segment of the middle cerebral artery (MCA) who had undergone mechanical thrombectomy, and we calculated thrombus average attenuation measurement (dHU) on non-contrast CT (NCCT) and clot perviousness on mCTA. dHU was calculated as the difference between the thrombus HU average value (tHU) and the HU average value on the contralateral side (cHU), while perviousness was calculated as the difference in mean clot density on mCTA and NCCT both in arterial (Perviousness pre-post-1) and delayed (Perviousness pre-post 2) phases. Results: A total of 100 patients (53 females (53%), mean age 72.74 [± 2.31]) with M1 occlusion were available for analysis. Perviousness, calculated between baseline and arterial phase of mCTA (Perviousness pre-post1), was lower in patients with distal embolization (p = 0.05), revealing an association between reduced perviousness and distal embolization risk. Logistic regression showed that thrombus perviousness calculated on the arterial phase of mCTA (OR, 0.66; 95% CI, 0.44–0.99] (p = 0.04)) and the contact aspiration technique (OR, 0.39; 95% CI, 0.15–1.02] (p = 0.05)) were protecting factors against distal embolization. Conclusion: Our study showed an association between reduced perviousness and distal embolization, suggesting that perviousness evaluation may be a useful neuroimaging biomarker in predicting distal embolization risk during mechanical thrombectomy. Full article

Thoracic outlet syndrome (TOS) is a condition that results from the compression of neurovascular structures as they exit the thorax. Arterial ischemic stroke can occur in TOS due to retrograde embolism from the subclavian artery. We describe a 15-year-old girl who presented with left hemiplegia after 2 weeks of right arm numbness and tingling. Imaging showed an acute ischemic stroke due to a right middle cerebral artery occlusion. She was treated with intravenous tissue plasminogen activator at 1.3 h and mechanical thrombectomy at 2.4 h with successful recanalization. Review of her neck computed tomography angiogram suggested a right subclavian artery aneurysm, and upper-extremity imaging also demonstrated distal thrombosis and fusion of right first and second ribs, which was consistent with thoracic outlet syndrome. Three days later, she underwent a right subclavian artery aneurysm repair, right brachial and ulnar artery thrombectomy, and first rib resection. Three months later, she demonstrated good neurologic recovery. TOS is an uncommon cause of stroke in children, which may be heralded by upper-extremity symptoms. Interventionalists should be aware of the possibility of vascular anomalies in children; however, this finding does not exclude the possibility of acute stroke intervention. Full article

Background: Vessel perforation during stent mechanical thrombectomy (MT) is a rare and disastrous complication. A routine rescue strategy includes balloon occlusion for tamponade, procedure suspension, and lowering or normalizing blood pressure. However, this complication is still associated with poor outcome and high mortality. Objective: We present our experience with intra-arterial injection of thrombin in the treatment of vessel perforation secondary to microcatheter/microwire perforation, which prevents further deterioration in clinical outcomes. Methods: Cases with intraprocedural vessel perforation during mechanical thrombectomy were included in the final analysis. Clinical data, procedural details, and radiographic and clinical outcomes were collected. Results: Four patients with intraprocedural vessel perforation were included. Intraprocedural perforations occurred at the distal middle cerebral artery in two cases: the A2 segment in one case and the internal carotid artery terminus in one case. The etiology of four cases was intracranial atherosclerotic stenosis (ICAS). The ruptured vessels were effectively occluded in all cases. Endovascular therapy was continued in three cases, and mTICI ≥ 2b recanalization was achieved in all cases. The culprit artery was kept patent on CTA for 72 h post-operation. No active bleeding was detected on follow-up CT post-operation. During the 90-day follow-up period, one patient died, modified Rankle Scare (mRS) 3 was observed in two patients, and mRS 4 was observed in one patient. Conclusions: The key benefit of this method is occluding the ruptured vessel without affecting the following MT. We propose that intra-arterial injection of prothrombin may be simple yet effective in managing vessel perforation complications during MT. Full article

The brain area which surrounds the frankly ischemic region is named the area penumbra. In this area, most cells are spared although their oxidative metabolism is impaired. area penumbra is routinely detected by immunostaining of a molecule named Heat Shock Protein 70 (HSP70). Within the area penumbra, autophagy-related proteins also increase. Therefore, in the present study, the autophagy-related microtubule-associated protein I/II-Light Chain 3 (LC3) was investigated within the area penumbra along with HSP70. In C57 black mice, ischemia was induced by permanent occlusion of the distal part of the middle cerebral artery. Immunofluorescence and electron microscopy show that LC3 and HSP70 are overexpressed and co-localize within the area penumbra in the same cells and within similar subcellular compartments. In the area penumbra, marked loss of co-localization of HSP70 and LC3-positive autophagy vacuoles, with lysosomal-associated membrane protein 1 (LAMP1) or cathepsin-D-positive lysosome vacuoles occurs. This study indicates that, within the area penumbra, a failure of autophagolysosomes depends on defective compartmentalization of LC3, LAMP1 and cathepsin-D and a defect in merging between autophagosomes and lysosomes. Such a deleterious effect is likely to induce a depletion of autophagolysosomes and cell clearing systems, which needs to be rescued in the process of improving neuronal survival. Full article

Neonatal and adult strokes are more common in the left than in the right cerebral hemisphere in the middle cerebral arterial territory, and adult extracranial and intracranial vessels are systematically left-dominant. The aim of the research reported here was to determine whether the asymmetric vascular ground plan found in adults was present in healthy term neonates (n = 97). A new transcranial Doppler ultrasonography dual-view scanning protocol, with concurrent B-flow and pulsed wave imaging, acquired multivariate data on the neonatal middle cerebral arterial structure and function. This study documents for the first-time systematic asymmetries in the middle cerebral artery origin and distal trunk of healthy term neonates and identifies commensurately asymmetric hemodynamic vulnerabilities. A systematic leftward arterial dominance was found in the arterial caliber and cortically directed blood flow. The endothelial wall shear stress was also asymmetric across the midline and varied according to vessels’ geometry. We conclude that the arterial structure and blood supply in the brain are laterally asymmetric in newborns. Unfavorable shearing forces, which are a by-product of the arterial asymmetries described here, might contribute to a greater risk of cerebrovascular pathology in the left hemisphere. Full article

Atrial fibrillation and cerebral embolism are known to increase the risk of hemorrhagic transformation (HT). In addition, a sufficient number of collateral vessels in acute ischemic stroke can maintain the ischemic penumbra and prevent progression to the ischemic core, while an insufficient number of collateral vessels increase the HT risk after therapeutic recanalization. In this case, when the middle cerebral artery is recanalized, reperfusion injury may occur in the basal ganglia due to insufficient collateral vessels. Full article