scholarly journals Perfusion imaging of neuroblastoma and nephroblastoma in a paediatric population using pseudo-continuous arterial spin-labelling magnetic resonance imaging

2021 ◽  
Author(s):  
Anita Adriaantje Harteveld ◽  
Annemieke Simone Littooij ◽  
Max Maria van Noesel ◽  
Marijn van Stralen ◽  
Clemens Bos
Keyword(s):  
Contrast Enhancement ◽  
Region Of Interest ◽  
Paediatric Population ◽  
Data Sets ◽  
Visual Evaluation ◽  
Contralateral Kidney ◽  
Paediatric Patients ◽  
Study Population ◽  
Perfusion Measurements ◽  
Abdominal Tumours

Abstract Objectives To examine the feasibility of performing ASL-MRI in paediatric patients with solid abdominal tumours. Methods Multi-delay ASL data sets were acquired in ten paediatric patients diagnosed with either a neuroblastoma (n = 4) or nephroblastoma (n = 6) during a diagnostic MRI examination at a single visit (n = 4 at initial staging, n = 2 neuroblastoma and n = 2 nephroblastoma patients; n = 6 during follow-up, n = 2 neuroblastoma and n = 4 nephroblastoma patients). Visual evaluation and region-of-interest (ROI) analyses were performed on the processed perfusion-weighted images to assess ASL perfusion signal dynamics in the whole tumour, contralateral kidney, and tumour sub-regions with/without contrast enhancement. Results The majority of the included abdominal tumours presented with relatively low perfusion-weighted signal (PWS), especially compared with the highly perfused kidneys. Within the tumours, regions with high PWS were observed which, at short PLD, are possibly related to labelled blood inside vessels and at long PLD, reflect labelled blood accumulating inside tumour tissue over time. Conversely, comparison of ASL perfusion-weighted image findings with T1w enhancement after contrast administration showed that regions lacking contrast enhancement also were void of PWS. Discussion This pilot study demonstrates the feasibility of utilizing ASL-MRI in paediatric patients with solid abdominal tumours and provides a basis for further research on non-invasive perfusion measurements in this study population.

Localizing the Accessory Pathway in Ventricular Preexcitation Patients Using a Score Based Algorithm

2012 ◽  
Vol 51 (01) ◽  
pp. 3-12 ◽  
Author(s):  
M. C. Stühlinger ◽  
C. N. Nowak ◽  
K. Spuller ◽  
K. Etsadashvili ◽  
X. Stühlinger ◽  
...  
Keyword(s):  
Cardiac Electrophysiology ◽  
Accessory Pathway ◽  
Positive Likelihood Ratio ◽  
Original Study ◽  
Data Sets ◽  
Standardized Residuals ◽  
Study Population ◽  
A Prospective Study ◽  
Ventricular Preexcitation ◽  
Better Than

SummaryObjectives: Clinical data was analyzed to find an efficient way to localize the accessory pathway in patients with ventricular preexcitation.Methods: The delta wave morphologies and ablation sites of 186 patients who underwent catheter ablation were analyzed and an algorithm (“locAP”) to localize the accessory pathway was developed from the 84 data sets with a PQ interval ≤ 0.12 s and a QRS width ≥ 0.12 s. Fifty additional patients were included for a prospective validation. The locAP algorithm ranks 13 locations according to the likelihood that the accessory pathway is localized there. The algorithm is based on the locAP score which uses the standardized residuals of the available data sets.Results: The locAP algorithm’s accuracy is 0.54 for 13 locations, with a sensitivity of 0.84, a specificity of 0.97, and a positive likelihood ratio of 24.94. If the two most likely locations are regarded, the accuracy rises to 0.79, for the three most likely locations combined the accuracy is 0.82. This new algorithm performs better than Milstein’s, Fitzpatrick’s, and Arruda’s algorithm both in the original study population as well as in a prospective study.Conclusions: The locAP algorithm is a valid and valuable tool for clinical practice in a cardiac electrophysiology laboratory. It could be shown that use of the locAP algorithm is favorable over the localizing algorithms that are in clinical use today.

