Acute appendicitis: prospective evaluation of a diagnostic algorithm integrating ultrasound and low-dose CT to reduce the need of standard CT

Objectives: To evaluate an algorithm integrating ultrasound and low-dose unenhanced CT with oral contrast medium (LDCT) in the assessment of acute appendicitis, to reduce the need of conventional CT. Methods: Ultrasound was performed upon admission in 183 consecutive adult patients (111 women, 72 men, mean age 32) with suspicion of acute appendicitis and a BMI between 18.5 and 30 (step 1). No further examination was recommended when ultrasound was positive for appendicitis, negative with low clinical suspicion, or demonstrated an alternative diagnosis. All other patients underwent LDCT (30mAs) (step 2). Standard intravenously enhanced CT (180mAs) was performed after indeterminate LDCT (step 3). Results: No further imaging was recommended after ultrasound in 84 (46%) patients; LDCT was obtained in 99 (54%). LDCT was positive or negative for appendicitis in 81 (82%) of these 99 patients, indeterminate in 18 (18%) who underwent standard CT. Eighty-six (47%) of the 183 patients had a surgically proven appendicitis. The sensitivity and specificity of the algorithm were 98.8% and 96.9%. Conclusions: The proposed algorithm achieved high sensitivity and specificity for detection of acute appendicitis, while reducing the need for standard CT and thus limiting exposition to radiation and to intravenous contrast medi

Acute on Chronic Thromboembolic Pulmonary Hypertension: Case Series and Review of Management

Chronic thromboembolic pulmonary hypertension (CTEPH) is a distinct form of precapillary pulmonary hypertension classified as group 4 by the World Symposium on Pulmonary Hypertension (WSPH) and should be excluded during an episode of acute pulmonary embolism (PE). Patients presenting to emergency departments with sudden onset of signs and symptoms of acute PE may already have a pre-existing CTEPH condition decompensated by the new PE episode. Identifying an underlying and undiagnosed CTEPH during acute PE, while challenging, is an important consideration as it will alter the patients' acute and long-term management. Differential diagnosis and evaluation require an interdisciplinary expert team. Analysis of the clinical condition, the CT angiogram, and the hemodynamic situation are important considerations; patients with CTEPH usually have significantly higher sPAP at the time of index PE, which is unusual and unattainable in the context of acute PE and a naïve right ventricle. The imaging may reveal signs of chronic disease such as right ventricle hypertrophy bronchial collaterals and atypical morphology of the thrombus. There is no standard for the management of acute on chronic CTEPH. Herein, we provide a diagnostic and management algorithm informed by several case descriptions and a review of the literature

Crystallization in mass-asymmetric electron-hole bilayers

We consider a \textit{mass-asymmetric} electron and hole bilayer. Electron and hole Coulomb correlations and electron and hole quantum effects are treated on first princles by path integral Monte Carlo methods. For a fixed layer separation we vary the mass ratio $M$ of holes and electrons between 1 and 100 and analyze the structural changes in the system. While, for the chosen density, the electrons are in a nearly homogeneous state, the hole arrangement changes from homogeneous to localized, with increasing $M$ which is verified for both, mesoscopic bilayers in a parabolic trap and for a macroscopic system.Comment: 10 pages, latex (styles files included

First direct observation of two protons in the decay of 45^{45}Fe with a TPC

The decay of the ground-state two-proton emitter 45Fe was studied with a time-projection chamber and the emission of two protons was unambiguously identified. The total decay energy and the half-life measured in this work agree with the results from previous experiments. The present result constitutes the first direct observation of the individual protons in the two-proton decay of a long-lived ground-state emitter. In parallel, we identified for the first time directly two-proton emission from 43Cr, a known beta-delayed two-proton emitter. The technique developped in the present work opens the way to a detailed study of the mechanism of ground-state as well as beta-delayed two-proton radioactivity.Comment: 4 pages, 5 figure

