The novel imaging methods in diagnosis and assessment of cerebrovascular diseases: an overview.

Cerebrovascular diseases, including ischemic strokes, hemorrhagic strokes, and vascular malformations, are major causes of morbidity and mortality worldwide. The advancements in neuroimaging techniques have revolutionized the field of cerebrovascular disease diagnosis and assessment. This comprehensive review aims to provide a detailed analysis of the novel imaging methods used in the diagnosis and assessment of cerebrovascular diseases. We discuss the applications of various imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and angiography, highlighting their strengths and limitations. Furthermore, we delve into the emerging imaging techniques, including perfusion imaging, diffusion tensor imaging (DTI), and molecular imaging, exploring their potential contributions to the field. Understanding these novel imaging methods is necessary for accurate diagnosis, effective treatment planning, and monitoring the progression of cerebrovascular diseases.

A low prognostic nutritional index is associated with chronic subdural hematoma recurrence.

Chronic subdural hematoma (CSDH) is a common neurosurgical condition. Inflammation has been found to play an essential role in the formation of CSDHs, and the prognostic nutritional index (PNI), a nutritional and inflammatory baseline marker, plays a role in predicting the prognosis of many diseases. We aimed to identify the relationship between PNI and CSDH recurrence. This study retrospectively analyzed 261 CSDH patients who underwent burr hole evacuation in Beijing Tiantan Hospital from August 2013 to March 2018. The PNI was calculated as 5 ∗ lymphocyte count (109/L) + serum albumin concentration (g/L), and these markers were obtained from the peripheral blood test on the day of discharge from the hospital. Recurrence was defined as operated hematoma enlargement accompanied by newly emerging neurological disorders. The comparison of baseline characteristics demonstrated that patients with bilateral hematoma and low levels of albumin, lymphocytes, and PNI were more likely to be recurrent. After adjusting for age, sex, and other important variables, decreased PNI levels were associated with an increased risk of CSDH (OR, 0.803, 95% CI: 0.715-0.902, p = 0.001). The addition of PNI to conventional risk factors significantly improved the risk prediction of CSDH (net reclassification index: 71.12%, p = 0.001; integrated discrimination index: 10.94%, p = 0.006). A low PNI level is associated with an increased risk of CSDH recurrence. As an easily obtainable nutritional and inflammatory marker, PNI may play a significant role in predicting the recurrence of CSDH patients.

Seizure after chronic subdural hematoma evacuation: associated factors and effect on clinical outcome.

Objective: Chronic subdural hematoma (CSDH) is a common disease in neurosurgery, which usually occurs in the elderly. Seizure is one of the postoperative complications in CSDH patients and can affect patient outcomes. There is currently no consensus on whether antiepileptic drugs should be prescribed prophylactically. The aim of this study was to evaluate independent risk factors for postoperative seizures and unfavorable outcomes in CSDH patients. Methods: We reviewed 1,244 CSDH patients who had undergone burr-hole craniotomy in this study. Patient clinical data, CT scan results, recurrence and outcome data were collected. We divided the patients into two groups based on whether they had a postoperative seizure. Percentages and χ2 tests were applied for categorical variables. Standard deviations and two-sided unpaired t-tests were applied for continuous variables. Stepwise logistic regression analyses were performed to identify the independent factors of postoperative seizures and unfavorable outcomes. Results: The incidence of seizures after CSDH surgery was 4.2% in this study. There was no significant difference in recurrence rate between seizure and non-seizure patients (p = 0.948), and the outcome of seizure patients was significantly poor (p < 0.001). There are more postoperative complications in seizure patients (p < 0.001). Logistic regression analysis showed that the independent risk factors for postoperative seizures included drinking history (p = 0.031), cardiac disease (p = 0.037), brain infarction (p = 0.001) and trabecular hematoma (p < 0.001). The use of urokinase is a protective factor for postoperative seizures (p = 0.028). Hypertension is an independent risk factor for unfavorable outcome in seizure patients (p = 0.038). Conclusion: Seizures after CSDH surgery were associated with postoperative complications, higher mortality and poorer clinical outcomes at follow-up. We believe that alcohol consumption, cardiac disease, brain infarction and trabecular hematoma are independent risk factors for seizures. The use of urokinase is a protective factor against seizures. Patients with postoperative seizures need more stringent management of their blood pressure. A prospective randomized study is necessary to determine which subgroups of CSDH patients would benefit from antiepileptic drugs prophylaxis.

Optoelectronic Metasurface for Free-Space Optical-Microwave Interactions.