scholarly journals Challenges in UAS-Based TIR Imagery Processing: Image Alignment and Uncertainty Quantification

2020 ◽  
Vol 12 (10) ◽  
pp. 1552 ◽  
Author(s):  
Veronika Döpper ◽  
Tobias Gränzig ◽  
Birgit Kleinschmit ◽  
Michael Förster
Keyword(s):  
Land Cover ◽  
Contrast Enhancement ◽  
Camera Calibration ◽  
Weather Conditions ◽  
Thermal Infrared ◽  
Temperature Correction ◽  
Image Alignment ◽  
Data Sets ◽  
Image Contrast Enhancement ◽  
The Impact

Thermal infrared measurements acquired with unmanned aerial systems (UAS) allow for high spatial resolution and flexibility in the time of image acquisition to assess ground surface temperature. Nevertheless, thermal infrared cameras mounted on UAS suffer from low radiometric accuracy as well as low image resolution and contrast hampering image alignment. Our analysis aims to determine the impact of the sun elevation angle (SEA), weather conditions, land cover, image contrast enhancement, geometric camera calibration, and inclusion of yaw angle information and generic and reference pre-selection methods on the point cloud and number of aligned images generated by Agisoft Metashape. We, therefore, use a total amount of 56 single data sets acquired on different days, times of day, weather conditions, and land cover types. Furthermore, we assess camera noise and the effect of temperature correction based on air temperature using features extracted by structure from motion. The study shows for the first time generalizable implications on thermal infrared image acquisitions and presents an approach to perform the analysis with a quality measure of inter-image sensor noise. Better image alignment is reached for conditions of high contrast such as clear weather conditions and high SEA. Alignment can be improved by applying a contrast enhancement and choosing both, reference and generic pre-selection. Grassland areas are best alignable, followed by cropland and forests. Geometric camera calibration hampers feature detection and matching. Temperature correction shows no effect on radiometric camera uncertainty. Based on a valid statistical analysis of the acquired data sets, we derive general suggestions for the planning of a successful field campaign as well as recommendations for a suitable preprocessing workflow.

scholarly journals Developing Gridded Climate Data Sets of Precipitation for Greece Based on Homogenized Time Series

Climate ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 68 ◽  
Author(s):  
Flora Gofa ◽  
Anna Mamara ◽  
Manolis Anadranistakis ◽  
Helena Flocas
Keyword(s):  
Climate Model ◽  
Interpolation Method ◽  
Region Of Interest ◽  
Data Sets ◽  
Monthly Precipitation ◽  
Climate Data ◽  
Variable Nature ◽  
Wide Range ◽  
Realistic Representation ◽  
Space Data

The creation of realistic gridded precipitation fields improves our understanding of the observed climate and is necessary for validating climate model output for a wide range of applications. The challenge in trying to represent the highly variable nature of precipitation is to overcome the lack of density of observations in both time and space. Data sets of mean monthly and annual precipitations were developed for Greece in gridded format with an analysis of 30 arcsec (∼800 m) based on data from 1971 to 2000. One hundred and fifty-seven surface stations from two different observation networks were used to cover a satisfactory range of elevations. Station data were homogenized and subjected to quality control to represent changes in meteorological conditions rather than changes in the conditions under which the observations were made. The Meteorological Interpolation based on Surface Homogenized Data Basis (MISH) interpolation method was used to develop data sets that reproduce, as closely as possible, the spatial climate patterns over the region of interest. The main geophysical factors considered for the interpolation of mean monthly precipitation fields were elevation, latitude, incoming solar irradiance, Euclidian distance from the coastline, and land-to-sea percentage. Low precipitation interpolation uncertainties estimated with the cross-validation method provided confidence in the interpolation method. The resulting high-resolution maps give an overall realistic representation of precipitation, especially in fall and winter, with a clear longitudinal dependence on precipitation decreasing from western to eastern continental Greece.

