ABSTRACT
OBJECTIVES: Evaluate if nonoperative or operative treatment of displaced clavicle fractures delivers reduced rates of nonunion and improved Disability of the Arm, Shoulder, and Hand (DASH) scores. DESIGN: Multicenter, prospective, observational. SETTING: Seven Level 1 Trauma Centers in the United States. PATIENT SELECTION CRITERIA: Adults with closed, displaced (100% displacement/shortened >1.5 cm) midshaft clavicle fractures (Orthopaedic Trauma Association 15.2) were treated nonoperatively, with plates and screw fixation, or with intramedullary fixation from 2003 to 2018. OUTCOME MEASURES AND COMPARISONS: DASH scores (2, 6 weeks, 3, 6, 12, and 24 months), reoperation, and nonunion were compared between the nonoperative, plate fixation, and intramedullary fixation groups. RESULTS: Four hundred twelve patients were enrolled, with 203 undergoing plate fixation, 26 receiving intramedullary fixation, and 183 treated nonoperatively. The average age of the nonoperative group was 40.1 (range 18-79) years versus 35.8 (range 18-74) in the plate group and 39.3 (range 19-56) in the intramedullary fixation group (P = 0.06). One hundred forty (76.5%) patients in the nonoperative group were male compared with 154 (75.9%) in the plate group and 18 (69.2%) in the intramedullary fixation group (P = 0.69). All groups showed similar DASH scores at 2 weeks, 12 months, and 24 months (P > 0.05). Plate fixation demonstrated better DASH scores (median = 20.8) than nonoperative (median = 28.3) at 6 weeks (P = 0.04). Intramedullary fixation had poorer DASH scores at 6 weeks, 3 months, and 6 months than plate fixation and worse DASH scores than nonoperative at 6 months (P < 0.05). The nonunion rate for nonoperative treatment (14.6%) was significantly higher than the plate group (0%) (P < 0.001). CONCLUSIONS: Operative treatment of displaced clavicle fractures provided lower rates of nonunion than nonoperative treatment. Except at 6 weeks, no difference was observed in DASH scores between plate fixation and nonoperative treatment. Intramedullary fixation resulted in worse DASH scores than plate fixation at 6 weeks, 3 months, and 6 months and worse DASH scores than nonoperative at 6 months. Implant removal was the leading reason for reoperation in the plate and intramedullary fixation groups, whereas surgery for nonunion was the primary reason for surgery in the nonoperative group. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.
Subject(s)
Bone Plates , Clavicle , Fracture Fixation, Intramedullary , Fractures, Bone , Humans , Clavicle/injuries , Clavicle/surgery , Adult , Prospective Studies , Middle Aged , Male , Female , Fractures, Bone/surgery , Aged , Fracture Fixation, Intramedullary/methods , Young Adult , Adolescent , Treatment Outcome , Bone Screws , Fracture Fixation, Internal/methodsABSTRACT
Significance: Positive margin status due to incomplete removal of tumor tissue during radical prostatectomy for high-risk localized prostate cancer requires reoperation or adjuvant therapy, which increases morbidity and mortality. Adverse effects of prostate cancer treatments commonly include erectile dysfunction, urinary incontinence, and bowel dysfunction, making successful initial curative prostatectomy imperative. Aim: Current intraoperative tumor margin assessment is largely limited to frozen section analysis, which is a lengthy, labor-intensive process that is obtrusive to the clinical workflow within the operating room (OR). Therefore, a rapid method for prostate cancer margin assessment in the OR could improve outcomes for patients. Approach: Dual probe difference specimen imaging (DDSI), which uses paired antibody-based probes that are labeled with spectrally distinct fluorophores, was shown herein for prostate cancer margin assessment. The paired antibody-based probes consisted of a targeted probe to prostate-specific membrane antigen (PSMA) and an untargeted probe, which were used as a cocktail to stain resected murine tissue specimens including prostate tumor, adipose, muscle, and normal prostate. Ratiometric images (i.e., DDSI) of the difference between targeted and untargeted probe uptake were calculated and evaluated for accuracy using receiver operator characteristic curve analysis with area under the curve values used to evaluate the utility of the DDSI method to detect PSMA positive prostate cancer. Results: Targeted and untargeted probe uptake was similar between the high and low PSMA expressing tumor due to nonspecific probe uptake after topical administration. The ratiometric DDSI approach showed substantial contrast difference between the PSMA positive tumors and their respective normal tissues (prostate, adipose, muscle). Furthermore, DDSI showed substantial contrast difference between the high PSMA expressing tumors and the minimally PSMA expressing tumors due to the ratiometric correction for the nonspecific uptake patterns in resected tissues. Conclusions: Previous work has shown that ratiometic imaging has strong predictive value for breast cancer margin status using topical administration. Translation of the ratiometric DDSI methodology herein from breast to prostate cancers demonstrates it as a robust, ratiometric technique that provides a molecularly specific imaging modality for intraoperative margin detection. Using the validated DDSI protocol on resected prostate cancers permitted rapid and accurate assessment of PSMA status as a surrogate for prostate cancer margin status. Future studies will further evaluate the utility of this technology to quantitatively characterize prostate margin status using PSMA as a biomarker.
