Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 28
Filter
1.
J Surg Educ ; 80(11): 1693-1702, 2023 11.
Article in English | MEDLINE | ID: mdl-37821350

ABSTRACT

OBJECTIVE: As the American Board of Surgery transitions to a competency-based model of surgical education centered upon entrustable professional activities (EPAs), there is a growing need for objective tools to determine readiness for entrustment. This study evaluates the usability of ENTRUST, an innovative virtual patient simulation platform to assess surgical trainees' decision-making skills in preoperative, intra-operative, and post-operative settings. DESIGN: This is a mixed-methods analysis of the usability of the ENTRUST platform. Quantitative data was collected using the system usability scale (SUS) and Likert responses. Analysis was performed with descriptive statistics, bivariate analysis, and multivariable linear regression. Qualitative analysis of open-ended responses was performed using the Nielsen-Shneiderman Heuristics framework. SETTING: This study was conducted at an academic institution in a proctored exam setting. PARTICIPANTS: The analysis includes n = 47 (PGY 1-5) surgical residents who completed an online usability survey following the ENTRUST Inguinal Hernia EPA Assessment. RESULTS: The ENTRUST platform had a median SUS score of 82.5. On bivariate and multivariate analyses, there were no significant differences between usability based on demographic characteristics (all p > 0.05), and SUS score was independent of ENTRUST performance (r = 0.198, p = 0.18). Most participants agreed that the clinical workup of the patient was engaging (91.5%) and felt realistic (85.1%). The most frequent heuristics represented in the qualitative analysis included feedback, visibility, match, and control. Additional themes of educational value, enjoyment, and ease-of-use highlighted participants' perspectives on the usability of ENTRUST. CONCLUSIONS: ENTRUST demonstrates high usability in this population. Usability was independent of ENTRUST score performance and there were no differences in usability identified in this analysis based on demographic subgroups. Qualitative analysis highlighted the acceptability of ENTRUST and will inform ongoing development of the platform. The ENTRUST platform holds potential as a tool for the assessment of EPAs in surgical residency programs.


Subject(s)
Clinical Competence , Internship and Residency , Humans , Curriculum , Competency-Based Education/methods , Educational Measurement
2.
J Grad Med Educ ; 15(2): 228-236, 2023 Apr.
Article in English | MEDLINE | ID: mdl-37139206

ABSTRACT

Background: As entrustable professional activities (EPAs) are implemented in graduate medical education, there is a great need for tools to efficiently and objectively evaluate clinical competence. Readiness for entrustment in surgery requires not only assessment of technical ability, but also the critical skill of clinical decision-making. Objective: We report the development of ENTRUST, a serious game-based, virtual patient case creation and simulation platform to assess trainees' decision-making competence. A case scenario and corresponding scoring algorithm for the Inguinal Hernia EPA was iteratively developed and aligned with the description and essential functions outlined by the American Board of Surgery. In this study we report preliminary feasibility data and validity evidence. Methods: In January 2021, the case scenario was deployed and piloted on ENTRUST with 19 participants of varying surgical expertise levels to demonstrate proof of concept and initial validity evidence. Total score, preoperative sub-score, and intraoperative sub-score were analyzed by training level and years of medical experience using Spearman rank correlations. Participants completed a Likert scale user acceptance survey (1=strongly agree to 7=strongly disagree). Results: Median total score and intraoperative mode sub-score were higher with each progressive level of training (rho=0.79, P<.001 and rho=0.69, P=.001, respectively). There were significant correlations between performance and years of medical experience for total score (rho=0.82, P<.001) and intraoperative sub-scores (rho=0.70, P<.001). Participants reported high levels of platform engagement (mean 2.06) and ease of use (mean 1.88). Conclusions: Our study demonstrates feasibility and early validity evidence for ENTRUST as an assessment platform for clinical decision-making.