Photon-electron interactions are essential for many areas such as energy conversion, signal processing, and emerging quantum science. However, the current demonstrations are typically targeted to fiber and on-chip applications and lack of study in wave space. Here, we introduce a concept of optoelectronic metasurface that is capable of realizing direct and efficient optical-microwave interactions in free space. The optoelectronic metasurface is realized via a hybrid integration of microwave resonant meta-structures with a photoresponsive material. As a proof of concept, we construct an ultrathin optoelectronic metasurface using photodiodes that is bias free, which is modeled and analyzed theoretically by using the light-driven electronic excitation principle and microwave network theory. The incident laser and microwave from the free space will interact with the photodiode-based metasurface simultaneously and generate strong laser-microwave coupling, where the phase of output microwave depends on the input laser intensity. We experimentally verify that the reflected microwave phase of the optoelectronic metasurface decreases as the incident laser power becomes large, providing a distinct strategy to control the vector fields by the power intensity. Our results offer fundamentally new understanding of the metasurface capabilities and the wave-matter interactions in hybrid materials.

Poor nutritional status is associated with incomplete functional recovery in elderly patients with mild traumatic brain injury.

Background: The geriatric nutritional risk index (GNRI) is a simple index for evaluating the nutrition status of elderly patients. Many investigations have demonstrated that this index is associated with the prognosis of several diseases. This study aims to identify the relationship between the GNRI and recovery in elderly mild traumatic brain injury (mTBI) patients. Methods: A total of 228 mTBI patients older than 65 years were included in this study. mTBI was defined as an injury to the brain with a loss of consciousness of 30 min or less, a duration of posttraumatic amnesia of <24 h, and an admission Glasgow Coma Scale (GCS) score of 13-15. The Glasgow Outcome Scale Extended (GOSE), an outcome scale assessing functional independence, work, social activities, and personal relationships, was applied to assess the recovery of the patients. The clinical outcome was divided into complete recovery (GOSE = 8) and incomplete recovery (GOSE ≤ 7) at 6 months after the injury. Multivariate logistic regression was applied to evaluate the association between the GNRI and recovery of elderly mTBI patients, with adjustment for age, sex, hypertension, diabetes, and other important factors. Results: The receiver operating curve (ROC) analysis demonstrated that the cutoff value of GNRI was 97.85, and the area under the curve (AUC) was 0.860. Compared to the patients with a high GNRI, the patients with a low GNRI were older, had a higher prevalence of anemia, acute subdural hematoma, and subarachnoid hemorrhage, had a higher age-adjusted Charlson Comorbidity Index value, and had lower levels of albumin, lymphocytes, and hemoglobin. Multivariable analysis showed that high GNRI was associated with a lower risk of 6-month incomplete recovery (OR, 0.770, 95% CI: 0.709-0.837, p < 0.001). Conclusion: The GNRI has utility as part of the objective risk assessment of incomplete 6-month functional recovery in elderly patients with mTBI.

Efficacy analysis of neuroendoscopy-assisted burr-hole evacuation for chronic subdural hematoma: a systematic review and meta-analysis.

The purpose of this study was to compare neuroendoscopy-assisted burr-hole evacuation with conventional burr-hole evacuation in the treatment of chronic subdural hematoma (CSDH), and to evaluate the curative effect of neuroendoscopy. This study follows PRISMA guidelines and uses the keywords "chronic subdural hematoma," "neuroendoscopies," "neuroendoscopy," "endoscopy," "endoscopic neurosurgery," and "neuroendoscopic surgery" to conduct an electronic search of online databases, including PubMed, Embase, Web of Science, and Cochrane Library. There were no restrictions on language or publication year. This meta-analysis involved 948 patients in six studies. The results showed that the recurrence rate in the neuroendoscopy group was significantly lower than that in the conventional burr-hole group (3.1% vs. 13.8%, P<0.001). Compared with the control group, the neuroendoscopy group had a longer operation time (P<0.001) and a shorter postoperative drainage time (P<0.001). In addition, there was no significant difference in hospital stay (P=0.14), mortality (P=0.39), postoperative morbidity (P=0.12), or 6-month neurological outcomes (P=0.32) between the two groups. It should be noted that the comparison of neurological outcomes was based on 269 patients (6/106 vs. 14/163). Compared with conventional burr-hole evacuation, neuroendoscopy-assisted burr-hole evacuation reduces the recurrence rate of CSDH and shortens the postoperative drainage time. However, the neuroendoscopy group did not have lower mortality or morbidity or better functional outcomes. In the future, randomized controlled trials are needed to further evaluate the efficacy and safety of neuroendoscopic surgery.

Nutritional and inflammatory peripheral blood markers for risk assessment of chronic subdural hematoma: a case-control study.

