Search Results (287)

Background/Objectives: Posterior inferior cerebellar artery (PICA) aneurysms are one of the most difficult cerebrovascular lesions to treat and account for 0.5–3% of all intracranial aneurysms. They have deep anatomical locations, broad-neck configurations, high perforator density, and a close association with the brainstem, which creates considerable technical challenges for either microsurgical or endovascular treatment. Despite its acceptance as the standard of care for most posterior circulation aneurysms, PICA aneurysms are often associated with flow diversion using a coil or flow diversion due to incomplete occlusions, parent vessel compromise and high rate of recurrence. This case aims to describe the utility of microsurgical clipping as a durable and definitive option demonstrating the value of tailored surgical planning, preservation of anatomy and ancillary technologies for protecting a genuine outcome in ruptured PICA aneurysms. Methods: A 66-year-old male was evaluated for an acute subarachnoid hemorrhage from a ruptured and broad-necked fusiform left PICA aneurysm at the vertebra–PICA junction. Endovascular therapy was not an option due to morphology and the center of the recurrence; therefore, a microsurgical approach was essential. A far-lateral craniotomy with a partial C1 laminectomy was carried out for proximal vascular control, with careful dissection of the perforating arteries and precise clip application for the complete exclusion of the aneurysm whilst preserving distal PICA flow. Results: Post-operative imaging demonstrated the complete obliteration of the aneurysm with unchanged cerebrovascular flow dynamics. The patient had progressive neurological recovery with no new cranial nerve deficits or ischemic complications. Long-term follow-up demonstrated stable aneurysm exclusion and full functional independence emphasizing the sustainability of microsurgical intervention in challenging PICA aneurysms. Conclusions: This case intends to highlight the current and evolving role of microsurgical practice for treating posterior circulation aneurysms, particularly at a time when endovascular alternatives are limited by anatomy and hemodynamics. Advances in artificial intelligence cerebral aneurysm rupture prediction, high-resolution vessel wall imaging, robotic-assisted microsurgery and new generation flow-modifying implants have the potential to revolutionize treatment paradigms by embedding precision medicine principles into aneurysm management. While the discipline of cerebrovascular surgery is expanding, it can be combined together with microsurgery, endovascular technologies and computational knowledge to ensure individualized, durable, and minimally invasive treatment options for high-risk PICA aneurysms. Full article

MRI perfusion is used to diagnose and monitor neurological conditions such as brain tumors, stroke, dementia, and traumatic brain injury. Dynamic Susceptibility Contrast (DSC) is the most widely available quantitative MRI technique for perfusion imaging. Even in its most basic implementation, DSC MRI provides critical hemodynamic metrics like cerebral blood flow (CBF), blood volume (CBV), mean transit time (MTT), and time between the peak of arterial input and residue function (Tmax), through the dynamic tracking of a gadolinium-based contrast agent. Notwithstanding its high clinical importance and widespread use, the reproducibility and diagnostic reliability are impeded by a lack of standardized pre-processing protocols and quality controls. A comprehensive literature review and the authors’ aggregated experience identified common DSC MRI artefacts and corresponding pre-processing methods. Pre-processing methods to correct for artefacts were evaluated for their practical applicability and validation status. A consensus on the pre-processing was established by a multidisciplinary team of experts. Acquisition-related artefacts include geometric distortions, slice timing misalignment, and physiological noise. Intrinsic artefacts include motion, B₁ inhomogeneities, Gibbs ringing, and noise. Motion can be mitigated using rigid-body alignment, but methods for addressing B₁ inhomogeneities, Gibbs ringing, and noise remain underexplored for DSC MRI. Pre-processing of DSC MRI is critical for reliable diagnostics and research. While robust methods exist for correcting geometric distortions, motion, and slice timing issues, further validation is needed for methods addressing B₁ inhomogeneities, Gibbs ringing, and noise. Implementing adequate mitigation methods for these artefacts could enhance reproducibility and diagnostic accuracy, supporting the growing reliance on DSC MRI in neurological imaging. Finally, we emphasize the crucial importance of pre-scan quality assurance with phantom scans. Full article

