First Measurement of η Meson Production in Neutrino Interactions on Argon with MicroBooNE

We present a measurement of η production from neutrino interactions on argon with the MicroBooNE detector. The modeling of resonant neutrino interactions on argon is a critical aspect of the neutrino oscillation physics program being carried out by the DUNE and Short Baseline Neutrino programs. η production in neutrino interactions provides a powerful new probe of resonant interactions, complementary to pion channels, and is particularly suited to the study of higher-order resonances beyond the Δ(1232). We measure a flux-integrated cross section for neutrino-induced η production on argon of 3.22±0.84(stat)±0.86(syst) 10^{-41}  cm^{2}/nucleon. By demonstrating the successful reconstruction of the two photons resulting from η production, this analysis enables a novel calibration technique for electromagnetic showers in GeV accelerator neutrino experiments.

First Double-Differential Measurement of Kinematic Imbalance in Neutrino Interactions with the MicroBooNE Detector

We report the first measurement of flux-integrated double-differential quasielasticlike neutrino-argon cross sections, which have been made using the Booster Neutrino Beam and the MicroBooNE detector at Fermi National Accelerator Laboratory. The data are presented as a function of kinematic imbalance variables which are sensitive to nuclear ground-state distributions and hadronic reinteraction processes. We find that the measured cross sections in different phase-space regions are sensitive to different nuclear effects. Therefore, they enable the impact of specific nuclear effects on the neutrino-nucleus interaction to be isolated more completely than was possible using previous single-differential cross section measurements. Our results provide precision data to help test and improve neutrino-nucleus interaction models. They further support ongoing neutrino-oscillation studies by establishing phase-space regions where precise reaction modeling has already been achieved.

First Measurement of Quasielastic Λ Baryon Production in Muon Antineutrino Interactions in the MicroBooNE Detector

We present the first measurement of the cross section of Cabibbo-suppressed Λ baryon production, using data collected with the MicroBooNE detector when exposed to the neutrinos from the main injector beam at the Fermi National Accelerator Laboratory. The data analyzed correspond to 2.2×10^{20} protons on target running in neutrino mode, and 4.9×10^{20} protons on target running in anti-neutrino mode. An automated selection is combined with hand scanning, with the former identifying five candidate Λ production events when the signal was unblinded, consistent with the GENIE prediction of 5.3±1.1 events. Several scanners were employed, selecting between three and five events, compared with a prediction from a blinded Monte Carlo simulation study of 3.7±1.0 events. Restricting the phase space to only include Λ baryons that decay above MicroBooNE's detection thresholds, we obtain a flux averaged cross section of 2.0_{-1.7}^{+2.2}×10^{-40}  cm^{2}/Ar, where statistical and systematic uncertainties are combined.

First Constraints on Light Sterile Neutrino Oscillations from Combined Appearance and Disappearance Searches with the MicroBooNE Detector

We present a search for eV-scale sterile neutrino oscillations in the MicroBooNE liquid argon detector, simultaneously considering all possible appearance and disappearance effects within the 3+1 active-to-sterile neutrino oscillation framework. We analyze the neutrino candidate events for the recent measurements of charged-current ν_{e} and ν_{μ} interactions in the MicroBooNE detector, using data corresponding to an exposure of 6.37×10^{20} protons on target from the Fermilab booster neutrino beam. We observe no evidence of light sterile neutrino oscillations and derive exclusion contours at the 95% confidence level in the plane of the mass-squared splitting Δm_{41}^{2} and the sterile neutrino mixing angles θ_{μe} and θ_{ee}, excluding part of the parameter space allowed by experimental anomalies. Cancellation of ν_{e} appearance and ν_{e} disappearance effects due to the full 3+1 treatment of the analysis leads to a degeneracy when determining the oscillation parameters, which is discussed in this Letter and will be addressed by future analyses.

