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Πέμπτη 7 Ιουλίου 2022

Automated Detection, Segmentation, and Classification of Pleural Effusion From Computed Tomography Scans Using Machine Learning

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imageObjective This study trained and evaluated algorithms to detect, segment, and classify simple and complex pleural effusions on computed tomography (CT) scans. Materials and Methods For detection and segmentation, we randomly selected 160 chest CT scans out of all consecutive patients (January 2016–January 2021, n = 2659) with reported pleural effusion. Effusions were manually segmented and a negative cohort of chest CTs from 160 patients without effusions was added. A deep convolutional neural network (nnU-Net) was trained and cross-validated (n = 224; 70%) for segmentation and tested on a separate subset (n = 96; 30%) with the same distribution of reported pleural complexity features as in the training cohort (eg, hyperdense fluid, gas, pleural thickening and loculation). On a separate consecutive cohort with a high prevalence of pleural complexity features (n = 335), a random forest model was implemented for classification of segmented effusions with Hounsfield unit thresholds, density distribution, and radiomics-based features as input. As performance measures, sensitivity, specificity, and area under the curves (AUCs) for detection/classifier evaluation ( per-case level) and Dice coefficient and volume analysis for the segmentation task were used. Results Sensitivity and specificity for detection of effusion were excellent at 0.99 and 0.98, respectively (n = 96; AUC, 0.996, test data). Segmentation was robust (median Dice, 0.89; median absolute volume difference, 13 mL), irrespective of size, complexity, or contrast phase. The sensitivity, specificity, and AUC for classification in simple versus complex effusions were 0.67, 0.75, and 0.77, respectively. Conclusion Using a dataset with different degrees of complexity, a robust model was developed for the detection, segmentation, and classification of effusion subtypes. The algorithms are openly available at https://github.com/usb-radiology/pleuraleffusion.git.
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New-Generation Low-Field Magnetic Resonance Imaging of Hip Arthroplasty Implants

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imageObjectives Despite significant progress, artifact-free visualization of the bone and soft tissues around hip arthroplasty implants remains an unmet clinical need. New-generation low-field magnetic resonance imaging (MRI) systems now include slice encoding for metal artifact correction (SEMAC), which may result in smaller metallic artifacts and better image quality than standard-of-care 1.5 T MRI. This study aims to assess the feasibility of SEMAC on a new-generation 0.55 T system, optimize the pulse protocol parameters, and compare the results with those of a standard-of-care 1.5 T MRI. Materials and Methods Titanium (Ti) and cobalt-chromium total hip arthroplasty implants embedded in a tissue-mimicking American Society for Testing and Materials gel phantom were evaluated using turbo spin echo, view angle tilting (VAT), and combined VAT and SEMAC (VAT + SEMAC) pulse sequences. To refine an MRI protocol at 0.55 T, the type of metal artifact reduction techniques and the effect of various pulse sequence parameters on metal artifacts were assessed through qualitative ranking of the images by 3 expert readers while taking measured spatial resolution, signal-to-noise ratios, and acquisition times into consideration. Signal-to-noise ratio efficiency and artifact size of the optimized 0.55 T protocols were compared with the 1.5 T standard and compressed-sensing SEMAC sequences. Results Overall, the VAT + SEMAC sequence with at least 6 SEMAC encoding steps for Ti and 9 for cobalt-chromium implants was ranked higher than other sequences for metal reduction (P
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Pharmacokinetics, Safety, and Efficacy of Gadopiclenol in Pediatric Patients Aged 2 to 17 Years