Artificial intelligence (AI) is revolutionizing the field of medical imaging, offering unprecedented capabilities in data analysis, image interpretation, and decision support. Transcranial Doppler (TCD) and Transcranial Color-Coded Doppler (TCCD) are widely used, non-invasive modalities for evaluating cerebral hemodynamics in acute and chronic conditions. Yet, their reliance on operator expertise and subjective interpretation limits their full potential. AI, particularly machine learning and deep learning algorithms, has emerged as a transformative tool to address these challenges by automating image acquisition, optimizing signal quality, and enhancing diagnostic accuracy. Key applications reviewed include the automated identification of cerebrovascular abnormalities such as vasospasm and embolus detection in TCD, AI-guided workflow optimization, and real-time feedback in general ultrasound imaging. Despite promising advances, significant challenges remain, including data standardization, algorithm interpretability, and the integration of these tools into clinical practice. Developing robust, generalizable AI models and integrating multimodal imaging data promise to enhance diagnostic and prognostic capabilities in TCD and ultrasound. By bridging the gap between technological innovation and clinical utility, AI has the potential to reshape the landscape of neurovascular and diagnostic imaging, driving advancements in personalized medicine and improving patient outcomes. This review highlights the critical role of interdisciplinary collaboration in achieving these goals, exploring the current applications and future directions of AI in TCD and TCCD imaging. This review included 41 studies on the application of artificial intelligence (AI) in neurosonology in the diagnosis and monitoring of vascular and parenchymal brain pathologies. Machine learning, deep learning, and convolutional neural network algorithms have been effectively utilized in the analysis of TCD and TCCD data for several conditions. Conversely, the application of artificial intelligence techniques in transcranial sonography for the assessment of parenchymal brain disorders, such as dementia and space-occupying lesions, remains largely unexplored. Nonetheless, this area holds significant potential for future research and clinical innovation. Full article

Background/Objectives: Assessment of the hemodynamic status of the brain in patients with cerebrovascular diseases is crucial for providing valuable clinical information. Various magnetic resonance perfusion sequences are used in studies, and one of the current challenges is comparing methods utilizing exogenous and endogenous contrast. This meta-analysis aimed to evaluate the correlation between arterial spin labeling (ASL)-derived perfusion parameters and those obtained by dynamic susceptibility contrast (DSC) perfusion in stroke and steno-occlusive diseases. Methods: A systematic review and meta-analysis were conducted, including 14 studies that reported correlation coefficients between perfusion MRI sequences in the assessment of stroke or steno-occlusive diseases. The correlation between ASL-derived cerebral blood flow (ASL-CBF) and DSC-derived cerebral blood flow (DSC-CBF) was analyzed, considering different magnetic field strengths (1.5 T and 3.0 T), sequence types, and brain regions. Additionally, real and normalized data were compared. Results: A moderate positive correlation was found between ASL-CBF and DSC-CBF (R = 0.464). Subgroup analysis demonstrated that ASL-CBF and DSC-CBF correlated at 3.0 T (R = 0.401) and 1.5 T (R = 0.700). No significant differences were observed in correlation coefficients based on sequence type or brain region. Normalized data demonstrated a higher correlation coefficient compared to real data (Rreal = 0.393, Rnorm = 0.496). Additionally, the correlation coefficient between ASL-CBF and DSC-derived mean transit time (DSC-MTT) for all included studies was R = −0.422. Conclusions: ASL-derived perfusion parameters demonstrate moderate-to-high agreement with DSC perfusion parameters in stroke and steno-occlusive patients. These findings support the potential utility of ASL as a non-invasive alternative to DSC perfusion imaging in clinical and research settings. Full article

