Early spectra of the gravitational wave source GW170817: Evolution of a neutron star merger.

On 17 August 2017, Swope Supernova Survey 2017a (SSS17a) was discovered as the optical counterpart of the binary neutron star gravitational wave event GW170817. We report time-series spectroscopy of SSS17a from 11.75 hours until 8.5 days after the merger. Over the first hour of observations, the ejecta rapidly expanded and cooled. Applying blackbody fits to the spectra, we measured the photosphere cooling from [Formula: see text] to [Formula: see text] kelvin, and determined a photospheric velocity of roughly 30% of the speed of light. The spectra of SSS17a began displaying broad features after 1.46 days and evolved qualitatively over each subsequent day, with distinct blue (early-time) and red (late-time) components. The late-time component is consistent with theoretical models of r-process-enriched neutron star ejecta, whereas the blue component requires high-velocity, lanthanide-free material.

Light curves of the neutron star merger GW170817/SSS17a: Implications for r-process nucleosynthesis.

On 17 August 2017, gravitational waves (GWs) were detected from a binary neutron star merger, GW170817, along with a coincident short gamma-ray burst, GRB 170817A. An optical transient source, Swope Supernova Survey 17a (SSS17a), was subsequently identified as the counterpart of this event. We present ultraviolet, optical, and infrared light curves of SSS17a extending from 10.9 hours to 18 days postmerger. We constrain the radioactively powered transient resulting from the ejection of neutron-rich material. The fast rise of the light curves, subsequent decay, and rapid color evolution are consistent with multiple ejecta components of differing lanthanide abundance. The late-time light curve indicates that SSS17a produced at least ~0.05 solar masses of heavy elements, demonstrating that neutron star mergers play a role in rapid neutron capture (r-process) nucleosynthesis in the universe.

Multi-Center Study of Diffusion-Weighted Imaging in Coma After Cardiac Arrest.

BACKGROUND: The ability to predict outcomes in acutely comatose cardiac arrest survivors is limited. Brain diffusion-weighted magnetic resonance imaging (DWI MRI) has been shown in initial studies to be a simple and effective prognostic tool. This study aimed to determine the predictive value of previously defined DWI MRI thresholds in a multi-center cohort. METHODS: DWI MRIs of comatose post-cardiac arrest patients were analyzed in this multi-center retrospective observational study. Poor outcome was defined as failure to regain consciousness within 14 days and/or death during the hospitalization. The apparent diffusion coefficient (ADC) value of each brain voxel was determined. ADC thresholds and brain volumes below each threshold were analyzed for their correlation with outcome. RESULTS: 125 patients were included in the analysis. 33 patients (26%) had a good outcome. An ADC value of less than 650 × 10(-6) mm(2)/s in ≥10% of brain volume was highly specific [91% (95% CI 75-98)] and had a good sensitivity [72% (95% CI 61-80)] for predicting poor outcome. This threshold remained an independent predictor of poor outcome in multivariable analysis (p = 0.002). An ADC value of less than 650 × 10(-6) mm(2)/s in >22% of brain volume was needed to achieve 100% specificity for poor outcome. CONCLUSIONS: In patients who remain comatose after cardiac arrest, quantitative DWI MRI findings correlate with early recovery of consciousness. A DWI MRI threshold of 650 × 10(-6) mm(2)/s in ≥10% of brain volume can differentiate patients with good versus poor outcome, though in this patient population the threshold was not 100% specific for poor outcome.

Perfusion-based selection for endovascular reperfusion therapy in anterior circulation acute ischemic stroke.

BACKGROUND AND PURPOSE: Controversy exists about the role of perfusion imaging in patient selection for endovascular reperfusion therapy in acute ischemic stroke. We hypothesized that perfusion imaging versus noncontrast CT- based selection would be associated with improved functional outcomes at 3 months. MATERIALS AND METHODS: We reviewed consecutive patients with anterior circulation strokes treated with endovascular reperfusion therapy within 8 hours and with baseline NIHSS score of ≥8. Baseline clinical data, selection mode (perfusion versus NCCT), angiographic data, complications, and modified Rankin Scale score at 3 months were collected. Using multivariable logistic regression, we assessed whether the mode of selection for endovascular reperfusion therapy (perfusion-based versus NCCT-based) was independently associated with good outcome. RESULTS: Two-hundred fourteen patients (mean age, 67.2 years; median NIHSS score, 18; MCA occlusion 74% and ICA occlusion 26%) were included. Perfusion imaging was used in 76 (35.5%) patients (39 CT and 37 MR imaging). Perfusion imaging-selected patients were more likely to have good outcomes compared with NCCT-selected patients (55.3 versus 33.3%, P = .002); perfusion selection by CT was associated with similar outcomes as that by MR imaging (CTP, 56.; MR perfusion, 54.1%; P = .836). In multivariable analysis, CT or MR perfusion imaging selection remained strongly associated with good outcome (adjusted OR, 2.34; 95% CI, 1.22-4.47), independent of baseline severity and reperfusion. CONCLUSIONS: In this multicenter study, patients with acute ischemic stroke who underwent perfusion imaging were more than 2-fold more likely to have good outcomes following endovascular reperfusion therapy. Randomized studies should compare perfusion imaging with NCCT imaging for patient selection for endovascular reperfusion therapy.