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imageObjectives The aim of this study was to evaluate the pharmacokinetic (PK) profile, safety, and efficacy of gadopiclenol, a new high-relaxivity gadolinium-based contrast agent, in children aged 2 to 17 years. Materials and Methods Children scheduled to undergo contrast-enhanced magnetic resonance imaging of the central nervous system (CNS cohort) or other organs (body cohort) were included sequentially into 3 age groups (12–17, 7–11, and 2–6 years). Gadopiclenol was administered at the dose of 0.05 mmol/kg. A sparse sampling approach was applied, with 4 blood samples per child collected up to 8 hours postinjection. Population PK modeling was used for the analysis, including the CNS cohort and adult subjects from a previous study. Adverse events were recorded, and efficacy was assessed for all children. Results Eighty children were included, 60 in the CNS cohort and 20 in the body cohort. The 2-compartment model with linear elimination from the central compartment developed in adults was also suitable for children. Pharmacokinetic parameters were very similar between adults and children. Terminal elimination half-life was 1.82 hours for adults and 1.77 to 1.29 hours for age groups 12–17 to 2–6 years. The median clearance ranged from 0.08 L/h/kg in adults and 12–17 years to 0.12 L/h/kg in 2–6 years. The median central and peripheral volumes of distribution were 0.11 to 0.12 L/kg and 0.06 L/kg, respectively, for both adults and children. Simulations of plasma concentrations showed minor differences, and median area under the curve was 590 mg·h/L for adults and 582 to 403 mg·h/L for children. Two patients (2.5%) experienced nonserious adverse events considered related to gadopiclenol: a mild QT interval prolongation and a moderate maculopapular rash. Despite the limited number of pat ients, this study showed that gadopiclenol improved lesion detection, visualization, and diagnostic confidence. Conclusions The PK profile of gadopiclenol in children aged 2 to 17 years was similar to that observed in adults. Thus, there is no indication for age-based dose adaptation, and comparable plasma gadopiclenol concentrations are predicted to be achieved with body weight–based dosing in this population. Gadopiclenol at 0.05 mmol/kg seems to have a good safety profile in these patients and could improve lesion detection and visualization, therefore providing better diagnostic confidence.
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Antibody and T-cell responses 6 months after COVID-19 mRNA-1273 vaccination in patients with chronic kidney disease, on dialysis, or living with a kidney transplant

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Abstract
Background
The immune response to COVID-19 vaccination is inferior in kidney transplant recipients (KTR), and to a lesser extent in patients on dialysis or with chronic kidney disease (CKD). We assessed the immune response 6 months after mRNA-1273 vaccination in kidney patients and compared this to controls.
Methods
152 participants with CKD stages G4/5 (eGFR <30  mL/min/1.73m2), 145 participants on dialysis, 267 KTR, and 181 controls were included. SARS-CoV-2 Spike S1-specific IgG antibodies were measured by fluorescent bead-based multiplex-immunoassay, neutralizing antibodies to ancestral, Delta and Omicron (BA.1) variants by plaque reduction, and T-cell responses by IFN-γ release assay.
Results
At 6 months after vaccination S1-specific antibodies were detected in 100% of controls, 98.7% of CKD G4/5 patients, 95.1% of dialysis patients, and 56.6% of KTR. These figures were comparable to the respons e rates at 28 days, but antibody levels waned significantly. Neutralization of the ancestral and Delta variant was detected in most participants, whereas neutralization of Omicron was mostly absent. S-specific T-cell responses were detected 6 months in 75.0% of controls, 69.4% of CKD G4/5 patients, 52.6% of dialysis patients, and 12.9% of KTR. T-cell responses at 6 months were significantly lower than responses at 28 days.
Conclusions
Although seropositivity rates at 6 months were comparable to that at 28 days after vaccination, significantly decreased antibody levels and T-cell responses were observed. The combination of low antibody levels, reduced T-cell responses, and absent neutralization of the newly-emerging variants indicates the need for additional boosts or alternative vaccination strategies in KTR.
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Strategies for Evaluating Anosmia Therapeutics in the COVID-19 Era

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jamanetwork.com

Two studies in this issue of JAMA Otolaryngology–Head & Neck Surgery evaluate the use of nasal theophylline, a phosphodiesterase inhibitor that may promote neural olfactory signaling and recovery for postviral olfactory dysfunction (OD). The first, a dose-modification Research Letter by Lee et al was conducted in patients with non-COVID-19–related hyposmia or anosmia secondary to viral infection and confirmed by the objective University of Pennsylvania Smell Identification Test. This open-label, dose-escalation trial provides an educational description of how to evaluate the appropriate dose for an emerging pharmacologic intervention. Specifically, the authors identified 400 mg of theophylline twice daily as a tolerated dosage. This was calculated as an equivalent oral dose of 20 mg. A phase 2 pilot study by Gupta et al was desig ned using this valuable information. Patients with suspected COVID-19–related OD completed the University of Pennsylvania Smell Identification Test and were randomized to either theophylline or placebo nasal irrigations for 6 weeks. This study was inconclusive regarding the clinical benefit of theophylline nasal irrigations, although there was suggested improvement by subjective assessments. The authors acknowledge several limitations, including small sample size, the virtual nature of the study design and subsequent inability to conduct endoscopic nasal examinations, lack of information regarding participant COVID-19 vaccination status, lack of polymerase chain reaction–confirmed COVID-19 infection, and short-term participant follow-up. These acknowledgments are justified, and many can be overcome in subsequent studies with adequate funding and time. However, the heterogeneous nature of COVID-19 and associated research make this area of work particularly challenging. Herein, we propose several approaches to improve the rigor of OD research in the COVID-19 era.
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Efficacy and Safety of Saline Nasal Irrigation Plus Theophylline for COVID-19–Related Olfactory Dysfunction