Background: Despite the success of transcatheter aortic valve repair (TAVR) over the past years, its impact on global and cerebral hemodynamics remains largely unexplored. Changes in cerebral blood flow may be associated with delirium, which may occur in 26 to 29% of cases. We aimed to examine the relationships between global hemodynamic parameters and cerebral parameters in patients who underwent TAVR and their impact on postinterventional delirium. Methods: Patients scheduled for TAVR were enrolled after obtaining written informed consent. Patients received light sedation according to standard procedures. Cerebral blood flow (CBF) was measured with a noninvasive near-infrared spectroscopy-based method using intravenous indocyanine green injection. CBF measurements were taken at the beginning of the TAVR procedure and after the valve was in place. Patients were screened for delirium using CAM-ICU and NuDESC tests before and after intervention. Results: A total of 52 of 60 patients remained for analysis. Thirteen patients (25%) developed delirium. Mean arterial pressure (MAP) remained unchanged, while cardiac output increased after TAVR by 44%. CBF also increased after TAVR. No significant difference was observed in CBF changes between the groups with and without delirium. A linear mixed model analysis revealed a linear relationship between CO and CBF but not between MAP and CBF. In an exploratory analysis, decreased cerebral oxygenation and increased deoxygenated hemoglobin, as measured by NIRS after TAVR, were associated with delirium. Conclusions: The results confirm that CO is an independent factor in CBF, while CBF changes per se are not linked to delirium. However, we found a mismatch between CBF and regional cerebral parameters, which may reflect cerebral metabolism and its relation to the development of delirium. This remains to be confirmed by further studies. Full article

Background: Cranial Doppler ultrasonography (DS) is a non-invasive method for evaluating cerebral hemodynamics in neonates with perinatal asphyxia (PA). This study aimed to assess whether cerebral vascular resistance indices (RIs) measured within the first 24 h of life can predict the severity of brain injury. Methods: DS was performed on the anterior cerebral artery (ACA) and middle cerebral artery (MCA) between 6 and 24 h after birth in newborns diagnosed with PA. Prognostic value was evaluated by comparing RI values with cranial magnetic resonance imaging (MRI) results. Results: Of the 107 infants included in the study, 11 (10.3%) had severe brain damage, 27 (25.2%) had mild and 20 (18.7%) had moderate changes. The mean ACA RI was 0.61 ± 0.15 in the severe group and 0.70 ± 0.12 in the mild–moderate group (p = 0.023). MCA RI was 0.63 ± 0.20 and 0.71 ± 0.13, respectively. ROC analysis showed an area under the curve (AUC) of 0.901 for ACA RI with a cut-off of 0.58 (84% sensitivity and 84% specificity), and 0.874 for MCA RI with a cut-off of 0.59 (83% sensitivity and 84% specificity). Conclusions: Early ACA and MCA RI measurements via Doppler ultrasonography may serve as valuable predictors of brain injury severity in neonates with PA and should be considered alongside other clinical and imaging findings. Full article

Background/Objectives: Surgical aortic valve replacement effectively relieves left ventricular afterload and promotes reverse remodeling in patients with severe aortic stenosis. The Perceval prosthesis offers a hybrid approach, combining complete annular decalcification with sutureless deployment. This design allows for reduced operative times and potentially larger effective orifice areas. However, comparative data with conventional stented bioprosthetic valves remain limited, particularly regarding reverse remodeling, hemodynamic performance, and long-term clinical outcomes. Methods: In this retrospective cohort study, 115 patients underwent aortic valve replacement with either the Perceval valve (n = 44) or conventional stented bovine pericardial valves (n = 71). Results: The Perceval group showed a 100% procedural success rate with no in-hospital mortality, significantly shorter cardiopulmonary bypass and cross-clamp times, larger effective orifice areas, and a lower incidence of patient–prosthesis mismatch. Both groups demonstrated favorable left ventricular mass regression and reverse remodeling. The rates of paravalvular leakage, permanent pacemaker implantation, and redo aortic valve replacement were comparable between groups. Multivariate Cox regression identified the follow-up indexed left ventricular mass as an independent predictor of major adverse cardiac and cerebral events. Conclusions: In this study, the Perceval valve was associated with promising hemodynamic characteristics and procedural efficiencies, particularly in cases with small aortic annuli and during minimally invasive procedures. The valve was associated with reverse ventricular remodeling and clinical outcomes that appeared similar to those of conventional stented bioprostheses. These observations suggest it may represent a potential alternative option for surgical aortic valve replacement in appropriate clinical scenarios. However, randomized control trials are needed to confirm these associations. Full article