T1 gadolinium enhancement of intracranial atherosclerotic plaques associated with symptomatic ischemic presentations.

BACKGROUND AND PURPOSE: Contrast enhancement of intracranial atherosclerotic plaques has recently been investigated using high field and high resolution MR imaging as a risk factor in the development of ischemic stroke. We studied the reliability of conventional MR imaging at 1.5T in evaluating intraplaque enhancement and its relationship with acute cerebrovascular ischemic presentations in patients with severe intracranial atherosclerotic disease. MATERIALS AND METHODS: We retrospectively identified and analyzed 19 patients with 22 high-grade intracranial atherosclerotic disease plaques (>70% stenosis) in vessels cross-sectionally visualized by neuroanatomic MR imaging. Atherosclerotic plaques were classified as asymptomatic or symptomatic. Two blinded neuroradiologists independently ranked each lesion for the presence of intraplaque enhancement by use of a 5-point scale (1-5). Furthermore, plaque enhancement was quantified as the relative change in T1WI spin-echo signal intensity (postcontrast/precontrast) in the vessel wall at the site of each intracranial atherosclerotic disease lesion. RESULTS: Intraplaque enhancement was observed in 7 of 10 (70%) symptomatic plaques, in contrast to 1 of 12 (8%) asymptomatic plaques. Interobserver reliability correlated well for intraplaque enhancement (κ = 0.82). The degree of relative plaque enhancement in symptomatic versus asymptomatic lesions (63% versus 23%) was statistically significant (P = .001, t test). CONCLUSIONS: In this pilot study, we determined that intraplaque enhancement could be reliably evaluated with the use of cross-sectional imaging and analysis of vessels/plaques by use of conventional neuroanatomic MR imaging protocols. In addition, we observed a strong association between intraplaque enhancement in severe intracranial atherosclerotic disease lesions and ischemic events with the use of conventional MR imaging. Our preliminary study suggests that T1 gadolinium-enhancing plaques may be an indicator of progressing or symptomatic intracranial atherosclerotic disease.

MRI guides diagnostic approach for ischaemic stroke.

BACKGROUND AND AIM: Identification of ischaemic stroke subtype currently relies on clinical evaluation supported by various diagnostic studies. The authors sought to determine whether specific diffusion-weighted MRI (DWI) patterns could reliably guide the subsequent work-up for patients presenting with acute ischaemic stroke symptoms. METHODS: 273 consecutive patients with acute ischaemic stroke symptoms were enrolled in this prospective, observational, single-centre NIH-sponsored study. Electrocardiogram, non-contrast head CT, brain MRI, head and neck magnetic resonance angiography (MRA) and transoesophageal echocardiography were performed in this prespecified order. Stroke neurologists determined TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification on admission and on discharge. Initial TOAST stroke subtypes were compared with the final TOAST subtype. If the final subtype differed from the initial assessment, the diagnostic test deemed the principal determinant of change was recorded. These principal determinants of change were compared between a CT-based and an MRI-based classification schema. RESULTS: Among patients with a thromboembolic DWI pattern, transoesophageal echocardiography was the principal determinant of diagnostic change in 8.8% versus 0% for the small vessel group and 1.7% for the other group (p<0.01). Among patients with the combination of a thromboembolic pattern on MRI and a negative cervical MRA, transoesophageal echocardiography led to a change in diagnosis in 12.1%. There was no significant difference between groups using a CT-based scheme. CONCLUSIONS: DWI patterns appear to predict stroke aetiologies better than conventional methods. The study data suggest an MRI-based diagnostic algorithm that can potentially obviate the need for echocardiography in one-third of stroke patients and may limit the number of secondary extracranial vascular imaging studies to approximately 10%.

Critical care of acute ischemic stroke.

Advances in neurologic therapeutics and intensive care medicine have expanded the arsenal of treatments available for the critical care of ischemic stroke. Several agents are available for acute reperfusion of the ischemic brain. These include intravenous recombinant tissue-plasminogen activator (rtPA), which is effective in a 3-hour time window, and intra-arterial thrombolytics, which may be effective within 6 hours. In addition, newer agents such as Ancrod and abciximab may be effective within the acute time period. Efforts to prevent secondary brain injury in critically ill patients with stroke often include prevention and reduction of fever, induced hypertension, and mechanical ventilation. Finally, death due to severe brain edema after massive hemispheric infarction can often be prevented with surgical or medical intervention. Unfortunately, there is a critical lack of well-designed clinical studies to guide the clinician in the use of these interventions. In addition, there is concern that some of these interventions may preserve life at the cost of quality of life. This article reviews the evidence behind these approaches to the critical care of ischemic stroke.

Juvenile rheumatoid arthritis.

