This work aims to characterize the novel DRX Plus 3543C detector in terms of detective quantum efficiency (DQE) using both a mobile x-ray system called Carestream DRX Revolution Nano and a ...traditional x-ray system (Carestream DRX Evolution). We used the commercial system DRX Revolution Nano, equipped with a new x-ray source based on CNT technology and field emission (FE) as the electron emitter (cathode). An innovative aspect of this device is its intrinsic selection of the focal spot size. We tested the system using three IEC-specified beam qualities (RQA3, 5 and 7) in terms of modulation transfer function (MTF), normalized noise power spectra (NNPS) and DQE as defined in the IEC 62220-1-1:2015. We compared the results obtained using DRX Revolution Nano and DRX Evolution with correlation and with Bland-Altman plots to study their agreement. RQA3 MTF is slightly lower than the RQA5 and 7 curves between 0.5 and 2.5 cycles mm−1. We measured MTF values of about 0.6 at 1 lp mm−1 and about 0.28 lp mm−1 at 2 lp mm−1. The NNPS curves show a decreasing trend with the energy regarding the DRX Revolution Nano. On the other hand, the DRX Evolution NNPS curve at RQA3 is greater than the one at RQA5, but the one at RQA5 is less than the one at RQA7. The DQE(0) ranged between about 0.82 (DRX Evolution at RQA3) and 0.54 (DRX Evolution at RQA7). As expected, the squared Pearson's correlation coefficients between the two x-ray tubes were always in an optimal agreement, and Bland-Altman plots confirmed a substantial equivalence between the two physical characterizations of the wireless detector. In conclusion, we can show that the dynamic focal selection of the system equipped with CNT does not play a substantial role in image quality compared to a traditional system in terms of physical characterisation of the detector in our measurement conditions.
Hybrid conformal field theories Bertolini, Marco; Melnikov, Ilarion V.; Plesser, M. Ronen
The journal of high energy physics,
05/2014, Letnik:
2014, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
We describe a class of (2,2) superconformal field theories obtained by fibering a Landau-Ginzburg orbifold CFT over a compact Kähler base manifold. While such models are naturally obtained ...as phases in a gauged linear sigma model, our construction is independent of such an embedding. We discuss the general properties of such theories and present a technique to study the massless spectrum of the associated heterotic compactification. We test the validity of our method by applying it to hybrid phases of linear models and comparing spectra among the phases.
The settlement of Verucchio rises on an Apennine cliff from which a ford of the river Marecchia to the north-west and a good part of the Adriatic coast to the east could be controlled, not far from ...Mount Titano that stands a few km south-east in a dominant position (Figure 1).
While for decades research was devoted to the famous necropolis of the Early Iron Age located at the steep sides of the plateau, for the settlement of Verucchio only synthetic reports of late-nineteenth century and preliminary news of some excavations conducted in the Sixties and Seventies of the last century
Objective and design
We aimed to identify cytokines whose concentrations are related to lung damage, radiomic features, and clinical outcomes in COVID-19 patients.
Material or subjects
Two hundred ...twenty-six patients with SARS-CoV-2 infection and chest computed tomography (CT) images were enrolled.
Methods
CCL18, CHI3L1/YKL-40, GAL3, ANG2, IP-10, IL-10, TNFα, IL-6, soluble gp130, soluble IL-6R were quantified in plasma samples using Luminex assays. The Mann–Whitney
U
test, the Kruskal–Wallis test, correlation and regression analyses were performed. Mediation analyses were used to investigate the possible causal relationships between cytokines, lung damage, and outcomes. AVIEW lung cancer screening software, pyradiomics, and XGBoost classifier were used for radiomic feature analyses.
Results
CCL18, CHI3L1, and ANG2 systemic levels mainly reflected the extent of lung injury. Increased levels of every cytokine, but particularly of IL-6, were associated with the three outcomes: hospitalization, mechanical ventilation, and death. Soluble IL-6R showed a slight protective effect on death. The effect of age on COVID-19 outcomes was partially mediated by cytokine levels, while CT scores considerably mediated the effect of cytokine levels on outcomes. Radiomic-feature-based models confirmed the association between lung imaging characteristics and CCL18 and CHI3L1.
Conclusion
Data suggest a causal link between cytokines (risk factor), lung damage (mediator), and COVID-19 outcomes.
The analyses here reported aim to compare the screening performance of digital tomosynthesis (DBT) versus mammography (DM).
MAITA is a consortium of four Italian trials, REtomo, Proteus, Impeto, and ...MAITA trial. The trials adopted a two-arm randomised design comparing DBT plus DM (REtomo and Proteus) or synthetic-2D (Impeto and MAITA trial) versus DM; multiple vendors were included. Women aged 45 to 69 years were individually randomised to one round of DBT or DM.