A brain aneurysm is a structural deterioration of the arterial wall in the brain, resulting in the formation of a bulge in or ballooning of a blood vessel. Around 3–5% of the global population is affected by brain aneurysms, wherein only a small fraction results in rupture. Although an unruptured aneurysm is typically asymptomatic and not immediately life threatening, it poses a potential risk of rupture, which can lead to severe health complications or mortality. Therefore, it is crucial to detect and treat aneurysms during the unruptured phase. Moreover, a comprehensive understanding of the flow dynamics within the aneurysm and its parent artery is essential for accurate diagnosis and the prevention of aneurysm recurrence. While prior reviews have focused on computational fluid dynamics (CFD) studies on brain aneurysms, particularly patient-specific models from studies conducted over a decade ago, a more recent review is necessary. Additionally, reviewing various studies on the fluid dynamic behavior of treated aneurysms is crucial. Thus, the advancements in both experimental and computational studies on brain aneurysms must be explored to better understand their underlying fluid flow mechanisms and to develop robust treatment strategies. This review aims to summarize the different types of brain aneurysms, the screening and treatment processes, the key hemodynamic factors, and the fluid dynamic characteristics observed in aneurysms before and after treatment. Full article

Background: Near-Infrared Spectroscopy (NIRS) and Electrical Cardiometry (EC) are promising non-invasive techniques for monitoring tissue oxygenation and hemodynamics, particularly in surgically ill infants who struggle to maintain cerebral oxygenation and systemic perfusion. There is limited data regarding the combined use of these techniques during respiratory procedures such as endotracheal suction in intubated infants. Methods: The effects of 38 endotracheal suction maneuvers on cerebral oxygenation and cardiovascular hemodynamics were investigated in seven intubated infants following non-cardiac surgery. Parameters such as cerebral oxygenation and EC-derived metrics including heart rate, stroke volume, and cardiac output were assessed. Results: Gestational and postnatal age were 31 weeks and 16 days. During endotracheal suction, the heart rate decreased but returned to baseline afterward. After the procedure, the cerebral oxygenation, stroke volume, and cardiac output increased. Conclusions: Cerebral and systemic hemodynamics were altered during endotracheal suction maneuvers in ventilated infants. Combining NIRS and EC for monitoring cardiovascular and cerebrovascular physiology may enable more individualized therapy, helping to minimize cerebral injury in this vulnerable population. Full article

Background/Objectives: Glaucoma and Alzheimer’s disease (AD) are neurodegenerative conditions with vascular underpinnings. This study aimed to explore the relationship between blood pressure parameters such as mean arterial pressure (MAP), pulse pressure (PP), and cerebral perfusion pressure (CPP) and cognitive performance in patients with AD, normal-tension glaucoma (NTG), and healthy controls. We hypothesized that NTG patients, like those with mild cognitive impairment (MCI), may experience subtle cognitive changes related to vascular dysregulation. Methods: Ninety-eight participants (35 NTG, 17 AD, 46 controls) were assessed for CPP, MAP, OPP, and cognitive performance. Statistical analyses compared groups and examined correlations. Results: AD patients showed lower CPP and MAP (p < 0.001), indicating systemic vascular dysfunction, while NTG patients had higher ocular perfusion pressure (OPP) (p = 0.008), suggesting compensatory mechanisms. CPP correlated with visuospatial abilities in AD (r = 0.492, p = 0.045). MAP correlated with the Clock drawing test (CDT) scores in the NTG group (r = 0.378, p = 0.025). PP negatively correlated with cognition in AD (r = −0.527, p = 0.016 for CDT scores) and controls (r = −0.440, p = 0.002 for verbal fluency and r = −0.348, p = 0.019 for total ACE scores). Conclusions: The study highlights distinct hemodynamic profiles: systemic dysfunction in AD and localized dysregulation in NTG. These findings emphasize the role of vascular dysregulation in neurodegeneration, with implications for personalized treatment approaches targeting vascular health in neurodegenerative conditions. Full article

