Topology Regulated Background Extraction (TRBE) method for eye fundus images.

One of the initial steps in the preprocessing of digital fundoscopy images is the identification of pixels containing relevant information. This can be achieved through different approaches, one of them is implementing background extraction, reducing the set of pixels to be analyzed later in the process. In this work, we present a background extraction method for digital fundoscopy images based on computational topology. By interpreting binarized images as cubical complexes and extracting their homological groups in 1 and 2 dimensions we identify a subset of luminescence values that can be used to binarize the original grayscale image, obtaining a mask to achieve background extraction. This method is robust to noise and suboptimal image quality, facilitating the analytical pipeline in the context of computer aided diagnosis approaches. This method facilitates the segmentation of the background of a digital fundoscopy image, which allows further methods to focus on pixels with relevant information (eye fundus). This tool is best suited to be implemented in the preprocessing stages of the analytical pipeline by computational ophthalmology specialists.•It is robust to noise and low-quality images.•Output provides an ideal scenario for down-the-line analysis by facilitating only relevant pixels in a digital fundoscopy.

Impact of Early Blood Pressure Lowering in Patients Presenting with Acute Ischemic Stroke.

PURPOSE OF REVIEW: In this review article we will discuss the acute hypertensive response in the context of acute ischemic stroke and present the latest evidence-based concepts of the significance and management of the hemodynamic response in acute ischemic stroke. RECENT FINDINGS: Acute hypertensive response is considered a common hemodynamic physiologic response in the early setting of an acute ischemic stroke. The significance of the acute hypertensive response is not entirely well understood. However, in certain types of acute ischemic strokes, the systemic elevation of the blood pressure helps to maintain the collateral blood flow in the penumbral ischemic tissue. The magnitude of the elevation of the systemic blood pressure that contributes to the maintenance of the collateral flow is not well established. The overcorrection of this physiologic hemodynamic response before an effective vessel recanalization takes place can carry a negative impact in the final clinical outcome. The significance of the persistence of the acute hypertensive response after an effective vessel recanalization is poorly understood, and it may negatively affect the final outcome due to reperfusion injury. Acute hypertensive response is considered a common hemodynamic reaction of the cardiovascular system in the context of an acute ischemic stroke. The reaction is particularly common in acute brain embolic occlusion of large intracranial vessels. Its early management before, during, and immediately after arterial reperfusion has a repercussion in the final fate of the ischemic tissue and the clinical outcome.

Transradial Access Results in Faster Skin Puncture to Reperfusion Time than Transfemoral Access in Posterior Circulation Mechanical Thrombectomy.

BACKGROUND: Successful mechanical embolectomy for acute embolic arterial occlusion in the posterior cerebral circulation can potentially result in less neurologic disability and mortality. The transradial approach can potentially offer more direct navigation into the posterior circulation than the transfemoral approach and can result in faster recanalization time. OBJECTIVE: To compare procedural metrics and the technical and clinical outcomes of transradial versus transfemoral access for mechanical embolectomy in the posterior cerebral circulation. MATERIAL AND METHODS: Single-center retrospective review of a prospectively maintained neurointerventional database from a large volume neurointerventional service in a tertiary academic center. Patients presenting with acute disabling symptoms due to embolic occlusion of a large intracranial artery in the posterior that underwent to endovascular treatment in our institution from January 2017 to January 2019 were included in the present study. RESULTS: Between January 2018 and January 2019 a total of 10 subjects underwent a mechanical embolectomy for acute embolic occlusion on the posterior circulation via transradial access; and between January 2017 and January 2018 a total of 10 subjects underwent a mechanical embolectomy for acute embolic occlusion on the posterior circulation via transfemoral access. Subjects in the transradial access group had a shorter skin puncture to recanalization time compared to the transfemoral group (29.2 ± 17.6 in the transradial group vs. 63.9 ± 56.7 in the transfemoral group respectively). CONCLUSIONS: This is the first study comparing transradial versus transfemoral access for mechanical embolectomy in patients with acute embolic occlusion in the posterior cerebral circulation. Transradial access resulted in a safe, effective, and faster endovascular route for recanalization in the acute embolic occlusion of the posterior circulation.