BACKGROUND: Some peripheral blood markers have been demonstrated to be correlated with the re-formation of chronic subdural hematoma (CSDH). The aim of this study was to identify the correlation between nutritional/inflammatory peripheral blood markers and CSDH. METHODS: 188 CSDH patients and 188 age-matched healthy controls were included in this research. The clinical characteristics and peripheral blood markers associated with nutritional or inflammatory status were obtained and analyzed. Conditional logistic regression analysis was applied to identify the potential CSDH risk factors. All the participants were divided into 3 groups based on the tertiles of change in risk factors. The Cochran-Armitage test and one way ANOVA were applied to identify the association between baseline characteristics and independent risk factors. Moreover, the net reclassification index (NRI) and integrated discrimination index (IDI) were calculated to evaluate the improvement in model performance after adding the independent risk factors in the conventional model. RESULTS: The logistic regression analysis demonstrated that the increased albumin (OR, 0.615; 95 %CI,0.489-0.773; P < 0.001) and lymphocyte count (OR, 0.141; 95 %CI,0.025-0.796; P = 0.027) were associated with lower risk of CSDH. Moreover, addition of albumin and lymphocyte to conventional risk factors significantly improved the risk prediction of CSDH(NRI: 46.47 %, P < 0.001; IDI: 30.92 %, P < 0.001; NRI: 22.45 %, P = 0.027; IDI: 1.23 %, P = 0.037, respectively) CONCLUSION: The decreased albumin and lymphocyte levels were correlated with a high risk of chronic subdural hematoma. The nutritional and inflammatory serum markers should be put great attention because these markers may play roles in finding the cause of CSDH and predicting its risk.

Exhaustive drainage versus fixed-time drainage for chronic subdural hematoma after one-burr hole craniostomy (ECHO): study protocol for a multicenter randomized controlled trial.

BACKGROUND: Chronic subdural hematomas (CSDHs) are one of the most common neurosurgical conditions. The standard surgical technique includes burr-hole craniostomy, followed by intraoperative irrigation and placement of subdural closed-system drainage. The drainage is generally removed after 48 h, which can be described as fixed-time drainage strategy. According to literature, the recurrence rate is 5-33% with this strategy. In our retrospective study, postoperative hematoma volume was found to significantly increase the risk of recurrence. Based on these results, an exhaustive drainage strategy is conducted to minimize postoperative hematoma volume and achieve a low recurrence rate and good outcomes. METHODS: This is a prospective, multicenter, open-label, blinded endpoint randomized controlled trial designed to include 304 participants over the age of 18-90 years presenting with a symptomatic CSDH verified on cranial computed tomography or magnetic resonance imaging. Participants will be randomly allocated to perform exhaustive drainage (treatment group) or fixed-time drainage (control group) after a one-burr hole craniostomy. The primary endpoint will be recurrence indicating a reoperation within 6 months. DISCUSSION: This study will validate the effect and safety of exhaustive drainage after one-burr hole craniostomy in reducing recurrence rates and provide critical information to improve CSDH surgical management. TRIAL REGISTRATION: Clinicaltrials.gov, NCT04573387. Registered on October 5, 2020.

Postoperative pneumocephalus and recurrence and outcome of chronic subdural hematoma: a systematic review and meta-analysis.

We conducted a meta-analysis to analyze the effects of pneumocephalus after chronic subdural hematoma (CSDH) surgery on hematoma recurrence, mortality, and functional outcomes. In this meta-analysis, following PRISMA guidelines, PubMed, Embase, Cochrane Library, and Web of Science online databases were queried using the keywords "pneumocephalus," "pneumoencephalos," "intracranial pneumatocele," "pneumo encephalon," "subdural air," and "chronic subdural hematoma." The results were limited to English-language articles. Through the online database, we identified a total of 276 articles and finally included 14 articles for meta-analysis. The results showed that the recurrence rate in the pneumocephalus group was higher than that in the control group, with a pooled OR of 3.35 (CI: 2.51-4.46, P < 0.001). There was no difference in recurrence rate between the no/few and moderate pneumocephalus groups (OR: 1.27, CI: 0.68-2.37, P = 0.46), but the recurrence rate of the large pneumocephalus group was significantly higher than that of the moderate group, with a pooled OR of 3.29 (CI: 1.71-6.32, P < 0.001). This study failed to show higher mortality and worse outcomes in the pneumocephalus group than in the control. Pneumocephalus after surgical evacuation of CSDH was associated with the recurrence rate of hematoma. Pneumocephalus affecting recurrence was correlated with gas volume, and moderate pneumocephalus may have less impact, while patients with large pneumocephalus are more likely to recur than those with moderate pneumocephalus. More prospective cohort studies are needed for further investigation and verification. This meta-analysis was registered (PROSPERO CRD42022321800).

A metasurface-based light-to-microwave transmitter for hybrid wireless communications.

