k-Space Deep Learning for Reference-free EPI Ghost Correction

Nyquist ghost artifacts in EPI are originated from phase mismatch between the even and odd echoes. However, conventional correction methods using reference scans often produce erroneous results especially in high-field MRI due to the non-linear and time-varying local magnetic field changes. Recently, it was shown that the problem of ghost correction can be reformulated as k-space interpolation problem that can be solved using structured low-rank Hankel matrix approaches. Another recent work showed that data driven Hankel matrix decomposition can be reformulated to exhibit similar structures as deep convolutional neural network. By synergistically combining these findings, we propose a k-space deep learning approach that immediately corrects the phase mismatch without a reference scan in both accelerated and non-accelerated EPI acquisitions. To take advantage of the even and odd-phase directional redundancy, the k-space data is divided into two channels configured with even and odd phase encodings. The redundancies between coils are also exploited by stacking the multi-coil k-space data into additional input channels. Then, our k-space ghost correction network is trained to learn the interpolation kernel to estimate the missing virtual k-space data. For the accelerated EPI data, the same neural network is trained to directly estimate the interpolation kernels for missing k-space data from both ghost and subsampling. Reconstruction results using 3T and 7T in-vivo data showed that the proposed method outperformed the image quality compared to the existing methods, and the computing time is much faster.The proposed k-space deep learning for EPI ghost correction is highly robust and fast, and can be combined with acceleration, so that it can be used as a promising correction tool for high-field MRI without changing the current acquisition protocol.Comment: To appear in Magnetic Resonance in Medicin

Cell-free synthesis of functional phospholipase A1 from Serratia sp.

Additional file 1: Figure S1 Gas chromatography analysis of sesame oil incubated with cell-free synthesized PLA1

Effects of Rating Training on Inter-Rater Consistency for Developing a Dental Hygiene Clinical Rater Qualification System

We tried to develop itemized evaluation criteria and a clinical rater qualification system through rating training of inter-rater consistency for experienced clinical dental hygienists and dental hygiene clinical educators. A total of 15 clinical dental hygienists with 1-year careers participated as clinical examination candidates, while 5 dental hygienists with 3-year educations and clinical careers or longer participated as clinical raters. They all took the clinical examination as examinees. The results were compared, and the consistency of competence was measured. The comparison of clinical competence between candidates and clinical raters showed that the candidate group's mean clinical competence ranged from 2.96 to 3.55 on a 5-point system in a total of 3 instruments (Probe, Explorer, Curet), while the clinical rater group's mean clinical competence ranged from 4.05 to 4.29. There was a higher inter-rater consistency after education of raters in the following 4 items: Probe, Explorer, Curet, and insertion on distal surface. The mean score distribution of clinical raters ranged from 75% to 100%, which was more uniform in the competence to detect an artificial calculus than that of candidates (25% to 100%). According to the above results, there was a necessity in the operating clinical rater qualification system for comprehensive dental hygiene clinicians. Furthermore, in order to execute the clinical rater qualification system, it will be necessary to keep conducting a series of studies on educational content, time, frequency, and educator level

Incidences of Waterborne and Foodborne Diseases After Meteorologic Disasters in South Korea

BackgroundClimate change could increase the number of regions affected by meteorologic disasters. Meteorologic disasters can increase the risk of infectious disease outbreaks, including waterborne and foodborne diseases. Although many outbreaks of waterborne diseases after single disasters have been analyzed, there have not been sufficient studies reporting comprehensive analyses of cases occurring during long-term surveillance after multiple disasters, which could provide evidence of whether meteorologic disasters cause infectious disease outbreaks.ObjectivesThis study aimed to assess the nationwide short-term changes in waterborne and foodborne disease incidences after a meteorologic disaster.MethodsWe analyzed cases after all 65 floods and typhoons between 2001 and 2009 using the Korean National Emergency Management Agency's reports. Based on these data, we compared the weekly incidences of 'Vibrio vulnificus' septicemia (VVS), shigellosis, typhoid fever, and paratyphoid fever before, during, and after the disasters, using multivariate Poisson regression models. We also analyzed the interactions between disaster characteristics and the relative risk of each disease.FindingsCompared with predisaster incidences, the incidences of VVS and shigellosis were 2.49-fold (95% confidence interval, 1.47-4.22) and 3.10-fold (95% confidence interval, 1.21-7.92) higher, respectively, the second week after the disaster. The incidences of VVS and shigellosis peaked the second week postdisaster and subsequently decreased. The risks of typhoid and paratyphoid fever did not significantly increase throughout the 4 weeks postdisaster. The daily average precipitation interacted with VVS and shigellosis incidences, whereas disaster type only interacted with VVS incidence patterns.ConclusionsThe incidences of VVS and shigellosis were associated with meteorologic disasters, and disaster characteristics were associated with the disease incidence patterns postdisaster. These findings provide important comprehensive evidence to develop and support policies for managing and protecting public health after meteorologic disasters

