Αρχειοθήκη ιστολογίου

Αλέξανδρος Γ. Σφακιανάκης
ΩτοΡινοΛαρυγγολόγος
Αναπαύσεως 5
Άγιος Νικόλαος Κρήτη 72100
2841026182
6032607174

Πέμπτη 7 Ιουλίου 2022

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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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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Severity of SARS-CoV-2 Infection in Pregnancy

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Abstract
Background
Pregnancy represents a physiological state associated with increased vulnerability to severe outcomes from infectious diseases, both for the pregnant person and developing infant. The SARS-CoV-2 pandemic may have important health consequences for pregnant individuals, who may also be more reluctant than non-pregnant people to accept vaccination.
Methods
We sought to estimate the degree to which increased severity of SARS-CoV-2 outcomes can be attributed to pregnancy using a population-based SARS-CoV-2 case file from Ontario, Canada. Due to varying propensity to receive vaccination, and changes in dominant circulating viral strains over time, a time-matched cohort study was performed to evaluate the relative risk of severe illness in pregnant women with SARS-CoV-2 compared to other SARS-CoV-2 infected women of childbearing age (10 to 49 years old). Risk of severe SARS-CoV-2 outcomes was evaluated in pregnant women and time-matched non-pregnant controls using multivariable conditional logistic regression.
Results
Compared to the rest of the population, non-pregnant women of childbearing age had an elevated risk of infection (standardized morbidity ratio (SMR) 1.28), while risk of infection was reduced among pregnant women (SMR 0.43). After adjustment for confounding pregnant women had a markedly elevated risk of hospitalization (adjusted OR 4.96, 95% CI 3.86 to 6.37) and ICU admission (adjusted OR 6.58, 95% CI 3.29 to 13.18). The relative increase in hospitalization risk associated with pregnancy was greater in women without comorbidities than in those with comorbidities (P for heterogeneity 0.004).
Conclusions
Given the safety of SARS-CoV-2 vaccines in pregnancy, risk-benefit calculus strongly favours SARS-CoV-2 vaccination in pregnant women.
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Exploring the impact of anterior chest wall scars from implantable venous ports in adolescent survivors of cancer

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Abstract

Background

In children with cancer, port-a-caths (ports) are commonly placed in the right anterior chest wall, leaving a visible scar when removed. The psychological impact of port scars on survivors is unknown. It is unclear whether alternative sites should be considered. We assessed the impact of port scars on pediatric cancer survivors to determine whether a change in location is indicated.

Methods

We performed a cross-sectional single-center study of pediatric cancer survivors aged 13–18 years. A questionnaire explored participants' perceptions of their port scars. Four additional validated tools were used: Fitzpatrick scale, Patient and Observer Scar Assessment Scale (POSAS), Children's Dermatology Life Quality Index, and a Distress Thermometer.

Results

Among 100 participants (median age 15.8 years [13–18], median duration since treatment 8 years [1.5–14.8]), 75 'never/occasionally' thought about their port scars, 85 were not bothered by its location and 87 would not have preferred another site. Eleven participants were highly impacted by their scars: six thought about their scar 'everyday/all the time', four were highly bothered by its location, and nine would have preferred a different location. There was an association between the desire for different scar location and how much the location bothered participants (p < 0.0001), female sex (p = 0.03) and Patient POSAS score (p = 0.04).

Conclusion

A port scar on the anterior chest wall was not a major concern for the majority of this cohort. A minority of participants were highly impacted by the scar and its location. Advance identification of those likely to be impacted by their scars may not be possible.

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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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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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