Subject(s)
Internship and Residency , Humans , Education, Medical, Graduate , Competency-Based Education , Clinical Competence , Clinical Decision-Making
3.
J Surg Educ ; 79(6): e202-e212, 2022.
Article in English | MEDLINE | ID: mdl-35909070

ABSTRACT

OBJECTIVE: As the American Board of Surgery (ABS) moves toward implementation of Entrustable Professional Activities (EPAs), there is a growing need for objective evaluation of readiness for entrustment of residents. This requires not only assessment of technical skills and knowledge, but also surgical decision-making in preoperative, intraoperative, and postoperative settings. We developed and piloted an Inguinal Hernia EPA Assessment on ENTRUST, a serious game-based online virtual patient simulation platform to assess trainees' decision-making competence. DESIGN: This is a prospective analysis of resident performance on the ENTRUST Inguinal Hernia EPA Assessment using bivariate analyses. SETTING: This study was conducted at an academic institution in a proctored exam setting. PARTICIPANTS: Forty-three surgical residents completed the ENTRUST Inguinal Hernia EPA Assessment. RESULTS: Four case scenarios for the Inguinal Hernia EPA and corresponding scoring algorithms were iteratively developed by expert consensus aligned with ABS EPA descriptions and functions. ENTRUST Inguinal Hernia Grand Total Score was positively correlated with PGY-level (p < 0.0001). Preoperative, Intraoperative, and Postoperative Total Scores were also positively correlated with PGY-level (p = 0.001, p = 0.006, and p = 0.038, respectively). Total Case Scores were positively correlated with PGY-level for cases representing elective unilateral inguinal hernia (p = 0.0004), strangulated inguinal hernia (p < 0.0001), and elective bilateral inguinal hernia (p = 0.0003). Preoperative Sub-Scores were positively correlated with PGY-level for all cases (p < 0.01). Intraoperative Sub-Scores were positively correlated with PGY-level for strangulated inguinal hernia and bilateral inguinal hernia (p = 0.0007 and p = 0.0002, respectively). Grand Total Score and Intraoperative Sub-Score were correlated with prior operative experience (p < 0.0001). Prior video game experience did not correlate with performance on ENTRUST (p = 0.56). CONCLUSIONS: Performance on the ENTRUST Inguinal Hernia EPA Assessment was positively correlated to PGY-level and prior inguinal hernia operative performance, providing initial validity evidence for its use as an objective assessment for surgical decision-making. The ENTRUST platform holds potential as tool for assessment of ABS EPAs in surgical residency programs.


Subject(s)
Hernia, Inguinal , Internship and Residency , Humans , United States , Hernia, Inguinal/surgery , Clinical Competence
4.
Children (Basel) ; 9(2)2022 Feb 06.
Article in English | MEDLINE | ID: mdl-35204926

ABSTRACT

Identifying ischemic ovary as a complication of ovary torsion (OT) is a significant challenge in children. This study identified risk factors for ischemic OT among pediatric OT patients to prevent delayed treatment. This retrospective study included pediatric inpatients who underwent operation for OT over 20 years. We employed multivariable logistic regression to find the risk factors associated with ischemic OT. Among the 118 patients included in this study, 78 (66.1%) had ischemic OT. Patients with ischemic OT tended to be younger; had more frequent vomiting; and had elevated White blood cell (WBC), C-Reactive protein (CRP), and segments in comparison with non-ischemic OT patients. Multivariable regression showed increased odds of ischemic ovary torsion, associated with higher WBC (12.3 × 103/mm3 vs. 8.7 × 103/mm3, p < 0.001), CRP (50.4 mg/L vs. 8.4 mg/L, p < 0.001), and vomiting (55.1% vs. 25%, p = 0.002) than in non-ischemic patients. A receiver-operating characteristic (ROC) analysis indicated that patients with vomiting, leukocytosis, or CRP ≧ 40 mg/L were more likely to have ischemic OT (sensitivity, 92%; specificity, 54%; PPV, 79.6; NPV, 78.9%). Ischemic OT is common among pediatric OT patients. The presence of potential risk factors of vomiting, leukocytosis, and CRP more significant than 40 mg/L may assist clinicians in ensuring an expedited surgical treatment.