Subject(s)
Prostatic Neoplasms , Humans , Male , Diagnostic Imaging , Prostate/diagnostic imaging , Prostate/surgery , Prostate/pathology , Prostatectomy , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/surgeryABSTRACT
OBJECTIVE: To examine potential genetic relationships between migraine and the two distinct phenotypes posterior circulation ischemic stroke (PCiS) and anterior circulation ischemic stroke (ACiS), we generated migraine polygenic risk scores (PRSs) and compared these between PCiS and ACiS, and separately vs. non-stroke control subjects. METHODS: Acute ischemic stroke cases were classified as PCiS or ACiS based on lesion location on diffusion-weighted MRI. Exclusion criteria were lesions in both vascular territories or uncertain territory; supratentorial PCiS with ipsilateral fetal posterior cerebral artery; and cases with atrial fibrillation. We generated migraine PRS for three migraine phenotypes (any migraine; migraine without aura; migraine with aura) using publicly available GWAS data and compared mean PRSs separately for PCiS and ACiS vs. non-stroke control subjects, and between each stroke phenotype. RESULTS: Our primary analyses included 464 PCiS and 1079 ACiS patients with genetic European ancestry. Compared to non-stroke control subjects (n=15396), PRSs of any migraine were associated with increased risk of PCiS (p=0.01-0.03) and decreased risk of ACiS (p=0.010-0.039). Migraine without aura PRSs were significantly associated with PCiS (p=0.008-0.028), but not with ACiS. When comparing PCiS vs. ACiS directly, migraine PRSs were higher in PCiS vs. ACiS for any migraine (p=0.001-0.010) and migraine without aura (p=0.032-0.048). Migraine with aura PRS did not show a differential association in our analyses. CONCLUSIONS: Our results suggest a stronger genetic overlap between unspecified migraine and migraine without aura with PCiS compared to ACiS. Possible shared mechanisms include dysregulation of cerebral vessel endothelial function.
Subject(s)
Ischemic Stroke , Migraine with Aura , Migraine without Aura , Diffusion Magnetic Resonance Imaging , Humans , Migraine with Aura/diagnostic imaging , Migraine with Aura/genetics , Migraine without Aura/diagnostic imaging , Migraine without Aura/genetics , Risk FactorsABSTRACT
Adults who are homeless experience poor health and frequently require hospital in-patient care but the physical functioning ability of this group is rarely considered. The objective of this study was to evaluate a broad range of physical functioning variables to enable better future planning of targeted health and accommodation services for this group. This cross-sectional, observational study was conducted in a large acute hospital in Dublin, Ireland. A comprehensive ward-based test battery evaluated physical functioning in 65 in-patients registered as homeless with an age range of 23-80 years. Less than 10% (n = 5) were > 70 years. 58/65 (83%) of participants had mobility limitations and 35/65 (54%) reported at least one fall in the previous six months. Only 25/66 (35%) were able to walk for 6 min and 20/65 (31%) were able to climb one flight of stairs. 45/63 (70%) of participants were pre-frail or frail. Muscular mass was normal in the majority of participants but grip strength was low. This study revealed hospital in-patients registered as homeless displayed particularly poor physical functioning levels and mobility regardless of age. Health and housing services should address the unmet physical functioning needs of this vulnerable group.