Sensitivity of SARS-CoV-2 RNA polymerase chain reaction using a clinical and radiological reference standard

OBJECTIVES

Diagnostic tests for SARS-CoV-2 are important for epidemiology, clinical management, and infection control. Limitations of oro-nasopharyngeal real-time PCR sensitivity have been described based on comparisons of single tests with repeated sampling. We assessed SARS-CoV-2 PCR clinical sensitivity using a clinical and radiological reference standard.

METHODS

Between March-May 2020, 2060 patients underwent thoracic imaging and SARS-CoV-2 PCR testing. Imaging was independently double- or triple-reported (if discordance) by blinded radiologists according to radiological criteria for COVID-19. We excluded asymptomatic patients and those with alternative diagnoses that could explain imaging findings. Associations with PCR-positivity were assessed with binomial logistic regression.

RESULTS

901 patients had possible/probable imaging features and clinical symptoms of COVID-19 and 429 patients met the clinical and radiological reference case definition. SARS-CoV-2 PCR sensitivity was 68% (95% confidence interval 64-73), was highest 7-8 days after symptom onset (78% (68-88)) and was lower among current smokers (adjusted odds ratio 0.23 (0.12-0.42) p < 0.001).

CONCLUSIONS

In patients with clinical and imaging features of COVID-19, PCR test sensitivity was 68%, and was lower among smokers; a finding that could explain observations of lower disease incidence and that warrants further validation. PCR tests should be interpreted considering imaging, symptom duration and smoking status.

Symptomatic Cerebral Metastases In Malignant Pleural Mesothelioma: A Rare Case Report

Casestudy: Malignant mesothelioma is an aggressive tumor with dismal prognosis. Incidence in the United States is approximately 3300 cases/year, and the most common site is the pleura. Although mesothelioma is usually a locally invasive tumor, distant metastases to liver, adrenal glands, kidney and contralateral lung have been described. Brain metastases are observed in less than 3% of metastatic cases and most have been detected incidentally at autopsy. Symptomatic brain metastases are unusual. We describe a case of a 77 year old gentleman with history of occupational asbestos exposure who presented with shortness of breath and dry cough. The radiological investigations revealed left pleural thickening with pleural effusion, which on biopsy proved to be biphasic malignant mesothelioma. Despite multi-modality therapy, the patient showed local disease progression. Following 37 months of initial diagnosis, he developed progressive left-sided weakness. Brain MRI revealed a 1.7 cm enhancing mass involving right posterior frontal lobe, with extensive edema in the surrounding tissue. On biopsy, mass was composed of nests and sheets of round-to-spindled cells with scant eosinophilic cytoplasm, separated by fibrous septa. Brisk mitotic activity and necrosis were present. There was a sharp border with adjacent brain parenchyma. The tumor was positive for WT-1, calretinin, and cytokeratins and negative for Ber-Ep4 and glial fibrillary acid protein by immunohistochemistry. The histological appearance of the tumor was similar to that of the pleural biopsy. Thus a diagnosis of metastatic malignant mesothelioma was made. This solitary metastasis was treated with resection and post-operative stereotactic radiation. The 3-month follow-up brain MRI revealed nodular enhancement within the cavity with multiple supra- and infra-tentorial enhancing lesions, and leptomeningeal enhancement, most consistent with progressing metastatic disease. With the advancements in treatment options that has improved survival in malignant mesothelioma patients, the pathologist and neurosurgeon should be aware of the diagnostic possibility intra-operatively which may alter the management.

An international survey on hybrid imaging: do technology advances preempt our training and education efforts?

BACKGROUND

Hybrid PET/CT and PET/MRI are increasingly important technologies in the evaluation of malignancy and require cooperation between radiologists and specialists in molecular imaging. The aim of our study was to probe the mindsets of radiological and nuclear medicine professionals in regard to current hybrid imaging practice and to assess relevant training aspirations and perceived shortfalls, particularly amongst young professionals. In this context, we initiated an international survey on "Hybrid Imaging Training".