New pathway to bypass the 15O waiting point

We propose the sequential reaction process $^{15}$O($p$,$\gamma)(\beta^{+}$)$^{16}$O as a new pathway to bypass of the $^{15}$O waiting point. This exotic reaction is found to have a surprisingly high cross section, approximately 10$^{10}$ times higher than the $^{15}$O($p$,$\beta^{+}$)$^{16}$O. These cross sections were calculated after precise measurements of energies and widths of the proton-unbound $^{16}$F low lying states, obtained using the H($^{15}$O,p)$^{15}$O reaction. The large $(p,\gamma)(\beta^{+})$ cross section can be understood to arise from the more efficient feeding of the low energy wing of the ground state resonance by the gamma decay. The implications of the new reaction in novae explosions and X-ray bursts are discussed.Comment: submitte

Improved results of induction chemoradiation before surgical intervention for selected patients with stage IIIA-N2 non–small cell lung cancer

ObjectiveOptimal management of stage IIIA-N2 non–small cell lung cancer remains controversial. The surgical arm of the North American Intergroup 0139 trial was adopted as the standard treatment for patients with resectable N2 disease at the University Health Network. Results after 7 years of experience are reported.MethodsThis is a retrospective study of consecutive patients with biopsy-proved T1-3 N2 M0 lung cancer who underwent induction chemoradiation before surgical intervention from January 1997 through August 2004. Induction chemotherapy consisted of cisplatin, 50 mg/m2, on days 1 and 8; etoposide, 50 mg/m2, on days 1 to 5, weeks 1 and 5; and concurrent daily external beam radiotherapy to 45 Gy. Lung resection was performed within 6 weeks of completion of chemoradiation, followed by 2 further cycles of consolidation chemotherapy.ResultsBetween January 1997 and August 2004, 40 patients were treated according to this protocol (25% T1, 62.5% T2, 7.5% T3, and 5% T4). Overall and disease-free median survivals were 40 and 37.1 months, respectively, whereas overall and disease-free 3-year survivals were 51.7% and 52.3%, respectively. R0 resection was achieved in 92.5%. The overall operative mortality rate was 7.5% (0% for lobectomy and 27% for pneumonectomy). Notably, all mortalities occurred within the first 2 years of our experience with this regimen.ConclusionChemoradiation before pulmonary resection in carefully selected patients with surgically resectable stage IIIA (N2) non–small cell lung cancer can lead to improved overall and disease-free survival

Probing Nuclear forces beyond the drip-line using the mirror nuclei 16^{16}N and 16^{16}F

Radioactive beams of $^{14}$O and $^{15}$O were used to populate the resonant states 1/2$^+$, 5/2$^+$ and $0^-,1^-,2^-$ in the unbound $^{15}$F and $^{16}$F nuclei respectively by means of proton elastic scattering reactions in inverse kinematics. Based on their large proton spectroscopic factor values, the resonant states in $^{16}$F can be viewed as a core of $^{14}$O plus a proton in the 2s$_{1/2}$ or 1d$_{5/2}$ shell and a neutron in 1p$_{1/2}$. Experimental energies were used to derive the strength of the 2s$_{1/2}$-1p$_{1/2}$ and 1d$_{5/2}$-1p$_{1/2}$ proton-neutron interactions. It is found that the former changes by 40% compared with the mirror nucleus $^{16}$N, and the second by 10%. This apparent symmetry breaking of the nuclear force between mirror nuclei finds explanation in the role of the large coupling to the continuum for the states built on an $\ell=0$ proton configuration.Comment: 6 pages, 3 figures, 2 tables, accepted for publication as a regular article in Physical Review