Signal conversion plays an important role in many applications such as communication, sensing, and imaging. Realizing signal conversion between optical and microwave frequencies is a crucial step to construct hybrid communication systems that combine both optical and microwave wireless technologies to achieve better features, which are highly desirable in the future wireless communications. However, such a signal conversion process typically requires a complicated relay to perform multiple operations, which will consume additional hardware/time/energy resources. Here, we report a light-to-microwave transmitter based on the time-varying and programmable metasurface integrated with a high-speed photoelectric detection circuit into a hybrid. Such a transmitter can convert a light intensity signal to two microwave binary frequency shift keying signals by using the dispersion characteristics of the metasurface to implement the frequency division multiplexing. To illustrate the metasurface-based transmitter, a hybrid wireless communication system that allows dual-channel data transmissions in a light-to-microwave link is demonstrated, and the experimental results show that two different videos can be transmitted and received simultaneously and independently. Our metasurface-enabled signal conversion solution may enrich the functionalities of metasurfaces, and could also stimulate new information-oriented applications.

Spatial full-duplex light communication achieved with a monolithic non-suspended multicomponent system.

The multiple-quantum-well diode (MQW-diode) inherently exhibits simultaneous behavior because of the overlap between the emission spectra and spectral responsivity of the MQW-diode. This feature makes it feasible to form a full-duplex light communication system when two identical MQW-diodes separately function as a transmitter and a receiver at the same time. To verify spatial full-duplex light communication, we fabricated and characterized a monolithic multicomponent system by integrating two InGaN waveguide-based MQW-diodes into a single chip. A 5-µm-wide air gap between two MQW-diodes was manufactured for precise alignment, which could yield spatial light transmission and coupling. Spatial co-time co-frequency full-duplex (CCFD) light communication was experimentally demonstrated using the monolithic multicomponent system, a self-interference cancellation scheme was used to extract the superimposed signals, and a full-duplex audio transmission experiment was performed, opening a promising route toward parallel information processing via free space based on the simultaneous light-emitting and light-detecting phenomenon of the MQW-diode.

Full-duplex light communication with a monolithic multicomponent system.

A monolithic multicomponent system is proposed and implemented on a III-nitride-on-silicon platform, whereby two multiple-quantum-well diodes (MQW-diodes) are interconnected by a suspended waveguide. Both MQW-diodes have an identical low-In-content InGaN/Al0.10Ga0.90N MQW structure and are produced by the same fabrication process flow. When appropriately biased, both MQW-diodes operate under a simultaneous emission-detection mode and function as a transmitter and a receiver at the same time, forming an in-plane full-duplex light communication system. Real-time full-duplex audio communication is experimentally demonstrated using the monolithic multicomponent system in combination with an external circuit.

Tandem dual-functioning multiple-quantum-well diodes for a self-powered light source.

Nitride-based semiconductor materials inherently have the intriguing functionalities of emission and photodetection. In particular, InGaN/GaN multiple-quantum-well (MQW) diodes exhibit dual light-harvesting and light-emitting modes of operation. Here a multifunctional system is proposed to integrate MQW diodes within a single chip with enhanced functionalities toward diverse applications of the Internet of Things (IoT). When we shine light on the MQW diodes, the absorbed photons can produce electron-hole pairs to charge an external capacitor. The energy of the ambient light is converted into electrical energy, which in turn powers the same MQW diode for lighting. The electrical energy within the capacitor is finally converted into the energy of the emitted light. Therefore, InGaN/GaN MQW diodes can be made to harvest energy from ambient light sources for IoT applications from a self-powered light source to intelligent terminal charging system.

Spatiotemporal summation and correlation mimicked in a four-emitter light-induced artificial synapse.

In the brain, each postsynaptic neuron interconnects many presynaptic neurons and performs functions that are related to summation and recognition as well as correlation. Based on a convolution operation and nonlinear distortion function, we propose a mathematical model to explore the elementary synaptic mechanism. A four-emitter light-induced artificial synapse is implemented on an III-nitride-on-silicon platform to validate the device concept for emulating the synaptic behaviors of a biological synapse with multiple presynaptic inputs. In addition to a progressive increase in the amplitude of successive spatiotemporal excitatory postsynaptic voltages, the differences in the stimulations are remembered for signal recognition. When repetitive stimulations are simultaneously applied and last over a long period of time, resonant spatiotemporal correlation occurs because an association is formed between the presynaptic stimulations. Four resonant spatiotemporal correlations of each triple-stimulation combination are experimentally demonstrated and agree well with the simulation results. The repetitive stimulation combinations with prime number-based periods inherently exhibit the maximum capacity of resonant spatiotemporal correlation. Our work offers a new approach to building artificial synapse networks.