From March 2014 to February 2022, 50,856 and 63,295 women were randomised to the DBT and DM arm, respectively. In the DBT arm, 6656 women were screened with DBT plus synthetic-2D. Recall was higher in the DBT arm (5·84% versus 4·96%), with differences between centres. With DBT, 0·8/1000 (95% CI 0·3 to 1·3) more women received surgical treatment for a benign lesion. The detection rate was 51% higher with DBT, ie. 2·6/1000 (95% CI 1·7 to 3·6) more cancers detected, with a similar relative increase for invasive cancers and ductal carcinoma in situ. The results were similar below and over the age of 50, at first and subsequent rounds, and with DBT plus DM and DBT plus synthetic-2D. No learning curve was appreciable. Detection of cancers >= 20 mm, with 2 or more positive lymph nodes, grade III, HER2-positive, or triple-negative was similar in the two arms.
Results from MAITA confirm that DBT is superior to DM for the detection of cancers, with a possible increase in recall rate. DBT performance in screening should be assessed locally while waiting for long-term follow-up results on the impact of advanced cancer incidence.
•MAITA is a population-based, multicentre, and multivendor consortium of trials.•DBT plus DM or plus s2D is superior to DM alone in detecting invasive cancers.•We did not observe any overall decrease in recall rate•Differences between centres in recall ranged from no effect to +50% in DBT vs. DM.•Our results impose to assess locally the impact of DBT in screening.
•Multicentric physical and dosimetric characterisation of 4 different CEDM systems.•First measurements of the IMS-Giotto Class CEDM system are reported in this work.•Iodine quantification in CEDM on ...a dedicated phantom.
Contrast-enhanced digital mammography (CEDM) is a relatively new imaging technique recombining low- and high-energy mammograms to emphasise iodine contrast. This work aims to perform a multicentric physical and dosimetric characterisation of four state-of-the-art CEDM systems.
We evaluated tube output, half-value-layer (HVL) for low- and high-energy and average glandular dose (AGD) in a wide range of equivalent breast thicknesses. CIRS phantom 022 was used to estimate the overall performance of a CEDM examination in the subtracted image in terms of the iodine difference signal (S). To calculate dosimetric impact of CEDM examination, we collected 4542 acquisitions on patients.
Even if CEDM acquisition strategies differ, all the systems presented a linear behaviour between S and iodine concentration. The curve fit slopes expressed in PV/mg/cm2 were in the range 92–97 for Fujifilm, 31–32 for GE Healthcare, 35–36 for Hologic, and 114–130 for IMS. Dosimetric data from patients were matched with AGD values calculated using equivalent PMMA thicknesses. Fujifilm exhibited the lowest values, while GE Healthcare showed the highest.
The subtracted image showed the ability of all the systems to give important information about the linearity of the signal with the iodine concentrations. All the patient-collected doses were under the AGD EUREF 2D Acceptable limit, except for patients with thicknesses ≤35 mm belonging to GE Healthcare and Hologic, which were slightly over. This work demonstrates the importance of testing each CEDM system to know how it performs regarding dose and the relationship between PV and iodine concentration.
Background
To verify the long-term (24-week) efficacy, safety, and tolerability of fremanezumab in real-life patients with high-frequency episodic migraine (HFEM: ≥ 8 days/month) or chronic migraine ...(CM: ≥ 15 days/month), and multiple preventive treatment failures.
Methods
This is a prospective, cohort, real-life study at 28 headache centers on consecutive patients affected by HFEM or CM with multiple preventive treatment failures who were prescribed subcutaneous fremanezumab (225 mg monthly/675 mg quarterly) for ≥ 24 weeks. Primary endpoint was the change in monthly migraine days (MMDs) in HFEM and monthly headache days (MHDs) in CM at weeks 21–24 compared to baseline. Secondary endpoints encompassed changes in monthly analgesic medications, ≥ 50%, ≥ 75%, and 100% responder rates, and variation in NRS, HIT-6 and MIDAS scores at the same time interval. Changes in MMDs/MHDs, monthly analgesic medications, ≥ 50%, ≥ 75%, and 100% responder rates, and variation in NRS and HIT-6 scores at week 4 were also monitored.