5.
Stem Cell Res ; 49: 102029, 2020 12.
Article in English | MEDLINE | ID: mdl-33096384

ABSTRACT

Type 1 diabetes (T1D) is characterized by the autoimmune destruction of insulin-producing ß cells. Genetic studies have identified > 60 T1D risk loci that harbor genes with disease-causative alleles. However, determining the biological effects of such loci is often difficult due to limited tissue availability. Disease-specific human induced pluripotent stem cells (hiPSCs) are a valuable resource for modeling T1D pathogenesis. In particular, families with complete disease penetrance offer an opportunity to further dissect T1D risk loci. Here, we describe the generation of three hiPSC lines from a T1D family with sequence variants associated with autoimmunity.


Subject(s)
Diabetes Mellitus, Type 1 , Induced Pluripotent Stem Cells , Insulin-Secreting Cells , Alleles , Autoimmunity/genetics , Diabetes Mellitus, Type 1/genetics , Humans
6.
Ann Vasc Surg ; 66: 671.e1-671.e4, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32027984

ABSTRACT

Light-induced amaurosis is a rare manifestation of symptomatic carotid artery disease. Unlike amaurosis fugax, which is often attributed to embolic phenomenon associated with carotid artery disease, light-induced amaurosis has been associated with reduced perfusion to the eye, secondary to carotid artery disease, leading to retinal ischemia. The case described here is that of a 67-year-old male with bilateral vision loss in response to bright light. Imaging revealed severe internal carotid stenosis on the right and occlusion of the internal carotid artery on the left. Similar to previous cases reported in the literature, the symptoms resolved after carotid endarterectomy.


Subject(s)
Blindness/etiology , Carotid Artery, Internal , Carotid Stenosis/complications , Light/adverse effects , Aged , Blindness/diagnosis , Blindness/physiopathology , Carotid Artery, Internal/diagnostic imaging , Carotid Artery, Internal/surgery , Carotid Stenosis/diagnostic imaging , Carotid Stenosis/surgery , Endarterectomy, Carotid , Humans , Male , Recovery of Function , Severity of Illness Index , Treatment Outcome , Vision, Ocular , Visual Perception
7.
Pediatr Radiol ; 50(5): 689-697, 2020 05.
Article in English | MEDLINE | ID: mdl-31993707

ABSTRACT

BACKGROUND: Gastric emptying scintigraphy is widely used in infants and children, but there is a lack of age-specific normative data. OBJECTIVE: The objectives of this retrospective study were: 1) to establish a range of gastric emptying of milk or formula as a surrogate for normal gastric emptying in infants and young children ≤5 years of age, and 2) to investigate the effects of patient age, feeding volume, feeding route and gastroesophageal reflux on gastric emptying. MATERIALS AND METHODS: The reports of 5,136 gastric emptying studies of children ≤5 years of age performed at Children's National Medical Center from January 1990 to August 2012 were reviewed. Demographic data, 1-h and 3-h gastric emptying values and gastroesophageal reflux status of all patients were stored in a database. Using stringent inclusion and exclusion criteria, the studies of patients as similar to healthy children as possible were selected for this study. RESULTS: The study group included 2,273 children (57% male) ages 0-59 months (median: 4.6 months). The median 1-h gastric emptying was 43% (interquartile range [IQR] 34-54%). The median 3-h gastric emptying was 91% (IQR 79-98%). Sixty-one percent of patients with 1-h gastric emptying value of <50% had 3-h gastric emptying ≥80%. Gastric emptying was significantly faster in children ≤6 months as compared with all older age groups. In each age group, the median gastric emptying decreased with increasing feeding volume. Gastric emptying was significantly faster in patients fed via combined nasogastric tube and oral routes as compared with those fed exclusively orally. There was no significant difference in gastric emptying of children with and without gastroesophageal reflux. CONCLUSION: Although there are statistically significant differences in gastric emptying based on age, volume and route of feeding, the data suggest that overall normal liquid gastric emptying in infants and children ≤5 years of age is ≥80% at 3 h. One-hour emptying measurements are not reliable for detecting delayed gastric emptying.