Potential of hybrid 18F-fluorocholine PET/MRI for prostate cancer imaging

Purpose: To report the first results of hybrid 18F-fluorocholine PET/MRI imaging for the detection of prostate cancer. Methods: This analysis included 26 consecutive patients scheduled for prostate PET/MRI before radical prostatectomy. The examinations were performed on a hybrid whole-body PET/MRI scanner. The MR acquisitions which included T2-weighted, diffusion-weighted and dynamic contrast-enhanced sequences were followed during the same session by whole-body PET scans. Parametric maps were constructed to measure normalized T2-weighted intensity (nT2), apparent diffusion coefficient (ADC), volume transfer constant (K trans), extravascular extracellular volume fraction (v e) and standardized uptake values (SUV). With pathology as the gold standard, ROC curves were calculated using logistic regression for each parameter and for the best combination with and without PET to obtain a MR model versus a PETMR model. Results: Of the 26 patients initially selected, 3 were excluded due to absence of an endorectal coil (2 patients) or prosthesis artefacts (1 patient). In the whole prostate, the area under the curve (AUC) for SUVmax, ADC, nT2, K trans and v e were 0.762, 0.756, 0.685, 0.611 and 0.529 with a best threshold at 3.044 for SUVmax and 1.075×10−3mm2/s for ADC. The anatomical distinction between the transition zone and the peripheral zone showed the potential of the adjunctive use of PET. In the peripheral zone, the AUC of 0.893 for the PETMR model was significantly greater (p = 0.0402) than the AUC of 0.84 for the MR model only. In the whole prostate, no relevant correlation was observed between ADC and SUVmax. The SUVmax was not affected by the Gleason score. Conclusion: The performance of a hybrid whole-body 18F-fluorocholine PET/MRI scan in the same session combined with a prostatic MR examination did not interfere with the diagnostic accuracy of the MR sequences. The registration of the PET data and the T2 anatomical MR sequence data allowed precise localization of hypermetabolic foci in the prostate. While in the transition zone the adenomatous hyperplasia interfered with cancer detection by PET, the quantitative analysis tool performed well for cancer detection in the peripheral zone

Surgical therapy of thymic tumours with pleural involvement: an ESTS Thymic Working Group Project

OBJECTIVES Surgery for thymic epithelial tumours (TETs) with pleural involvement is infrequently performed. Thus, the value of surgical therapy for primary or recurrent TETs with pleural involvement is not sufficiently defined yet. METHODS Twelve institutions contributed retrospective data on 152 patients undergoing surgery (1977-2014) on behalf of the ESTS Thymic Working group. Outcome measures included overall (OS), cause-specific (CSS) and disease-free (DFS) survival as well as freedom from recurrence (FFR). RESULTS In 70.4% of cases, pleural involvement was present at the time of primary intervention, whereas 29.6% had surgery for recurrent disease involving the pleura. Pleural involvement resulted from thymomas (88.8%) and thymic carcinomas (11.2%). Forty extrapleural pneumonectomies (EPPs), 23 total pleurectomies (TPs), and 88 local pleurectomies (LPs) were performed (completeness of resection in 76.8%). OS for the entire patient population at 1, 3, 5 and 10 years was 96.4%, 91.0%, 87.2% and 62.7%, respectively. There was no statistically significant difference regarding FFR and OS for patients with local or advanced disease undergoing EPP, TP or LP. Thymic carcinomas in comparison with thymomas had a negative impact on OS [hazard ratio 6.506, P  = 0.002], CSS and FFR. Incomplete resections predicted worse OS [hazard ratio 6.696, P  = 0.003]. CONCLUSIONS Complete resection remains the mainstay of treatment for TETs with pleural involvement. Study populations treated with EPP, TP and LP had similar survival that may be factual as observed, but in the presence of selection bias, we can further conclude from the results that EPP, TP and LP are equally effective procedures. Procedural choice depends upon the extent of tumour distribution. EPPs, TPs and LPs performed within a multimodality setting seem to be efficient procedures for local control of disease, as they yield excellent results regarding OS, DFS, CSS and FFR

Calculation of The Band Gap Energy and Study of Cross Luminescence in Alkaline-Earth Dihalide Crystals

The band gap energy as well as the possibility of cross luminescence processes in alkaline-earth dihalide crystals have been calculated using the ab initio Perturbed-Ion (PI) model. The gap is calculated in several ways: as a difference between one-electron energy eigenvalues and as a difference between total energies of appropriate electronic states of the crystal, both at the HF level and with inclusion of Coulomb correlation effects. In order to study the possibility of ocurrence of cross luminescence in these materials, the energy difference between the valence band and the upmost core band for some representative crystals has been calculated. Both calculated band gap energies and cross luminescence predictions compare very well with the available experimental results.Comment: LaTeX file containing 8 pages plus 1 postscript figure. Final version accepted for publication in The Journal of the Physical Society of Japan. It contains a more complete list of references, as well as a more detailed comparison with previous theoretical investigations on the subjec