METHODS

An online survey was prepared on-line and launched on October-2, 2016. It was composed of 17 multiple-choice and open questions regarding the professional background, a perspective on hybrid imaging training efforts and lessons to be learned from disparate craft groups. The survey ran for 2 weeks. We report total responses per category and individual free-text responses.

RESULTS

In total, 248 responses were collected with a mean age of all responders of (41 ± 11) y. Overall, 36% were within the target age range of (20-35) y. Across all responders, the majority (72%) commented on there being too few hybrid imaging experts in their country, whereas only 1% said that there were too many. Three quarters of the responders were in favour of a curriculum allowing sub-specialisation in hybrid imaging. With respect to reporting of hybrid imaging, confidence increased with age. The average rating across all responders on the level of cooperation among the two specialties suggested a low overall level of satisfaction. However, the survey feedback indicated the local (on-site) cooperation being somewhat better than the perceived cooperation between the relevant associations on a European level.

CONCLUSION

We consider these results to represent an appropriate cross-section of professional opinions of imaging experts across different demographic and hierarchical levels. Collectively they provide evidence supporting a need to address current shortfalls in developing hybrid imaging expertise through national educational plans, and, thus, contribute to helping improve patient care.

Behaviour of Perforated Plates under Plane Stress

A theoretical method is developed for determining the elastic behaviour of end-loaded plates completely perforated with closely spaced circular holes forming a square or diagonal pattern. The general method of solution has been verified by experimental work for particular types of loading. The following problems are considered in detail: (1) Unequal uniform applied extensions in the × and y directions; (2) Uniform applied shear. Using a digital computer, complete solutions have been obtained for the stress distribution in plates with holes having pitch to diameter ratios of 1·2, 1·4, 1·7, 2·0, and 3·0, respectively. These solutions have been used to obtain design curves for (1) effective Young's modulus; (2) effective shear modulus; (3) effective Poisson's ratio; (4) variation of applied load; (5) variation of stress across ligaments; (6) stress concentration factors. For plates with a square or diagonal system of holes, the above curves are sufficiently extensive to be applicable to all problems likely to occur in practice.

Traumatic brain injury imaging research roadmap

The past decade has seen impressive advances in the types of neuroimaging information that can be acquired in patients with traumatic brain injury. However, despite this increase in information, understanding of the contribution of this information to prognostic accuracy and treatment pathways for patients is limited. Available techniques often allow us to infer the presence of microscopic changes indicative of alterations in physiology and function in brain tissue. However, because histologic confirmation is typically lacking, conclusions reached by using these techniques remain solely inferential in almost all cases. Hence, a need exists for validation of these techniques by using data from large population samples that are obtained in a uniform manner, analyzed according to well-accepted procedures, and correlated with closely monitored clinical outcomes. At present, many of these approaches remain confined to population-based research rather than diagnosis at an individual level, particularly with regard to traumatic brain injury that is mild or moderate in degree. A need and a priority exist for patient-centered tools that will allow advanced neuroimaging tools to be brought into clinical settings. One barrier to developing these tools is a lack of an age-, sex-, and comorbidities-stratified, sequence-specific, reference imaging data base that could provide a clear understanding of normal variations across populations. Such a data base would provide researchers and clinicians with the information necessary to develop computational tools for the patient-based interpretation of advanced neuroimaging studies in the clinical setting. The recent "Joint ASNR-ACR HII-ASFNR TBI Workshop: Bringing Advanced Neuroimaging for Traumatic Brain Injury into the Clinic" on May 23, 2014, in Montreal, Quebec, Canada, brought together neuroradiologists, neurologists, psychiatrists, neuropsychologists, neuroimaging scientists, members of the National Institute of Neurologic Disorders and Stroke, industry representatives, and other traumatic brain injury stakeholders to attempt to reach consensus on issues related to and develop consensus recommendations in terms of creating both a well-characterized normative data base of comprehensive imaging and ancillary data to serve as a reference for tools that will allow interpretation of advanced neuroimaging tests at an individual level of a patient with traumatic brain injury. The workshop involved discussions concerning the following: 1) designation of the policies and infrastructure needed for a normative data base, 2) principles for characterizing normal control subjects, and 3) standardizing research neuroimaging protocols for traumatic brain injury. The present article summarizes these recommendations and examines practical steps to achieve them.