Subject(s)
Gastric Emptying/physiology , Milk , Stomach/diagnostic imaging , Stomach/physiology , Age Factors , Animals , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Radionuclide Imaging/methods , Retrospective Studies
8.
Int J Paleopathol ; 21: 138-146, 2018 06.
Article in English | MEDLINE | ID: mdl-29778411

ABSTRACT

We present a rare case of primary bone cancer principally affecting the right humerus of a skeleton from the pre-Columbian site of Cerro Brujo (1265-1380 CE) in Bocas del Toro, on the Caribbean coast of Panamá, excavated in the early 1970s. The humerus contains a dense, calcified sclerotic mass with associated lytic lesions localized around the midshaft of the diaphysis. Evidence of systemic inflammation and anemia, likely caused by the cancer, are visible in the form of severe porotic hyperostosis of the cranial vault and bilateral periosteal reactions in the tibiae. Differential diagnosis and future probes of the tumor are discussed. A tooth from the individual yielded a radiocarbon date 150 years later than those of the domestic occupation at the site. Given that it was the only formal burial recovered from the site, and as the individual had such a visible, painful, and rare pathology, this likely constitutes a ritual burial.


Subject(s)
Bone Neoplasms/history , Bone Neoplasms/pathology , Humerus/pathology , Adolescent , History, Ancient , Humans , Panama
9.
IEEE Trans Cybern ; 47(9): 2862-2871, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28113536

ABSTRACT

An evolutionary fuzzy block-matching-based image denoising algorithm is proposed to remove noise from a camera raw image. Recently, a variance stabilization transform is widely used to stabilize the noise variance, so that a Gaussian denoising algorithm can be used to remove the signal-dependent noise in camera sensors. However, in the stabilized domain, the existed denoising algorithm may blur too much detail. To provide a better estimate of the noise-free signal, a new block-matching approach is proposed to find similar blocks by the use of a type-2 fuzzy logic system (FLS). Then, these similar blocks are averaged with the weightings which are determined by the FLS. Finally, an efficient differential evolution is used to further improve the performance of the proposed denoising algorithm. The experimental results show that the proposed denoising algorithm effectively improves the performance of image denoising. Furthermore, the average performance of the proposed method is better than those of two state-of-the-art image denoising algorithms in subjective and objective measures.

10.
Eur J Nucl Med Mol Imaging ; 43(4): 663-74, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26519293

ABSTRACT

PURPOSE: Small-cell cervical cancer (SCCC) is rare and prone to metastasize. We conducted a prospective study to evaluate the role of (18)F-FDG PET in the management of this aggressive malignancy. METHODS: Patients with untreated primary, histologically confirmed SCCC were enrolled. (18)F-FDG PET (or PET/CT) was performed immediately after MRI or CT, for primary staging, monitoring response to treatment or restaging when there was suspicion of recurrence. The clinical impact of PET was determined on a scan basis. RESULTS: A total of 25 patients were recruited and 43 PET scans were performed. The PET images were obtained for primary staging (25 patients), monitoring response (10 patients) and restaging when there was suspicion of recurrence (8 patients). The median follow-up time in event-free patients was 109.3 months (range 97.5 - 157.7 months). A positive impact of PET was found in 8 (18.6 %) of the 43 scans, which included detection of additional regions of distal lymph node (LN) metastasis (one primary staging scan, two restaging scans), bone metastasis (two primary staging scans, one monitoring response scan), and exclusion of false-positive lesions on MRI (one primary staging scan, one restaging scan). On the other hand, one negative impact was recorded as one false-positive lesion on a restaging PET scan. One positive impact was noted for monitoring response (bone metastasis). The impact of three scans was indeterminate. The positive impact of down-staging in avoiding overtreatment but finding additional distal LN (except one on restaging) or bone metastases had no beneficial effect on long-term survival. CONCLUSION: The results of this preliminary study suggest that PET is useful in the management of SCCC. PET could have more value in detecting occult metastases if future novel therapies are able to offer better control of extensive SCCC.


Subject(s)
Carcinoma, Small Cell/diagnostic imaging , Fluorodeoxyglucose F18 , Positron-Emission Tomography , Radiopharmaceuticals , Uterine Cervical Neoplasms/diagnostic imaging , Adult , Aged , Female , Humans , Middle Aged , Multimodal Imaging , Tomography, X-Ray Computed
11.
Pediatr Radiol ; 44(8): 1039-41, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24658375

ABSTRACT

All-trans retinoic acid (ATRA), a component of standard therapy for acute promyelocytic leukemia (APL), is associated with potentially serious but treatable adverse effects involving numerous organ systems, including rare skeletal muscle involvement. Only a handful of cases of ATRA-induced myositis in children have been reported, and none in the radiology literature. We present such a case in a 15-year-old boy with APL, where recognition of imaging findings played a crucial role in making the diagnosis and facilitated prompt, effective treatment.