Decreased health-related quality of life in disease-free survivors of differentiated thyroid cancer in Korea

<p>Abstract</p> <p>Background</p> <p>Concern regarding the health-related quality of life (HRQOL) of long-term survivors of thyroid cancer has risen due to the rapid increase in the incidence of thyroid cancer, which generally has an excellent prognosis. The aim of this study was to evaluate the status of HRQOL in disease-free survivors of differentiated thyroid carcinoma (DTC) and to evaluate the important determinants of HRQOL.</p> <p>Methods</p> <p>This was a cross-sectional study in which we interviewed consecutive disease-free survivors of DTC. Three different validated questionnaires ("EORTC QLQ-C30" for various functional domains, the "brief fatigue inventory (BFI)" and the "hospital anxiety and depression scale" (HADS)) were used. Data from a large, population based survey of 1,000 people were used as a control.</p> <p>Results</p> <p>The response rate for the questionnaires was 78.9% (316/401). Disease-free survivors of DTC showed a decreased HRQOL in all five functional domains (physical, role, cognitive, emotional, and social) on the EORTC QLQ-C30 compared with controls (<it>P </it>< 0.01). BFI and HADS-anxiety scores also showed greater distress in disease-free survivors of DTC than in controls (<it>P </it>< 0.05). A multiple regression analysis for the determinants of HRQOL showed that the HADS-anxiety, HADS-depression, and BFI scores were the most significant components of decreased HRQOL.</p> <p>Conclusions</p> <p>Although disease-free survivors of DTC are expected to have disease-specific survival comparable to the general population, they experience a significantly decreased HRQOL. Anxiety, depression, and fatigue were the major determinants of the decreased HRQOL. Supportive psychological care should be integrated into the management of long-term survivors of DTC.</p

Clinical features of adolescents with suicide attempt and the factors associated with their outcomes: poisoning versus non-poisoning

Purpose Methods for suicide attempt are largely divided into poisoning and non-poisoning, which differ in clinical features and severity. We aimed to investigate the clinical features of adolescents with suicide attempt and factors associated with poor outcomes from the 2 methods. Methods A retrospective study was conducted on adolescents (10-18 years) who visited the emergency department after suicide attempt from 2011 through 2018. The adolescents were divided into the poisoning and non-poisoning groups. We analyzed the differences of clinical features and outcomes between the 2 groups. Poor outcomes were defined as hospitalization to the intensive care unit or death. Factors associated with poor outcomes were investigated using multivariable logistic regression. Results Of 4,335 adolescents in total, 2,134 (49.2%) were categorized as the poisoning group. In this group, the adolescents with poor outcomes used acetaminophen most frequently (26.5%), followed by sedative or antipsychotics (22.3%). In the non-poisoning group, those with the outcomes used fall from height (73.2%) most commonly, followed by hanging (21.0%). The factors associated with the outcomes were age (for increment of 1 year; odds ratio, 1.11; 95% confidence interval, 1.02-1.22) in the poisoning group, and being boys (1.34; 1.03-1.73) and non-use of alcohols (2.87; 1.73-4.74) in the non-poisoning group. Conclusion In adolescents who used poisoning for suicide attempt, increasing age is associated with poor outcomes. The outcomes are associated with being boys and non-use of alcohols in those who used non-poisoning methods

Age group characteristics of children who visited a regional trauma center and analysis of factors affecting the severe trauma

Purpose The aim of this study was to analyze the age group characteristics and factors associated with the severe trauma in children who visited a regional trauma center. Methods We reviewed children aged 18 years or younger who visited a regional trauma center, equivalent to level 1 trauma centers in the United States, in Incheon, Korea from July 2014 through December 2019. They were classified by the age groups: preschoolers (0-6 years), schoolers (7-12 years), and adolescents (13-18 years). Across the 3 age groups, event profiles, severity, and outcomes of injury were compared. Multivariable logistic regressions were used to identify factors associated with the severe trauma, defined as the Injury Severity Score of 16 or higher. Results Among the total of 367 children, 74 (20.2%) were preschoolers, 73 (19.9%) were schoolers, and 220 (59.9%) were adolescents. The most common injury mechanisms in the preschoolers, schoolers, and adolescents were fall (40.5%), pedestrian collision (32.9%), and motorcycle accident (38.6%), respectively. The adolescents had the highest median Injury Severity Score (13 [interquartile range, 6-23]; P < 0.001). In the multivariable analyses, the Glasgow Coma Scale of 3-8 (odds ratio [OR], 14.60; 95% confidence interval, 5.40-39.42) had the highest OR for severe trauma, followed by injury in the abdomen or pelvic contents (OR, 11.61; 95% confidence interval, 4.66-28.89). Conclusion In pediatric trauma, the mechanism and severity of injury may differ according to age groups, with the severe trauma associated with injuries to the head and torso. It is advisable to have age group-specific approaches and strategies for injury prevention