scholarly journals Understanding the characteristics of recurrent visits to the emergency department by paediatric patients: a retrospective observational study conducted at three tertiary hospitals in Korea

BMJ Open ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. e018208 ◽  
Author(s):  
Byung-Soo Kim ◽  
Jung-Youn Kim ◽  
Sung-Hyuk Choi ◽  
Young-Hoon Yoon
Keyword(s):  
Emergency Department ◽  
Observational Study ◽  
Medical Condition ◽  
Paediatric Population ◽  
Retrospective Observational Study ◽  
Main Diagnosis ◽  
Paediatric Patients ◽  
Common Diagnosis ◽  
The Usa ◽  
Ed Visits

ObjectivesThe number of paediatric patients visiting the emergency department (ED) continues to rise. In South Korea, approximately 25% of the patients who visit the ED are paediatric patients. In the USA, about 20% of the paediatric population were found to have visited the ED in the past year. A recent study demonstrated that 4.5%–8% of patients account for 25% of all ED visits. Therefore, the aim of this study was to identify the characteristics of recurrent visits.MethodsDesign: retrospective observational study. Setting: this study examined and analysed medical record data involving three tertiary EDs. Participants: a total of 46 237 ED visits by patients <16 years during 1-year period. Main outcome measures: data collected included the number of recurrent ED patients, frequency of recurrent visits, age, sex, insurance status, period until recurrent visit (days), main diagnosis and ED discharge results.ResultsExcluding patients with multiple visits, the total number of paediatric patients who fit the study criteria was 33 765. Among these patients, 23 384 (69.2%) had no recurrent ED visits in the subsequent year after their first visit. A total of 15 849 (46.8%) patients were toddlers (between age 1 and 4 years). In the patient group without a recurrent visit, fever was the most common diagnosis.ConclusionsOur study reviewed medical records to inspect the characteristics of patients who return to care. Higher recurrent visit frequency was associated with using the 119 rescue centre service, having a medical condition, with younger age and a higher rate of hospitalisation. Analysis of the factors associated with frequent ED visits will help to improve care for paediatric patients who visit the ED.

scholarly journals Increasing incidence of anaphylaxis in Hong Kong from 2009 to 2019—discrepancies of anaphylaxis care between adult and paediatric patients

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Philip Hei Li ◽  
Agnes S. Y. Leung ◽  
Rebecca M. Y. Li ◽  
Ting-fan Leung ◽  
Chak-sing Lau ◽  
...  
Keyword(s):  
Hong Kong ◽  
Incidence Rate ◽  
Developed Countries ◽  
Paediatric Population ◽  
Incidence Rates ◽  
Published Data ◽  
The Past ◽  
Paediatric Patients ◽  
Increasing Trend ◽  
Prescription Rates

Abstract Background Anaphylaxis has been increasing in developed countries but there is very little published data on the burden of anaphylaxis and the pattern of adrenaline autoinjector (AAI) prescription from Asia. We aim to determine the incidence rates of anaphylaxis and prescription rates of AAI over the past decade in Hong Kong. Methods Using a centralized electronic database of Hong Kong’s sole public-funded healthcare provider, we obtained and analysed all patients between 2009 and 2019 with physician-reported diagnosis of anaphylaxis. Incidence rates were calculated using population statistics as the denominator. Patients’ prescriptions on discharge were collected to determine the AAI prescription rates. Results The overall 10-year estimated incidence rate of anaphylaxis was 3.57 per 100,000 person-years. An increasing trend over time across both paediatric and adult populations from 2009 to 2014 was found, which remained stable until 2019. This was more marked among the paediatric population (paediatric vs adult incidence rate ratio in 2019: 3.51 [95% CI 1.12–2.66] vs 1.82 [95% CI 1.05–1.60]). There was an overall increasing rate of AAI prescription for patients admitted for anaphylaxis, but the overall AAI prescription rate was less than 15% and was significantly less likely to be prescribed for the adult compared to paediatric patients (36.5% vs. 89.4%, p < 0.001). Conclusions An increasing trend of anaphylaxis incidence rates over the past decade is evident in Asian populations, with a discrepantly low rate of AAI prescription, particularly in the adult patients.