Ketamine for rapid reduction of suicidal ideation: a randomized controlled trial.

BACKGROUND: Suicide is a devastating public health problem and very few biological treatments have been found to be effective for quickly reducing the intensity of suicidal ideation (SI). We have previously shown that a single dose of ketamine, a glutamate N-methyl-d-aspartate (NMDA) receptor antagonist, is associated with a rapid reduction in depressive symptom severity and SI in patients with treatment-resistant depression. METHOD: We conducted a randomized, controlled trial of ketamine in patients with mood and anxiety spectrum disorders who presented with clinically significant SI (n = 24). Patients received a single infusion of ketamine or midazolam (as an active placebo) in addition to standard of care. SI measured using the Beck Scale for Suicidal Ideation (BSI) 24 h post-treatment represented the primary outcome. Secondary outcomes included the Montgomery-Asberg Depression Rating Scale--Suicidal Ideation (MADRS-SI) score at 24 h and additional measures beyond the 24-h time-point. RESULTS: The intervention was well tolerated and no dropouts occurred during the primary 7-day assessment period. BSI score was not different between the treatment groups at 24 h (p = 0.32); however, a significant difference emerged at 48 h (p = 0.047). MADRS-SI score was lower in the ketamine group compared to midazolam group at 24 h (p = 0.05). The treatment effect was no longer significant at the end of the 7-day assessment period. CONCLUSIONS: The current findings provide initial support for the safety and tolerability of ketamine as an intervention for SI in patients who are at elevated risk for suicidal behavior. Larger, well-powered studies are warranted.

Rate and prognosis of patients under conscious sedation requiring emergent intubation during neuroendovascular procedures.

BACKGROUND AND PURPOSE: Neuroendovascular procedures are performed with the patient under conscious sedation (local anesthesia) in varying numbers of patients in different institutions, though the risk of unplanned conversion to general anesthesia is poorly characterized. Our aim was to ascertain the rate of failure of conscious sedation in patients undergoing neuroendovascular procedures and compare the in-hospital outcomes of patients who were converted from conscious sedation to general anesthesia with those whose procedures were initiated with general anesthesia. MATERIALS AND METHODS: All patients who had an endovascular procedure initiated under general anesthesia or conscious sedation were identified through a prospective data base maintained at 2 comprehensive stroke centers. Patient clinical and procedural characteristics, in-hospital deaths, and favorable outcomes (modified Rankin Scale score, 0-2) at discharge were ascertained. RESULTS: Nine hundred seven endovascular procedures were identified, of which 387 were performed with the patient under general anesthesia, while 520 procedures were initiated with conscious sedation. Among procedures initiated with intent to be performed under conscious sedation, 9 (1.7%) procedures required emergent conversion to general anesthesia. Favorable clinical outcome and in-hospital mortality in patients requiring emergent conversion from conscious sedation to general anesthesia and in those with procedures initiated with general anesthesia were not statistically different (42% versus 50%, P = .73 and 17% versus 13%, P = 1.00, respectively). CONCLUSIONS: In our study, there was a very low rate of conscious sedation failure and associated adverse outcomes among patients undergoing neuroendovascular procedures. Proper patient selection is important if procedures are to be performed with the patient under conscious sedation. Limitations of the methodology used in our study preclude us from offering specific recommendations regarding when to use a specific anesthetic protocol.

Requirements for emergent neurosurgical procedures among patients undergoing neuroendovascular procedures in contemporary practice.