Subject(s)
Hospitalization/statistics & numerical data , Ill-Housed Persons , Physical Functional Performance , Self Report/statistics & numerical data , Vulnerable Populations/statistics & numerical data , Accidental Falls/statistics & numerical data , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Exercise Test/statistics & numerical data , Female , Humans , Ireland , Male , Middle Aged , Young AdultABSTRACT
BACKGROUND: Re-excision rates following breast conserving surgery (BCS) remain as high as ~ 35%, with positive margins detected during follow-up histopathology. Additional breast cancer resection surgery is not only taxing on the patient and health care system, but also delays adjuvant therapies, increasing morbidity and reducing the likelihood of a positive outcome. The ability to precisely resect and visualize tumor margins in real time within the surgical theater would greatly benefit patients, surgeons and the health care system. Current tumor margin assessment technologies utilized during BCS involve relatively lengthy and labor-intensive protocols, which impede the surgical work flow. METHODS: In previous work, we have developed and validated a fluorescence imaging method termed dual probe difference specimen imaging (DDSI) to accurately detect benign and malignant tissue with direct correlation to the targeted biomarker expression levels intraoperatively. The DDSI method is currently on par with touch prep cytology in execution time (~ 15-min). In this study, the main goal was to shorten the DDSI protocol by decreasing tissue blocking and washing times to optimize the DDSI protocol to < 10-min whilst maintaining robust benign and malignant tissue differentiation. RESULTS: We evaluated the utility of the shortened DDSI staining methodology using xenografts grown from cell lines with varied epidermal growth factor receptor (EGFR) expression levels, comparing accuracy through receiver operator characteristic (ROC) curve analyses across varied tissue blocking and washing times. An optimized 8-min DDSI methodology was developed for future clinical translation. CONCLUSIONS: Successful completion of this work resulted in substantial shortening of the DDSI methodology for use in the operating room, that provided robust, highly receptor specific, sensitive diagnostic capabilities between benign and malignant tissues.
Subject(s)
Breast Neoplasms/diagnostic imaging , Breast Neoplasms/pathology , Diagnostic Imaging/methods , Molecular Probes , Animals , Breast Neoplasms/surgery , Cell Line, Tumor , Disease Models, Animal , Female , Humans , Mice , Neoplasm Staging , Staining and Labeling/methodsABSTRACT
INTRODUCTION: Thyroid radiation shields are often uncovered by the surgical gown and may represent a preventable source of wound contamination. The aims of this study are to define the common pathogens found on thyroid radiation shields and evaluate the effectiveness of a simple cleaning method. METHODS: Samples were obtained from 29 community thyroid shields collected from the operating theatres of 3 teaching hospitals. Each shield was swabbed under strict sterile technique using a separate swab for each of 4 designated zones. After sampling, shields were cleaned with a readily available disinfectant and sampling was repeated after 5 min. All swabs were cultured in ambient air at 37 °C on 5% sheeps blood agar for 48 hrs and subsequent growth was identified by a MALDI-TOF Walkaway mass spectrometer. RESULTS: Before cleaning, 100% of thyroid shields (29/29) and 68% of shield zones (79/116) grew at least 1 type of bacteria. Coagulase negative staphylococci, including S. epidermidis, S. capitis, S. cohnii, S. haemolyticus and S. hominis, were most commonly isolated. Enterobacteriaceae and S. aureus were also cultured. After cleaning, culturable contamination was reduced by 86.3% and 64.5%, respectively (p < 0.001). CONCLUSION: The most common pathogens associated with SSIs can be isolated on thyroid radiation shields. Appropriate cleaning of thyroid shields with readily available disinfectant can significantly reduce the bacterial burden as detectable by culture. Hospitals should facilitate staff education and reinforce their policies on cleaning these shields which may often be overlooked.
ABSTRACT
Nerve-binding fluorophores with near-infrared (NIR; 650 to 900 nm) emission could reduce iatrogenic nerve injury rates by providing surgeons precise, real-time visualization of the peripheral nervous system. Unfortunately, current systemically administered nerve contrast agents predominantly emit at visible wavelengths and show nonspecific uptake in surrounding tissues such as adipose, muscle, and facia, thus limiting detection to surgically exposed surface-level nerves. Here, a focused NIR fluorophore library was synthesized and screened through multi-tiered optical and pharmacological assays to identify nerve-binding fluorophore candidates for clinical translation. NIR nerve probes enabled micrometer-scale nerve visualization at the greatest reported tissue depths (~2 to 3 mm), a feat unachievable with previous visibly emissive contrast agents. Laparoscopic fluorescent surgical navigation delineated deep lumbar and iliac nerves in swine, most of which were invisible in conventional white-light endoscopy. Critically, NIR oxazines generated contrast against all key surgical tissue classes (muscle, adipose, vasculature, and fascia) with nerve signal-to-background ratios ranging from ~2 (2- to 3-mm depth) to 25 (exposed nerve). Clinical translation of NIR nerve-specific agents will substantially reduce comorbidities associated with surgical nerve damage.