scholarly journals THE USEFULNESS OF DEAMIDATED GLIADIN PEPTIDE IN SCREENING PEDIATRIC PATIENTS FOR CELIAC DISEASE

2018 ◽  
Vol 23 (suppl_1) ◽  
pp. e14-e14
Author(s):  
Michelle Gould ◽  
Herbert Brill ◽  
Margaret Marcon ◽  
Catharine Walsh
Keyword(s):  
Celiac Disease ◽  
Positive Predictive Value ◽  
Predictive Value ◽  
Tissue Transglutaminase ◽  
Paediatric Population ◽  
Iga Deficiency ◽  
Additional Patient ◽  
Serologic Marker ◽  
Paediatric Patients ◽  
Gliadin Peptide

Abstract BACKGROUND Celiac disease (CD) is an autoimmune enteropathy triggered by gliadin. The gold standard for diagnosis is small bowel biopsy. Screening with serologic markers to identify endoscopic candidates is commonly completed by paediatricians. The most common serologic marker used for screening is IgA anti-Tissue Transglutaminase (TTG) antibodies. Antibodies to deamidated gliadin peptide (DGP) is a newer assay with studies demonstrating a diagnostic performance similar to anti-TTG. In Canada, this assay has been added to many laboratory’s celiac screening panels. There is little evidence however regarding the usefulness of an isolated positive anti-DGP result in paediatric patients and no study has systematically assessed the presence of biopsy proven CD in solely anti-DGP positive paediatric patients. OBJECTIVES We sought to determine the positive predictive value of anti-DGP for biopsy proven CD in paediatric patients with negative TTG IgA testing. DESIGN/METHODS A multi-center retrospective review of children referred to three centers in Ontario, Canada between January 2015 and December 2016 who had isolated anti-IgG DGP positive CD serology was completed. To be included, patients required serology positive for DGP IgG and negative for all other celiac serologic tests, as well as a duodenal biopsy while on a gluten-containing diet. The positive predictive value of isolated anti-DGP was calculated. RESULTS A total of 83 patients were identified with anti-DGP positive, anti-TTG negative serology. Of these, 40 patients underwent endoscopy. Only 1 patient had findings consistent with CD on biopsy (Marsh 3B histology), yielding a positive predictive value of 2.5%. This patient was IgA deficient. Amongst the cohort of IgA sufficient patients (N=25), the positive predictive value of anti-DGP serology was 0%. One additional patient who was IgA sufficient had findings in keeping with Marsh 2 histology, but repeat TTG and DGP testing was negative. Five patients were found to be IgA deficient at the time of serologic testing, 25 were IgA sufficient and 10 did not have a measured IgA. CONCLUSION Isolated positive DGP IgG serology has a poor positive predictive value for CD, especially in IgA sufficient individuals. For this reason, DGP IgG testing should not be completed as part of the initial screening for celiac disease in the paediatric population unless a compelling reason, such as IgA deficiency or age under 2 years, is present, in order to prevent unnecessary invasive follow-up testing and costs to patients and the health care system.

scholarly journals Patient reported disability of ankle, hindfoot, midfoot and hallux metatarsophalangeal arthritis

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0001
Author(s):  
Matthew Christian ◽  
Clifford Jeng ◽  
Rebecca Cerrato ◽  
John T. Campbell ◽  
Scott Koenig ◽  
...  
Keyword(s):  
Rating Scales ◽  
Short Form ◽  
High Volume ◽  
Data Sets ◽  
Foot And Ankle ◽  
Operative Techniques ◽  
Ankle Arthritis ◽  
Patient Reported ◽  
Study Population ◽  
Component Scores