Background/Objectives: The fetal-type posterior cerebral artery (fetal PCA) is an anatomical variant that alters hemodynamics and may influence posterior communicating artery (PCoA) aneurysm rupture risk. Aneurysm shape and size irregularity are key rupture predictors. This study investigates the impact of fetal PCA on PCoA aneurysm morphology and rupture risk using a radiomics-based approach. Methods: We retrospectively analyzed 87 patients with PCoA aneurysms (39 ruptured, 48 unruptured) treated at a tertiary center (January 2017–December 2022). Seventeen morphological parameters and 18 radiomic features were extracted per aneurysm. Patients were grouped by fetal PCA presence. Logistic regression and receiver operating characteristic (ROC) analyses identified rupture predictors. Results: Of 87 aneurysms, 38 had fetal PCA (24 ruptured, 14 unruptured), and 49 did not (15 ruptured, 34 unruptured). Fetal PCA was significantly associated with rupture (odds ratio [OR]: 3.28, p = 0.018). A higher non-sphericity index (NSI) correlated with rupture risk (OR: 3.35, p = 0.016). In non-fetal PCA aneurysms, size-related parameters such as height (6.83 ± 3.54 vs. 4.88 ± 2.57 mm, p = 0.034) and area (190.84 ± 167.08 vs. 107.94 ± 103.10 mm², p = 0.046) were key rupture predictors. In fetal PCA aneurysms, flow-related parameters like vessel angle (55.78 ± 31.39 vs. 38.51 ± 24.71, p = 0.035) were more influential. ROC analysis showed good discriminatory power, with an area under the curve: 0.726 for fetal PCA and 0.706 for NSI. Conclusions: Fetal PCA influences PCoA aneurysm rupture risk and morphology. NSI is a reliable rupture marker. Integrating morphological and anatomical data may improve rupture risk assessment and clinical decision-making. Full article

The usage of plastics in life and industrial applications has led to global environmental pollution by micro- and nanoplastics (MPs/NPs). Despite their widespread occurrence in the environment, little is known about their presence in humans and the potential implications for human health, particularly maternal and fetal health during the prenatal and neonatal periods. Studies on experimental animals indicate that exposure to MPs/NPs can lead to neurological abnormalities in offspring and hemodynamic alterations in the placenta and fetal cerebral arteries. These findings underscore the need for further epidemiological studies that examine the effects of MPs/NPs on fetal health during pregnancy, a critical period for neurological development. This review summarizes the existing knowledge on the effects of prenatal exposure to MPs/NPs on fetal development and birth outcomes in humans and provides a detailed overview of the challenges encountered in contamination prevention, quality assurance and quality control in analytical procedures. It also discusses the sampling and digestion methods used for the extraction of MPs/NPs from biological samples of maternal and fetal origin, highlighting the difficulties associated with accurately quantifying these particles in complex biological matrices, identifying the gaps in current research, and suggesting recommendations to improve methodologies for assessing the risks associated with prenatal MP/NP exposure. Full article

Background: Hyperintense vessels (HVs) visualized on FLAIR MRI are believed to reflect sluggish antegrade or retrograde flow in leptomeningeal collaterals that develop in response to major intracranial artery stenosis or occlusion. HV is frequently observed in conditions such as Moyamoya disease and symptomatic ICA/MCA steno-occlusion. However, the relationship between HV and cerebral hemodynamics—and the effect of STA-MCA bypass on HV—remains inadequately characterized. This study aimed to investigate the relationship between HV on FLAIR and cerebral vascular hemodynamic status, as measured by SPECT, in patients with Moyamoya disease and symptomatic ICA/MCA occlusion. The secondary goal was to assess the impact of recanalization through STA-MCA bypass surgery on the presence of HV. Methods: We retrospectively analyzed 49 patients with symptomatic ICA or MCA steno-occlusion who underwent STA-MCA bypass between 2015 and 2020. Pre- and postoperative FLAIR MRIs were evaluated, and HV presence was graded as negative (0), minimal (1), or positive (2). SPECT was utilized to assess cerebrovascular reserve (CVR) in regions exhibiting various HV intensities. Follow-up FLAIR imaging was performed 3–14 months postoperatively to correlate HV changes with hemodynamic improvements observed via SPECT. Result: HV was present in 74% (36/49) of affected hemispheres. Regions exhibiting minimal or positive HV demonstrated a significantly lower CVR compared to HV-negative areas, indicating compromised perfusion. Following bypass surgery, HV was reduced or resolved in 65% (32/49) of patients, and this regression corresponded with improved CVR as confirmed by both SPECT and perfusion MRI. Conclusions: HV presence on FLAIR imaging is associated with impaired cerebrovascular hemodynamics in patients with Moyamoya disease or symptomatic large-vessel steno-occlusion. HV-positive territories exhibit reduced CVR, while surgical revascularization via STA-MCA bypass leads to hemodynamic improvement and concurrent HV reduction. These findings support HV as a potential surrogate marker for treatment response. Full article