Subject(s)
Nerve Tissue , Spectroscopy, Near-Infrared , Animals , Fluorescent Dyes , Optical Imaging , SwineABSTRACT
One of the most feared complications after arthroplasty is infection due to its significant impact on patient morbidity. Infection may transfer to the joint at the time of surgery or be seeded, haematologically, to the prosthetic joint from another infection source. In this case, a 72-year-old female presented with symptoms of septic arthritis seven years after her original arthroplasty surgery. At presentation, she denied trauma and any comorbidity which would predispose her to infection. Culturing of samples taken revealed the patient was infected with Neisseria meningitidis, and the patient underwent a DAIR procedure. She continued postoperative long-term antimicrobial therapy with resolution of her infection. Follow-up at one year showed complete resolution of the patient's illness with a return to premorbid baseline. To our knowledge, this is the third reported case of septic arthritis caused by Neisseria meningitidis in a prosthetic joint in the literature.
ABSTRACT
OBJECTIVE: Posterior circulation ischemic stroke (PCiS) constitutes 20-30% of ischemic stroke cases. Detailed information about differences between PCiS and anterior circulation ischemic stroke (ACiS) remains scarce. Such information might guide clinical decision making and prevention strategies. We studied risk factors and ischemic stroke subtypes in PCiS vs. ACiS and lesion location on magnetic resonance imaging (MRI) in PCiS. METHODS: Out of 3,301 MRIs from 12 sites in the National Institute of Neurological Disorders and Stroke (NINDS) Stroke Genetics Network (SiGN), we included 2,381 cases with acute DWI lesions. The definition of ACiS or PCiS was based on lesion location. We compared the groups using Chi-squared and logistic regression. RESULTS: PCiS occurred in 718 (30%) patients and ACiS in 1663 (70%). Diabetes and male sex were more common in PCiS vs. ACiS (diabetes 27% vs. 23%, p < 0.05; male sex 68% vs. 58%, p < 0.001). Both were independently associated with PCiS (diabetes, OR = 1.29; 95% CI 1.04-1.61; male sex, OR = 1.46; 95% CI 1.21-1.78). ACiS more commonly had large artery atherosclerosis (25% vs. 20%, p < 0.01) and cardioembolic mechanisms (17% vs. 11%, p < 0.001) compared to PCiS. Small artery occlusion was more common in PCiS vs. ACiS (20% vs. 14%, p < 0.001). Small artery occlusion accounted for 47% of solitary brainstem infarctions. CONCLUSION: Ischemic stroke subtypes differ between the two phenotypes. Diabetes and male sex have a stronger association with PCiS than ACiS. Definitive MRI-based PCiS diagnosis aids etiological investigation and contributes additional insights into specific risk factors and mechanisms of injury in PCiS.
Subject(s)
Cerebral Arterial Diseases/complications , Stroke/diagnostic imaging , Stroke/etiology , Vertebrobasilar Insufficiency/complications , Aged , Arterial Occlusive Diseases/complications , Basilar Artery/pathology , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Neuroimaging , Phenotype , Stroke/pathology , Vertebral Artery/pathologyABSTRACT
Lightning is a dangerous yet poorly understood natural phenomenon. Lightning forms a network of plasma channels propagating away from the initiation point with both positively and negatively charged ends-called positive and negative leaders1. Negative leaders propagate in discrete steps, emitting copious radio pulses in the 30-300-megahertz frequency band2-8 that can be remotely sensed and imaged with high spatial and temporal resolution9-11. Positive leaders propagate more continuously and thus emit very little high-frequency radiation12. Radio emission from positive leaders has nevertheless been mapped13-15, and exhibits a pattern that is different from that of negative leaders11-13,16,17. Furthermore, it has been inferred that positive leaders can become transiently disconnected from negative leaders9,12,16,18-20, which may lead to current pulses that both reconnect positive leaders to negative leaders11,16,17,20-22 and cause multiple cloud-to-ground lightning events1. The disconnection process is thought to be due to negative differential resistance18, but this does not explain why the disconnections form primarily on positive leaders22, or why the current in cloud-to-ground lightning never goes to zero23. Indeed, it is still not understood how positive leaders emit radio-frequency radiation or why they behave differently from negative leaders. Here we report three-dimensional radio interferometric observations of lightning over the Netherlands with unprecedented spatiotemporal resolution. We find small plasma structures-which we call 'needles'-that are the dominant source of radio emission from the positive leaders. These structures appear to drain charge from the leader, and are probably the reason why positive leaders disconnect from negative ones, and why cloud-to-ground lightning connects to the ground multiple times.