Subject(s)
Antineoplastic Agents/adverse effects , Leukemia, Promyelocytic, Acute/drug therapy , Myositis/chemically induced , Myositis/diagnosis , Tretinoin/adverse effects , Adolescent , Antineoplastic Agents/therapeutic use , Contrast Media , Dexamethasone/therapeutic use , Diagnosis, Differential , Gadolinium , Glucocorticoids/therapeutic use , Humans , Image Enhancement/methods , Magnetic Resonance Imaging/methods , Male , Myositis/drug therapy , Thigh/pathology , Treatment Outcome , Tretinoin/therapeutic use
12.
ISA Trans ; 53(1): 56-75, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24012389

ABSTRACT

A modified nonlinear autoregressive moving average with exogenous inputs (NARMAX) model-based state-space self-tuner with fault tolerance is proposed in this paper for the unknown nonlinear stochastic hybrid system with a direct transmission matrix from input to output. Through the off-line observer/Kalman filter identification method, one has a good initial guess of modified NARMAX model to reduce the on-line system identification process time. Then, based on the modified NARMAX-based system identification, a corresponding adaptive digital control scheme is presented for the unknown continuous-time nonlinear system, with an input-output direct transmission term, which also has measurement and system noises and inaccessible system states. Besides, an effective state space self-turner with fault tolerance scheme is presented for the unknown multivariable stochastic system. A quantitative criterion is suggested by comparing the innovation process error estimated by the Kalman filter estimation algorithm, so that a weighting matrix resetting technique by adjusting and resetting the covariance matrices of parameter estimate obtained by the Kalman filter estimation algorithm is utilized to achieve the parameter estimation for faulty system recovery. Consequently, the proposed method can effectively cope with partially abrupt and/or gradual system faults and input failures by the fault detection.

13.
Radiol Clin North Am ; 51(4): 637-57, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23830790

ABSTRACT

Multidetector computed tomography (MDCT) offers an important noninvasive imaging modality for confirmation and further characterization of primary lung and large airway neoplasms encountered in pediatric patients. Children represent a unique challenge in imaging, not only because of unique patient factors (eg, inability to follow instructions, motion, need for sedation) but because of the technical factors that must be optimized to reduce radiation dose. This article reviews an MDCT imaging algorithm, up-to-date imaging techniques, and clinical applications of MDCT for evaluating benign and malignant primary neoplasms of lung and large airway in infants and children.


Subject(s)
Multidetector Computed Tomography , Respiratory Tract Neoplasms/diagnostic imaging , Algorithms , Carcinoid Tumor/diagnostic imaging , Carcinoma, Small Cell/diagnostic imaging , Child , Hamartoma/diagnostic imaging , Hemangioma/diagnostic imaging , Humans , Lung Neoplasms/diagnostic imaging , Multidetector Computed Tomography/methods , Papilloma/diagnostic imaging , Respiratory Tract Neoplasms/pathology
15.
Eur Arch Otorhinolaryngol ; 270(6): 1909-15, 2013 May.
Article in English | MEDLINE | ID: mdl-23188165

ABSTRACT

Unexpected fatal events in patients with head and neck cancers undergoing concurrent chemoradiation therapy are a clinical concern. Malnutrition, which is reported frequently in head and neck cancer patients, are associated with immunity derangement. The purpose of this study was to identify risk factors for early death of patients undergoing chemoradiation. We retrospectively analyzed the records of 194 stage III, IVA, and IVB head and neck cancer patients who were treated with chemoradiation between 2007 and 2009. We defined early death as death while receiving chemoradiation or within 60 days of treatment completion. Risk factors for early death were tested using univariate and multivariate analyses. Fourteen patients (7.2 %) experienced early death, 78.6 % of whom died of infection. Univariate analysis revealed significant correlations between early death and several pretreatment variables, including Eastern Cooperative Oncology Group performance status (PS) >1, hemoglobin <10 g/dL, albumin <3 g/dL, body mass index (BMI) <19 kg/m(2), and peripheral blood total lymphocyte count <700/µL. Multivariate analysis showed that PS >1, BMI <19 kg/m(2), and peripheral blood total lymphocyte count <700/µL were independent variables associated with early death. Poor performance status and malnutrition before chemoradiation independently predict early death in locally advanced head and neck cancer patients undergoing chemoradiation. Cautious management of head and neck cancer patients with these risk factors is required throughout chemoradiation period.