Results
Four hundred ten patients who had received ≥ 1 dose of fremanezumab were considered for safety analysis while 148 patients treated for ≥ 24 weeks were included in the efficacy analysis. At weeks 21–24, fremanezumab significantly (
p
< 0.001) reduced MMDs, MHDs, monthly analgesic medications and NRS, HIT-6, and MIDAS scores in both HFEM and CM compared to baseline. The proportions of ≥ 50%, ≥ 75% and 100% responders at weeks 21-24were 75.0%, 30.8%, 9.6% (HFEM), and 72.9, 44.8 and 1% (CM). A significant (
p
< 0.001) decrease in MMDs, MHDs, monthly analgesic medications and NRS, HIT-6, and MIDAS scores in both HFEM and CM was already present at week 4. The proportions of ≥ 50%, ≥ 75%, and 100% responders at week 4 were 67.6%, 32.4%, 11.8% (HFEM) and 67.3%, 40%, 1.8% (CM). CM remitted to episodic migraine and medication overuse to no-medication overuse in 83.3 and 75% of patients at week 24, and in 80 and 72.4% at week 4. Adverse events were rare (2.4%), mild and transient. No patient discontinued treatment for any reason.
Conclusions
Fremanezumab is characterized by an early and sustained efficacy in HFEM and CM patients with multiple preventive treatment failures in real-life, revealing an optimal safety and tolerability profile.
Objectives
Tomosynthesis (DBT) has proven to be more sensitive than digital mammography, but it requires longer reading time. We retrospectively compared accuracy and reading times of a simplified ...protocol with 1-cm-thick slabs versus a standard protocol of slabs + 1-mm-spaced planes, both integrated with synthetic 2D.
Methods
We randomly selected 894 DBTs (including 12 cancers) from the experimental arm of the RETomo trial. DBTs were read by two radiologists to estimate specificity. A second set of 24 cancers (8 also present in the first set) mixed within 276 negative DBTs was read by two radiologists. In total, 28 cancers with 64 readings were used to estimate sensitivity. Radiologists read with both protocols separated by a 3-month washout. Only women that were positive at the screening reading were assessed. Variance was estimated taking into account repeated measures.
Results
Sensitivity was 82.8% (53/64, 95% confidence interval (95% CI) 67.2–92.2) and 90.6% (95% CI 80.2–95.8) with simplified and standard protocols, respectively. In the random screening setting, specificity was 97.9% (1727/1764, 95% CI 97.1–98.5) and 96.3% (95% CI 95.3–97.1), respectively. Inter-reader agreement was 0.68 and 0.54 with simplified and standard protocols, respectively. Median reading times with simplified protocol were 20% to 30% shorter than with standard protocol.
Conclusions
A simplified protocol reduced reading time and false positives but may have a negative impact on sensitivity.
Key Points
• The adoption of digital breast tomosynthesis (DBT) in screening, more sensitive than mammography, could be limited by its potential effect on the radiologists’ workload, i.e., increased reading time and fatigue.
• A DBT simplified protocol with slab only, compared to a standard protocol (slab plus planes) both integrated with synthetic 2D, reduced time and false positives but had a negative impact on sensitivity.
Objective: Interstitial fibrosis/tubular atrophy (IFTA) is a common, irreversible, and progressive form of chronic kidney allograft injury, and it is considered a critical predictor of kidney ...allograft outcomes. The extent of IFTA is estimated through a graft biopsy, while a non-invasive test is lacking. The aim of this study was to evaluate the feasibility and accuracy of an MRI radiomic-based machine learning (ML) algorithm to estimate the degree of IFTA in a cohort of transplanted patients. Approach: Patients who underwent MRI and renal biopsy within a 6-month interval from 1 January 2012 to 1 March 2021 were included. Stable MRI sequences were selected, and renal parenchyma, renal cortex and medulla were segmented. After image filtering and pre-processing, we computed radiomic features that were subsequently selected through a LASSO algorithm for their highest correlation with the outcome and lowest intercorrelation. Selected features and relevant patients’ clinical data were used to produce ML algorithms using 70% of the study cases for feature selection, model training and validation with a 10-fold cross-validation, and 30% for model testing. Performances were evaluated using AUC with 95% confidence interval. Main results: A total of 70 coupled tests (63 patients, 35.4% females, mean age 52.2 years) were included and subdivided into a wider cohort of 50 for training and a smaller cohort of 20 for testing. For IFTA ≥ 25%, the AUCs in test cohort were 0.60, 0.59, and 0.54 for radiomic features only, clinical variables only, and a combined radiomic–clinical model, respectively. For IFTA ≥ 50%, the AUCs in training cohort were 0.89, 0.84, and 0.96, and in the test cohort, they were 0.82, 0.83, and 0.86, for radiomic features only, clinical variables only, and the combined radiomic–clinical model, respectively. Significance: An ML-based MRI radiomic algorithm showed promising discrimination capacity for IFTA > 50%, especially when combined with clinical variables. These results need to be confirmed in larger cohorts.
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