Category: Ankle, Ankle Arthritis, Hindfoot, Midfoot/Forefoot Introduction/Purpose: There has been in increased interest in foot and ankle arthritis in the literature in recent years. A significant focus of the literature has been which operative techniques are best for managing these problems. Some work has been done analogizing disability due to ankle arthritis to more familiar joints such as the hip. There is little data explaining how much patient reported disability is associated with each type of isolated foot and ankle arthritis. Various clinical rating scales have proven how debilitating foot and ankle arthritides can be to patients. The purpose of our study was to use Functional Foot Index (FFI) and Short Form-12 (SF-12) rating scales to compare the patient reported disability associated with ankle, hindfoot, midfoot, and hallux metatarsalphalangeal (MTP) arthritides. Methods: We retrospectively reviewed the FFI and SF-12 (both Physical Component Scores (PCS) and Mental Component Scores (MCS)) of patients who presented to a high volume orthopaedic foot and ankle practice between 2010 and 2016 with either ankle, hindfoot, midfoot or hallux MTP arthritis. We included patients between 18-65 years of age who underwent a surgical procedure for arthritis within 6 months of their initial presentation. We excluded patients with any medical or surgical co-morbidities known to affect disability scores. A total of 214 FFI and 195 SF-12 data sets were included. Results: Study population SF-12 PCS scores for all patients with ankle or foot arthritis were significantly lower than US age-based norms. Patients with ankle arthritis had the highest disability (FFI score 46.5, SF-12 PCS 32.3). Patients with midfoot and hindfoot arthritis had intermediate disability (Midfoot FFI score 34.9, SF-12 PCS 34.5; Hindfoot FFI score 44.3, SF-12 PCS 34.5). Patients with hallux MTP arthritis had the lowest disability (FFI score 32.9, SF-12 PCS 40.7). All FFI and SF-12 PCS scores were statistically significant. SF 12 MCS were not statistically significant. Conclusion: All patients with foot and ankle arthritis had increased disability compared to US age-based norms. Patients with ankle arthritis experience the most self-reported disability and patients with hallux MTP arthritis experience the least self- reported disability of the isolated types of arthritis in orthopaedic foot and ankle.

Electromagnetic traveltime tomography: Application for reservoir characterization in the Lost Hills oil field, California

Geophysics ◽  
2005 ◽  
Vol 70 (3) ◽  
pp. G51-G58 ◽  
Author(s):  
Tae Jong Lee ◽  
Toshihiro Uchida
Keyword(s):  
Reservoir Characterization ◽  
Fresnel Zone ◽  
Region Of Interest ◽  
Oil Field ◽  
Data Sets ◽  
Traveltime Tomography ◽  
Conductivity Structure ◽  
Before And After ◽  
Conductivity Image ◽  
Induction Logs

Electromagnetic (EM) traveltime tomography has been applied for reservoir characterization at the Lost Hills oil field, California. Four data sets at frequencies of 24, 90, 370, and 1000 Hz were obtained along a pair of monitoring boreholes located 80.5 m apart. Traveltime information was first extracted from these EM data sets using a wavefield transform with a ray series approximation. The conductivity contrast of each layer is no greater than two in the region of interest, so the first arrivals can be estimated within 5% error by the approximate scheme. A nonlinear traveltime tomography algorithm adopting a Fresnel zone concept was then applied to obtain the conductivity model between the boreholes. The resultant conductivity image represents the conductivity structure between the boreholes. This image is consistent with the results of both a finite-difference inversion and the induction log obtained prior to waterflooding. Comparing the two conductivity images with the induction logs, we observe major differences in the fracture-dominant resistive reservoir layer, which may have been caused by changes in reservoir condition before and after waterflooding.

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