Phase II trial evaluating the feasibility of interdigitating folfox with chemoradiotherapy in locally advanced and metastatic rectal cancer

BACKGROUND

Patients (pts) with metastatic rectal cancer and symptomatic primary, require local and systemic control. Chemotherapy used during chemoradiotherapy (CRT) is adequate for radiosensitisation, but suboptimal for systemic control. The aim of this phase II study was to assess tolerability, local/systemic benefits, of a novel regimen delivering interdigitating intensive chemotherapy with radical CRT.

METHODS

Eligible pts had untreated synchronous symptomatic primary/metastatic rectal cancer. A total of 12 weeks of treatment with split-course pelvic CRT (total 50.4 Gy with concurrent oxaliplatin and 5-FU infusion) alternating with FOLFOX chemotherapy. All pts staged with CT, MRI and FDG-PET pre and post treatment.

RESULTS

Twenty-six pts were treated. Rectal primary MRI stage: T3 81% and T4 15%. Liver metastases in 81%. Twenty-four pts (92%) completed the 12-week regimen. All patients received planned RT dose, and for both agents over 88% of patients achieved a relative dose intensity of >75%. Grade 3 toxicities: neutropenia 23%, diarrhoea 15%, and radiation skin reaction 12%. Grade 4 toxicity: neutropenia 15%. FDG-PET metabolic response rate for rectal primary 96%, and for metastatic disease 60%.

CONCLUSIONS

Delivery of interdigitating chemotherapy with radical CRT was feasible to treat both primary and metastatic rectal cancer. High completion and response rates were encouraging.

Staging with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) for nonseminomatous germ cell tumor (NSGCT): The Peter MacCallum Cancer Centre experience

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Background: We retrospectively evaluated our single institution experience using FDG-PET as part of initial assessment of stage I/II NSGCT. Previous studies by de Wit et al and the TE22 trial concluded that there was a very limited role for PET staging in NSGCT. Despite these results, PET continues to be utilised in our center. Methods: With local ethics approval, the PET center database at Peter MacCallum Cancer Centre (PMCC) was used to identify a series of 26 patients with NSGCT who underwent FDG-PET as part of staging investigations between 1998 and 2008. Demographic and clinical information was collected using electronic and paper medical records. Histological samples were reviewed if additional information was required. Results: Lymphovascular invasion (LVI) was present in 10 (38%) of orchiectomy specimens. 15 patients had stage I disease on both CT and PET. PET upstaged 7 patients from stage I to stage II disease, and all upstaged patients received systemic chemotherapy (3 cycles BEP). 1 patient with stage I disease on PET and CT received adjuvant chemotherapy (2 cycles EP). 3 patients with LVI and stage 1 disease on CT and PET underwent surveillance. With median follow-up of 33 months (range 1–94), all patients were alive without disease recurrence, although 1 patient was treated for a second primary NSGCT. Conclusions: Using PET images, we were able to identify patients with low volume metastatic disease and achieve 100% relapse-free survival rates. Despite the small sample size, these results are promising and are better than expected based on published data. This might be explained by the quality of the PET imaging, including attenuation correction and combined CT/PET for enhanced sensitivity interpreting retroperitoneal disease. Further evaluation of PET is warranted, particularly in patients with equivocal CTs or with the high-risk feature of LVI. [Table: see text]

No significant financial relationships to disclose.