BACKGROUND AND PURPOSE: Provisions for an emergent neurosurgical procedure have been a mandatory component of centers that perform neuroendovascular procedures. We sought to determine the need for emergent neurosurgical procedures following neuroendovascular interventions in 2 comprehensive stroke centers in settings with such provisions. MATERIALS AND METHODS: Analysis of retrospectively collected data from procedure logs and patient charts was performed to identify patients who required immediate (before the termination of the intervention) or adjunctive (within 24 hours of the intervention) neurosurgical procedures related to a neuroendovascular intervention complication. The types of neurosurgical procedures and in-hospital outcomes of identified patients are reported as an aggregate and per endovascular procedure-type analyses. RESULTS: We reviewed a total of 933 neuroendovascular procedures performed during 3.5 years (2006-2010). A total of 759 intracranial procedures were performed. There was a need for emergent neurosurgical procedures in 8 patients (0.85% cumulative incidence and 1.05% for major intracranial procedures) (mean age, 46 years; 7 were women); the procedures were categorized as 3 immediate and 5 adjunctive procedures. There were 5 in-hospital deaths (62.5%) among these 8 patients. Neurosurgical procedures performed were external ventricular drainage placement in 6 (6 of 8, 75%) patients, decompressive craniectomy in 1 (12.5%) patient, and both surgical procedures in 1 (12.5%) patient. CONCLUSIONS: The need for emergent neurosurgical procedures is very low among patients undergoing intracranial neuroendovascular procedures. Survival in such patients despite emergent neurosurgical procedures is quite low.

Endovascular interventions following intravenous thrombolysis may improve survival and recovery in patients with acute ischemic stroke: a case-control study.

BACKGROUND AND PURPOSE: Since the introduction of recombinant tissue plasminogen activator (rtPA) into clinical practice in the mid 1990s, no adjunctive treatment has further improved clinical outcomes in patients with ischemic stroke. The safety, feasibility, and efficacy of combining intravenous (IV) rtPA with endovascular interventions has been described; however, no direct comparative study has yet established whether endovascular interventions after IV rtPA are superior to IV rtPA alone. A retrospective case-control study was designed to address this issue. MATERIALS AND METHODS: Between 2003 and 2006, 33 consecutive patients with acute ischemic stroke and National Institutes of Health Stroke Scale (NIHSS) scores >/=10 were treated with IV rtPA in combination with endovascular interventions (IV plus intervention) at a tertiary care facility. Outcomes were compared with a control cohort of 30 consecutive patients treated with IV rtPA (IV only) at a comparable facility where endovascular interventions were not available. RESULTS: Baseline parameters were similar between the 2 groups. We found that the IV-plus-intervention group experienced significantly lower mortality at 90 days (12.1% versus 40.0%, P = .019) with a significantly greater improvement in NIHSS scores by the time of discharge or follow-up (P = .025). In the IV-plus-intervention group, patients with admission NIHSS scores between 10 and 15 and patients /=10, there was a suggestion of incremental clinical benefit among patients receiving endovascular interventions following standard administration of IV rtPA.

Distinct recognition of substrates by the human and Drosophila serotonin transporters.

The human and Drosophila serotonin transporters (hSERT and dSERT, respectively) were used to explore differences in substrate properties. hSERT and dSERT showed similar Km values for 5-hydroxytryptamine (5-HT; serotonin) transport (1.2 and 0.9 micro M, respectively), suggesting similar recognition of 5-HT by the two species variants. Although dSERT cell surface expression was approximately 8-fold lower than that of hSERT, dSERT does appear to have a 2-fold faster turnover number for inward transport of 5-HT. Interestingly, another substrate, N-methyl-4-phenylpyridinium (MPP+), was transported only by hSERT. However, MPP+ inhibited 5-HT uptake in both species variants with similar potencies. Two cross-species chimeras, H1-118D119-627 and H1-281D282-476H477-638, were also unable to transport MPP+, implicating the role of transmembrane domains V to IX in the substrate permeation pathway. Based on exchange experiments, certain substituted-amphetamines also appear to be poor substrates at dSERT. Two-electrode voltage-clamp studies in oocytes confirmed that the amphetamines do not possess substrate-like properties for dSERT. Our data suggest distinct molecular recognition among SERT substrate classes that influence translocation mechanisms.