ABSTRACT
Identification of tumor margins in the operating room in real time is a critical challenge for surgical procedures that serve as cancer cure. Breast conserving surgery (BCS) is particularly affected by this problem, with current re-excision rates above 25%. Due to a lack of clinically available methodologies for detection of involved or close tumor margins, much effort is focused on developing intraoperative margin assessment modalities that can aid in addressing this unmet clinical need. BCS provides a unique opportunity to design contrast-based technologies that are able to assess tumor margins independent from the patient, providing a rapid pathway from bench to bedside at a much lower cost. Since resected tissue is removed from the patient's blood supply, non-specific contrast agent uptake becomes a challenge due to the lack of clearance. Therefore, a dual probe, ratiometric fluorescence imaging approach was taken in an effort to reduce non-specific signal, and provide a modality that could demonstrate rapid, robust margin assessment on resected patient samples. Termed, dual-stain difference specimen imaging (DDSI), DDSI includes the use of spectrally unique, and fluorescently labeled target-specific, as well as non-specific biomarkers. In the present study, we have applied epidermal growth factor receptor (EGFR) targeted DDSI to tumor xenografts with variable EGFR expression levels using a previously optimized staining protocol, allowing for a quantitative assessment of the predictive power of the technique under biologically relevant conditions. Due to the presence of necrosis in the model tumors, ring analysis was employed to characterize diagnostic accuracy as measured by receiver operator characteristic (ROC) curve analysis. Our findings demonstrate the robust nature of the DDSI technique even in the presence of variable biomarker expression and spatial patterns. These results support the continued development of this technology as a robust diagnostic tool for tumor margin assessment in resected specimens during BCS.
ABSTRACT
BACKGROUND: To safely perform acute intra-arterial revascularization procedures, use of sedative medications and paralytics is often necessary. During the conduct of the Interventional Management of Stroke trials (I and II), the level of sedation used periprocedurally varied. At some institutions, patients were paralyzed and intubated as part of the procedural standard of care while at other institutions no routine sedation protocol was followed. The aim of this study was to identify patient characteristics that would correlate with the need for deeper sedation and to explore whether levels of sedation relate to patient outcome. METHODS: 75 of 81 patients in the Interventional Management of Stroke II Study were studied. Patients had anterior circulation strokes and underwent angiography and/or intervention. Four sedation categories were defined and tested for factors potentially associated with the level of sedation. Clinical outcomes were also analyzed, including successful angiographic reperfusion and the occurrence of clinical complications. RESULTS: Only baseline National Institutes of Health Stroke Scale varied significantly by sedation category (p=0.01). Patients that were in the lower sedation category fared better, having a higher rate of good outcomes (p<0.01), lower death rates (p=0.02) and higher successful angiographic reperfusion rates (p=0.01). There was a significantly higher infection rate in patients receiving heavy sedation or pharmacologic paralysis (p=0.02) and a trend towards fewer groin related complications. CONCLUSION: In this small sample, patients not receiving sedation fared better, had higher rates of successful angiographic reperfusion and had fewer complications. Further examination of the indications for procedural sedation or paralysis and their effect on outcome is warranted.
Subject(s)
Hypnotics and Sedatives/administration & dosage , Preoperative Care/trends , Recovery of Function/drug effects , Stroke/diagnostic imaging , Stroke/therapy , Administration, Intravenous , Aged , Endovascular Procedures/methods , Endovascular Procedures/mortality , Endovascular Procedures/trends , Female , Humans , Hypnotics and Sedatives/adverse effects , Male , Middle Aged , Pilot Projects , Preoperative Care/adverse effects , Recovery of Function/physiology , Stroke/mortality , Thrombectomy/methods , Thrombectomy/mortality , Thrombectomy/trends , Tissue Plasminogen Activator/administration & dosage , Treatment OutcomeABSTRACT
OBJECTIVES: To explore the influence of obesity on outcomes of exercise capacity and disease impact in patients with chronic obstructive pulmonary disease (COPD) in response to pulmonary rehabilitation (PR) and to compare outcomes to those of normal weight and overweight counterparts. DESIGN: Secondary data analysis of clinical database. SETTING: St. James's Hospital, Dublin, Ireland. PARTICIPANTS: 155 participants with a primary diagnosis of COPD who completed a PR programme between 2012 and 2014. MAIN OUTCOME MEASURES: Exercise capacity evaluated using the Six Minute Walk Test (6MWT) and the COPD Assessment Test (CAT) evaluated disease impact. RESULTS: Walking distance in the 6MWT improved significantly [mean difference of 55m (95% CI: 42 to 68; p<0.001)] and similarly [F(2, 92)=1.434, p=0.24] across all BMI categories, although the level of improvement reached clinical significance in the normal/underweight and overweight categories only. Disease impact on the CAT score improved across all body mass index (BMI) classifications by 2.3 points (95% CI: 0.9 to 3.6; p<0.050) which reached clinical significance and did not vary across BMI categories [F(2, 80)=0.534, p=0.58]. CONCLUSION: Exercise capacity and self-report disease impact of individuals with COPD improved similarly in response to PR irrespective of BMI.