Subject(s)
Chemoradiotherapy , Head and Neck Neoplasms/mortality , Head and Neck Neoplasms/therapy , Nutritional Status , Adult , Aged , Aged, 80 and over , Female , Head and Neck Neoplasms/pathology , Humans , Male , Middle Aged , Neoplasm Staging , Retrospective Studies , Risk Factors , Treatment Outcome
16.
Laryngoscope ; 122(10): 2193-8, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22886710

ABSTRACT

OBJECTIVES/HYPOTHESIS: To investigate the association between body mass index and outcomes such as recurrence and survival in postoperative locally advanced oral cavity cancer patients who underwent adjuvant chemoradiation. STUDY DESIGN: Retrospective analysis of patient data and outcomes. METHODS: We retrospectively analyzed the records of 61 stage III, IVA, and IVB oral cavity cancer patients who were treated with curative surgery and adjuvant chemoradiation between 2007 and 2009. Each patient's body mass index was recorded throughout the treatment duration and after its completion. The associations between demographic variables, body mass index, and survival outcomes were determined by univariate and multivariate analyses. RESULTS: Overall, body mass index decreased throughout the chemoradiation period and reached the nadir at 3 months after completion of therapy. Univariate analysis showed that patients with body mass index <18.5 kg/m(2) at 3 months after chemoradiation had significantly higher recurrence and decreased survival rates. Multivariate analysis confirmed that body mass index <18.5 kg/m(2) at this time point is an independent predictor for recurrence (P = .039) and overall survival (P = .043). CONCLUSIONS: Early recurrence can be predicted by malnourished status 3 months after treatment completion. Malnourishment has significant negative effects on overall survival in locally advanced postoperative oral cavity cancer patients who are undergoing adjuvant chemoradiation. After therapy is completed, nutritional guidance and care should be continued for patients with this advanced disease.


Subject(s)
Body Mass Index , Chemoradiotherapy, Adjuvant , Mouth Neoplasms/mortality , Mouth Neoplasms/therapy , Neoplasm Recurrence, Local/epidemiology , Comorbidity , Disease-Free Survival , Female , Follow-Up Studies , Humans , Male , Malnutrition/epidemiology , Middle Aged , Mouth Neoplasms/pathology , Multivariate Analysis , Neoplasm Staging , Nutritional Status , Retrospective Studies , Survival Rate , Treatment Outcome
17.
ISA Trans ; 51(1): 81-94, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21872855

ABSTRACT

In this paper, an efficient decentralized iterative learning tracker is proposed to improve the dynamic performance of the unknown controllable and observable sampled-data interconnected large-scale state-delay system, which consists of N multi-input multi-output (MIMO) subsystems, with the closed-loop decoupling property. The off-line observer/Kalman filter identification (OKID) method is used to obtain the decentralized linear models for subsystems in the interconnected large-scale system. In order to get over the effect of modeling error on the identified linear model of each subsystem, an improved observer with the high-gain property based on the digital redesign approach is developed to replace the observer identified by OKID. Then, the iterative learning control (ILC) scheme is integrated with the high-gain tracker design for the decentralized models. To significantly reduce the iterative learning epochs, a digital-redesign linear quadratic digital tracker with the high-gain property is proposed as the initial control input of ILC. The high-gain property controllers can suppress uncertain errors such as modeling errors, nonlinear perturbations, and external disturbances (Guo et al., 2000) [18]. Thus, the system output can quickly and accurately track the desired reference in one short time interval after all drastically-changing points of the specified reference input with the closed-loop decoupling property.