Juvenile rheumatoid arthritis occurs quite rarely, but should be suspected in a child presenting with arthralgias and systemic signs of sepsis. Once diagnosed, treatment necessitates a multidisciplinary approach to address the social, medical, and surgical issues. Current research into serologic methods of diagnosis shows great promise for better classifying patients, which ultimately will facilitate treatment. Recent well-designed randomized trials are providing better objective information on pharmacologic treatment alternatives. Surgery is reserved for recalcitrant cases that fail medical and occupational therapy. The goals of surgery in children with JRA are to delay or prevent joint destruction and closure of the epiphysis, to prevent or correct deformity, to decrease pain, and to maintain growth and joint motion.

Endoscopic carpal tunnel release.

Carpal tunnel syndrome (CTS) is a common affliction of the upper extremity with the classic symptoms of numbness in the radial three and one-half digits, and pain often secondary to repetitive motions. The 1990s have seen a surge in the incidence of CTS, possibly because of increased awareness, recognition, or an increased prevalence of repetitive motion-type disorders. Furthermore, with the increasing use of computers, more people are sitting at keyboards entering text and data, which may lead to more cases of CTS. Recently, the technique of endoscopic carpal tunnel release has gained increased notoriety. The reported benefits include decreased surgical time, decreased postoperative attention, early return to work, diminished pillar pain, and increased thenar strength.

Treatment of ununited tibial fractures: a comparison of surgery and pulsed electromagnetic fields (PEMF).

The use of pulsed electromagnetic fields (PEMF) is gaining acceptance for the treatment of ununited fractures. The results of 44 articles published in the English language literature have been compiled to assess the effectiveness of PEMF vs surgical therapy. For ununited tibial fractures, 81% of reported cases healed with PEMF vs 82% with surgery. After multiple failed surgeries, the success rate of PEMF is reported to be greater than with surgery; this discrepancy increases with additional numbers of prior surgeries. In infected nonunions, the results of surgical treatment decreased by 21% and were less than the results utilizing PEMF (69% vs 81%). In open fractures, surgical healing exceeded PEMF (89% vs 78%), whereas in closed injuries PEMF cases healed more frequently (85% vs 79%). In general, PEMF treatment of ununited fractures has proved to be more successful than noninvasive traditional management and at least as effective as surgical therapies. Given the costs and potential dangers of surgery, PEMF should be considered an effective alternative. Experience supports its role as a successful method of treatment for ununited fractures of the tibia.

Computerized tomography of the patellofemoral joint before and after lateral release or realignment.

Computerized tomography (CT) provides an accurate diagnostic tool for evaluating tilt and subluxation of the patella. Using a previously described technique, this study reviews 62 computerized tomograms, including those of 21 patients before and after lateral release or anteromedial tibial tubercle transfer. One patient was evaluated before and after soft-tissue realignment of the patella. Additional CT studies were evaluated to establish the most appropriate reference line for determining patellar tilt. Results show that lateral retinacular release effectively reduces abnormal patellar tilting as determined by CT. Anteromedial tibial tubercle transfer similarly reduces abnormal tilt. Patellar subluxation may improve substantially following either lateral release or anteromedial tibial tubercle transfer, but this study suggests that correction of subluxation is less consistent than reduction of abnormal tilt with tibial tubercle transfer or lateral release alone. Once articular degeneration has progressed to the point of facet collapse, lateral release fails to restore normal tilt.

Ventriculocholecystic shunt. A mortality report.

Ventriculocholecystic shunts are not commonly used for the treatment of hydrocephalus. We present a case of a child who underwent such a procedure and died of unusual complications. This case represents a unique juxtaposition of uncommon neurosurgical entities and complications including acquired communicating hydrocephalus, bilious ventriculitis secondary to a ventriculocholecystic shunt, and pulmonary edema. The unusual features of this case are discussed and emphasis is placed on the pathophysiologic findings.

Criteria for using imaging ultrasound during brain and spinal cord surgery.

Imaging ultrasonography was performed during 23 brain and five spinal cord operations with real-time B-mode instruments. Criteria for the utilization of ultrasound at neurosurgical procedures were identified in terms of assistance in the diagnosis or better definition of lesions. The diagnosis criteria were detection and exclusion. Because of the accuracy of preoperative imaging, usually little further help was provided by operative ultrasonography in detecting previously totally unknown abnormalities or excluding lesions found on positive studies. The definition criteria were localization, distinction of tissue features, and assessment of spatial relations. Operative ultrasonography was most useful when applied on the basis of these definition criteria. Operative ultrasonography was considered to be useful in 22 of 28 operations (79 per cent) in which it assisted in exposing, accessing, and extirpating disease.

Response strategies for chart requests from psychiatric inpatients.

Of 452 patients seen during one year on a medical-school-affiliated general hospital psychiatric unit, 26 requested to see their charts. These patients tended to be younger, more likely to have character disorders, and less likely to have an affective disorder than patients who did not make chart requests. The apparent increase in the number of patients who ask to see their records may be linked to increasing medical consumerism. Rather than causing therapists to become defensive, record requests should provide an opportunity for education and treatment. The authors outline methods of interpreting and responding to chart requests.