Subject(s)
Exercise Tolerance/physiology , Obesity/epidemiology , Pulmonary Disease, Chronic Obstructive/epidemiology , Pulmonary Disease, Chronic Obstructive/rehabilitation , Respiratory Therapy/methods , Age Factors , Aged , Body Mass Index , Exercise Test , Female , Humans , Ireland/epidemiology , Male , Middle Aged , Respiratory Function Tests , Sex FactorsABSTRACT
BACKGROUND AND PURPOSE: Uncertainty persists regarding the safety and efficacy of endovascular therapy of M2 occlusions following IV tPA. We reviewed the impact of revascularization on clinical outcomes in 83 patients with M2 occlusions in the Interventional Management of Stroke III trial according to specific M1-M2 segment anatomic features. MATERIALS AND METHODS: Perfusion of any M2 branch distinguished M2-versus-M1 occlusion. Prespecified modified TICI and arterial occlusive lesion revascularization and clinical mRS 0-2 end points at 90 days for endovascular therapy-treated M2 occlusions were analyzed. Post hoc analyses of the relationship of outcomes to multiple baseline angiographic M2 and M1 subgroup characteristics were performed. RESULTS: Of 83 participants with M2 occlusion who underwent endovascular therapy, 41.0% achieved mRS 0-2 at 90 days, including 46.6% with modified TICI 2-3 reperfusion compared with 26.1% with modified TICI 0-1 reperfusion (risk difference, 20.6%; 95% CI, -1.4%-42.5%). mRS 0-2 outcome was associated with reperfusion for M2 trunk (n = 9) or M2 division (n = 42) occlusions, but not for M2 branch occlusions (n = 28). Of participants with trunk and division occlusions, 63.2% with modified TICI 2a and 42.9% with modified TICI 2b reperfusion achieved mRS 0-2 outcomes; mRS 0-2 outcomes for M2 trunk occlusions (33%) did not differ from distal (38.2%) and proximal (26.9%) M1 occlusions. CONCLUSIONS: mRS 0-2 at 90 days was dependent on reperfusion for M2 trunk but not for M2 branch occlusions. For M2 division occlusions, good outcome with modified TICI 2b reperfusion did not differ from that in modified TICI 2a. M2 segment definition and occlusion location may contribute to differences in revascularization and good outcome between Interventional Management of Stroke III and other endovascular therapy studies.
Subject(s)
Arterial Occlusive Diseases/therapy , Cerebral Revascularization/methods , Cerebrovascular Disorders/therapy , Endovascular Procedures/methods , Stroke/therapy , Aged , Female , Humans , Male , Middle Aged , Treatment OutcomeABSTRACT
The eclipses of certain types of binary millisecond pulsars (i.e. 'black widows' and 'redbacks') are often studied using high-time-resolution, 'beamformed' radio observations. However, they may also be detected in images generated from interferometric data. As part of a larger imaging project to characterize the variable and transient sky at radio frequencies <200 MHz, we have blindly detected the redback system PSR J2215+5135 as a variable source of interest with the Low-Frequency Array (LOFAR). Using observations with cadences of two weeks - six months, we find preliminary evidence that the eclipse duration is frequency dependent (âν-0.4), such that the pulsar is eclipsed for longer at lower frequencies, in broad agreement with beamformed studies of other similar sources. Furthermore, the detection of the eclipses in imaging data suggests an eclipsing medium that absorbs the pulsed emission, rather than scattering it. Our study is also a demonstration of the prospects of finding pulsars in wide-field imaging surveys with the current generation of low-frequency radio telescopes.