Subject(s)
Artificial Intelligence , Algorithms , Computer Simulation , Industry/instrumentation , Linear Models , Neural Networks, Computer , Nonlinear Dynamics , Normal Distribution
19.
AJR Am J Roentgenol ; 197(6): 1460-5, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22109303

ABSTRACT

OBJECTIVE: The purpose of this study was to determine whether the use of multiplanar reformatted (MPR) MDCT images in the diagnosis of pulmonary embolism (PE) in children by faculty pediatric radiologists and radiology residents affects reader performance parameters and adds diagnostic value compared with the use of axial MDCT images alone. MATERIALS AND METHODS: This retrospective study was conducted with the images of 60 children (28 boys, 32 girls; mean age, 14.7 ± 3.5 years; range, 3.2-18 years) who consecutively underwent pulmonary CT angiography (CTA) for clinically suspected PE. Two faculty pediatric radiologists and two radiology residents independently reviewed images from each study initially using only axial MDCT images and later using MPR MDCT images in any x-, y-, or z-axis. Diagnostic accuracy, confidence level (1-5 ordinal scale), and interpretation time for MPR MDCT images were compared with those for axial MDCT images by use of the McNemar test and paired Student t test. The kappa coefficient was calculated to assess interobserver agreement. Diagnostic accuracy was compared between faculty pediatric radiologists and radiology residents by logistic regression analysis, and confidence level, interpretation time, and added diagnostic value were evaluated by analysis of variance. RESULTS: Nine of 60 pulmonary CTA studies (15%) were found to show PE. Diagnostic accuracy in detection of PE ranged from 91.7% to 100% (mean, 96.7%) with no significant differences between axial and MPR MDCT images (McNemar test for matched binary pairs, p > 0.50 for each reviewer). Logistic regression showed no significant difference between faculty pediatric radiologists and radiology residents in diagnostic accuracy in detection of PE on axial MDCT images (p = 0.48) or MPR MDCT images (p = 0.24). Confidence level and interobserver agreement were significantly higher and average interpretation time was longer in the evaluation of PE with MPR MDCT images than with axial MDCT images for all reviewers (p < 0.001). Compared with faculty pediatric radiologists, radiology residents had significantly greater increases in confidence level, interobserver agreement, interpretation time, and added diagnostic value using MPR MDCT images than they did using axial MDCT images to diagnose PE (p < 0.001). CONCLUSION: Use of MPR MDCT images for pulmonary CTA in the diagnosis of PE in children significantly increases confidence, interobserver agreement, and interpretation time among faculty pediatric radiologists and radiology residents. Because use of MPR MDCT images results in significantly greater improvements in reading parameters for residents than for faculty members, the routine use of this technique by trainees should be encouraged.


Subject(s)
Angiography/methods , Pulmonary Embolism/diagnostic imaging , Radiographic Image Interpretation, Computer-Assisted/methods , Tomography, X-Ray Computed/methods , Adolescent , Analysis of Variance , Child , Child, Preschool , Contrast Media , Female , Humans , Logistic Models , Male , Retrospective Studies
20.
ISA Trans ; 50(3): 344-56, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21333988

ABSTRACT

In this paper, a digital redesign methodology of the iterative learning-based decentralized adaptive tracker is proposed to improve the dynamic performance of sampled-data linear large-scale control systems consisting of N interconnected multi-input multi-output subsystems, so that the system output will follow any trajectory which may not be presented by the analytic reference model initially. To overcome the interference of each sub-system and simplify the controller design, the proposed model reference decentralized adaptive control scheme constructs a decoupled well-designed reference model first. Then, according to the well-designed model, this paper develops a digital decentralized adaptive tracker based on the optimal analog control and prediction-based digital redesign technique for the sampled-data large-scale coupling system. In order to enhance the tracking performance of the digital tracker at specified sampling instants, we apply the iterative learning control (ILC) to train the control input via continual learning. As a result, the proposed iterative learning-based decentralized adaptive tracker not only has robust closed-loop decoupled property but also possesses good tracking performance at both transient and steady state. Besides, evolutionary programming is applied to search for a good learning gain to speed up the learning process of ILC.


Subject(s)
Algorithms , Artificial Intelligence , Feedback , Models, Theoretical , Signal Processing, Computer-Assisted , Computer Simulation
SELECTION OF CITATIONS
SEARCH DETAIL
...