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This randomized clinical trial evaluates the efficacy and safety of theophylline added to saline nasal irrigation compared with placebo for COVID-19–related olfactory dysfunction.
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Safety of High-Dose Nasal Theophylline Irrigation in the Treatment of Postviral Olfactory Dysfunction

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This case series aims to determine the maximum tolerable dose of theophylline delivered via high-volume, low-pressure nasal saline irrigation for treatment of postviral olfactory dysfunction.
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Surgeon Thyroidectomy Case Volume Impacts Disease‐free Survival in the Management of Thyroid Cancer

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Surgeon Thyroidectomy Case Volume Impacts Disease-free Survival in the Management of Thyroid Cancer

In this population-based cohort study involving 37,233 thyroidectomies performed in Ontario, Canada between 1993 and 2017, we found both high-volume surgeons and hospitals to be predictors of better disease-free survival (DFS) in patients with well-differentiated thyroid cancer. DFS is higher among surgeons performing more than 40 thyroidectomies a year.


Objectives

To assess the association between surgeons thyroidectomy case volume and disease-free survival (DFS) for patients with well-differentiated thyroid cancer (WDTC). A secondary objective was to assess a surgeon volume cutoff to optimize outcomes in those with WDTC. We hypothesized that surgeon volume will be an important predictor of DFS in patients with WDTC after adjusting for hospital volume and sociodemographic and clinical factors.

Methods

In this retrospective population-based cohort study, we identified WDTC patients in Ontario, Canada, who underwent thyroidectomy confirmed by both hospital-level and surgeon-level administrative data between 1993 and 2017 (N = 37,233). Surgeon and hospital volumes were calculated based on number of cases performed in the year prior by the physician and at an institution performing each case, respectively and divided into quartiles. A multilevel hierarchical Cox regression model was used to estimate the effect of volume on DFS.

Results

A crude model without patient or treatment characteristics demonstrated that both higher surgeon volume quartiles (p < 0.001) and higher hospital volume quartiles (p < 0.001) were associated with DFS. After controlling for clustering and patient/treatment covariates and hospital volume, moderately low (18–39/year) and low (0–17/year) volume surgeons (hazard ratios [HR]: 1.23, 95% confidence interval [CI]: 1.09–1.39 and HR: 1.34, 95% CI: 1.17–1.53 respectively) remained an independent statistically significant negative predictor of DFS.

Conclusion

Both high-volume surgeons and hospitals are predictors of better DFS in patients with WDTC. DFS is higher among surgeons performing more than 40 thyroidectomies a year.

Level of Evidence

3 Laryngoscope, 2022

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Tooth Preservation vs. Extraction and Implant Placement in Periodontally Compromised Patients: A Systematic Review and Analysis of Studies

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Abstract

Purpose

: The aim of this systematic review was to identify studies with a minimum of 5-years follow-up, reporting on the management of periodontally compromised teeth with either extraction and subsequent implant placement or teeth preservation with conventional periodontal treatment and application of regenerative procedures. The outcomes of these two approaches, based on clinical and radiographic data and the incidence of tooth- and implant-loss, were also investigated.

Material and methods

: A systematic search for studies reporting on clinical and radiographic outcomes of periodontal treatment or replacement of periodontally compromised teeth with implants was conducted in 3 electronic databases, followed by a hand-search in 8 journals. Only randomized controlled trials (RCTs), cohort studies, and case series with prospective design were included.

Results

: The initial search resulted in 1080 papers. After the first two screenings, 24 publications were selected for inclusion in this systematic review. The treatment protocols for the teeth preservation group contained non-surgical and/or surgical periodontal treatment with or without regeneration procedures. The implant studies included extraction of periodontally involved teeth and implant placement with or without bone and soft tissue augmentation, followed by restoration with fixed dental prostheses (FDPs). Survival rates ranged between 81.8% and 100% in the tooth retention group, and between 94.8% and 100% in the implant group. In the extraction group, no complications were reported for 76.09% of the implants. Similarly, no complications were reported for 86.83% of the tooth retention group. The lack of standardized comparable studies prohibited conduction of a meta-analysis.

Conclusion

: Both treatment approaches, treatment of periodontally compromised teeth, or tooth extraction followed by implant placement, present high survival rates. The application of bone regeneration techniques improves the long-term prognosis of periodontally involved teeth. Hence, treatment of periodontally involved teeth with subsequent application of a rigorous maintenance protocol can be a viable alternative for a number of years, before proceeding to extraction and replacement with dental implants. More well-designed randomized controlled trials are needed in order to draw definite conclusions on the subject.

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