Laser-assisted microdissection: a new tool for aquatic molecular parasitology

Laser-assisted microdissection (LMD) has been developed to isolate distinct cell populations from heterogeneous tissue sections, cytological preparations, or live cell samples. Downstream applications typically include gene expression studies using real-time PCR and array platforms, diagnostic PCR, and protein expression studies. LMD techniques are now commonplace in mainstream biological research and clearly have suitable applications in the field of aquatic pathology and parasitology. The present study used LMD to isolate 2 dinoflagellate parasites (Hematodinium spp.) from formalin-fixed paraffin-embedded tissue sections from 2 crustacean hosts, Cancer pagurus and Portunus trituberculatus. DNA was isolated from LMD parasite preparations, and partial regions (up to 300 bp) of the small subunit and the first internal transcribed spacer region of the rRNA gene complex from the Hematodinium spp. were PCR amplified using diagnostic primers. The amplification products were sequenced to confirm the identity of the targeted regions. The techniques, applications, and limitations of LMD to address questions in aquatic molecular pathology and parasitology are discussed.

Utility of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) in the staging, radiotherapy planning and prognostication of anal cancer

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Background: Accurate inguinal and pelvic nodal staging in anal cancer is important for prognosis and planning of (chemo)radiation fields. There is strong evidence for the impact of FDG-PET in staging and management of cancer, with early reports of an increasing role in outcome prognostication for a number of tumours. We aimed to determine the impact of FDG-PET on the nodal staging, radiotherapy planning and prognostication of patients with primary anal cancer. Methods: Sixty-two consecutive patients with anal cancer referred to a single tertiary oncology centre between August 1997 and November 2005 were staged with conventional imaging (CIm), computed tomography, magnetic resonance imaging and chest x-ray and by FDG-PET. The stage determined by CIm and the proposed management plan was prospectively recorded and changes in stage and management as a result of FDG-PET assessed. Patients were treated using uniform radiotherapy technique and dose. The accuracy of changes and prognostication of FDG-PET was validated by subsequent clinical follow-up. Kaplan-Meier survival analysis was used to assess survival for the cohort and by FDG-PET and CIm stage. Results: The TNM stage group was changed in 23% (14/62) as a result of FDG-PET (15% up-staged, 8% down-staged). Fourteen percent of T1 patients (3/22), 42% of T2 patients (10/24) and 38% of T3–4 patients (6/16), assessed using CIm, had a change in their N or M stage following FDG-PET. Sensitivity for nodal disease by FDG-PET and CIm was 92% and 72% respectively. The staging FDG-PET scan altered management intent in 3% (2/62), and altered radiotherapy fields in 13% (8/62). Estimated 5 year overall survival and progression free survival (PFS) for the cohort was 77.3% (95% CI 55.3%-90.4%) and 72.2% (95% CI 51.5%-86.4%) respectively. Estimated 5 year PFS for FDG-PET and CIm staged N2–3 disease was 70% (95% CI 42.8%-87.9%) and 55.3% (95% CI 23.3%-83.4%) respectively. Conclusions: FDG-PET shows increased sensitivity over CIm for staging nodal disease in anal cancer and changes treatment intent or radiotherapy fields in a significant proportion of patients. Improved 5 year PFS for FDG-PET staged N2–3 disease could be consistent with more accurate nodal staging and radiotherapy targeting.

No significant financial relationships to disclose.

Measurements of the generalized electric and magnetic polarizabilities of the proton at low Q2 using the virtual-compton-scattering reaction

The mean square polarizability radii of the proton have been measured for the first time in a virtual-Compton-scattering experiment performed at the MIT-Bates out-of-plane scattering facility. Response functions and polarizabilities obtained from a dispersion analysis of the data at Q2 = 0.057 GeV2/c2 are in agreement with O(p3) heavy baryon chiral perturbation theory. The data support the dominance of mesonic effects in the polarizabilities.