Simultaneous eye tracking and cerebral hemodynamic monitoring contribute to the understanding of neural responses to stimuli in infants. However, exploring the impact of complex socioeconomic and environmental adversities on neurodevelopment requires transitioning this tool from research laboratories into clinical practice to evaluate its feasibility in outpatient contexts. Background/Objectives: This study aimed to present a protocol for simultaneously integrating functional near-infrared spectroscopy (fNIRS) with eye tracking (ET) in infants at risk for neurodevelopmental disorders in a clinical setting with limited resources, during a cognitive task. Methods:The protocol was applied to infants in their first 12 months of life. The infants were exposed to tasks involving the processing of social and non-social stimuli, while their brain signals were monitored using fNIRS and their eyes were tracked with ET. The protocol included three main stages: (1) pre-collection, involving the preparation and habituation of the infants and equipment setup (fNIRS and ET); (2) cognitive function monitoring, using social and non-social stimuli to assess preferential processing via fNIRS and ET; and (3) post-collection, with guidelines for data pre-processing and analysis. Results: The application of the protocol allowed for the identification of technical challenges and the adaptation of procedures for clinical use. The main methodological challenges were difficulty using the conventional cap, excessive movement, synchronization issues between fNIRS and ET, and difficulties calibrating both devices across different age groups. Conclusions: The standardization proposed in this protocol enables healthcare professionals to explore different neurocognitive aspects in pediatric clinical settings and expands the scope of neurodevelopmental assessments. Full article

Background and Objectives: Carotid artery stenosis is a significant risk factor for ischemic stroke due to impaired cerebral blood flow (CBF). Even asymptomatic unilateral stenosis can induce subclinical cerebrovascular changes, potentially affecting both hemispheres through collateral circulation. This study aimed to systematically assess cerebral perfusion in asymptomatic individuals with unilateral carotid artery stenosis by comparing ipsilateral and contralateral hemispheres with healthy controls, challenging the assumption that the contralateral hemisphere remains unaffected. Materials and Methods: This cross-sectional study included 114 participants, comprising 54 asymptomatic individuals (mean age 65.5) with significant unilateral carotid stenosis and 60 age-matched controls (mean age 64.8). Cerebral perfusion was assessed using 1.5T Magnetic Resonance Imaging (MRI) with pseudo-continuous arterial spin labeling (pCASL). CBF was measured bilaterally in four predefined middle cerebral artery (MCA) regions: precentral gyrus, lentiform nucleus, insular cortex, and temporal cortex. Statistical analyses included multivariate analysis of variance (MANOVA), analysis of variance (ANOVA), paired t-tests, and discriminant analysis (DA). Results: Significant bilateral reductions in CBF were observed in individuals with carotid stenosis compared to controls (MANOVA and ANOVA, p < 0.001). The greatest perfusion deficit was in the ipsilateral insular cortex (49.88 ± 10.83 mL/100 g/min), followed by intermediate contralateral perfusion (51.49 ± 8.86 mL/100 g/min) and higher control values (58.78 ± 10.44 mL/100 g/min). DA indicated the insular cortex as the region with the highest discriminative contribution (64.7%). Conclusions: Unilateral carotid artery stenosis in asymptomatic individuals is associated with significant bilateral cerebral hypoperfusion, suggesting widespread hemodynamic effects. Pronounced perfusion deficits in the insular cortex underline its vulnerability. The observed contralateral perfusion reductions challenge the traditional use of the contralateral hemisphere as a reference standard, underscoring the need for comprehensive perfusion assessment in carotid artery disease. Full article