7,829 research outputs found
A hybrid decision support model to discover informative knowledge in diagnosing acute appendicitis
BACKGROUND: The aim of this study is to develop a simple and reliable hybrid decision support model by combining statistical analysis and decision tree algorithms to ensure high accuracy of early diagnosis in patients with suspected acute appendicitis and to identify useful decision rules. METHODS: We enrolled 326 patients who attended an emergency medical center complaining mainly of acute abdominal pain. Statistical analysis approaches were used as a feature selection process in the design of decision support models, including the Chi-square test, Fisher's exact test, the Mann-Whitney U-test (p < 0.01), and Wald forward logistic regression (entry and removal criteria of 0.01 and 0.05, or 0.05 and 0.10, respectively). The final decision support models were constructed using the C5.0 decision tree algorithm of Clementine 12.0 after pre-processing. RESULTS: Of 55 variables, two subsets were found to be indispensable for early diagnostic knowledge discovery in acute appendicitis. The two subsets were as follows: (1) lymphocytes, urine glucose, total bilirubin, total amylase, chloride, red blood cell, neutrophils, eosinophils, white blood cell, complaints, basophils, glucose, monocytes, activated partial thromboplastin time, urine ketone, and direct bilirubin in the univariate analysis-based model; and (2) neutrophils, complaints, total bilirubin, urine glucose, and lipase in the multivariate analysis-based model. The experimental results showed that the model with univariate analysis (80.2%, 82.4%, 78.3%, 76.8%, 83.5%, and 80.3%) outperformed models using multivariate analysis (71.6%, 69.3%, 73.7%, 69.7%, 73.3%, and 71.5% with entry and removal criteria of 0.01 and 0.05; 73.5%, 66.0%, 80.0%, 74.3%, 72.9%, and 73.0% with entry and removal criteria of 0.05 and 0.10) in terms of accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and area under ROC curve, during a 10-fold cross validation. A statistically significant difference was detected in the pairwise comparison of ROC curves (p < 0.01, 95% CI, 3.13-14.5; p < 0.05, 95% CI, 1.54-13.1). The larger induced decision model was more effective for identifying acute appendicitis in patients with acute abdominal pain, whereas the smaller induced decision tree was less accurate with the test data. CONCLUSIONS: The decision model developed in this study can be applied as an aid in the initial decision making of clinicians to increase vigilance in cases of suspected acute appendicitis
Information technologies for pain management
Millions of people around the world suffer from pain, acute or chronic and this raises the
importance of its screening, assessment and treatment. The importance of pain is attested by
the fact that it is considered the fifth vital sign for indicating basic bodily functions, health
and quality of life, together with the four other vital signs: blood pressure, body
temperature, pulse rate and respiratory rate. However, while these four signals represent an
objective physical parameter, the occurrence of pain expresses an emotional status that
happens inside the mind of each individual and therefore, is highly subjective that makes
difficult its management and evaluation. For this reason, the self-report of pain is considered
the most accurate pain assessment method wherein patients should be asked to periodically
rate their pain severity and related symptoms. Thus, in the last years computerised systems
based on mobile and web technologies are becoming increasingly used to enable patients to
report their pain which lead to the development of electronic pain diaries (ED). This approach
may provide to health care professionals (HCP) and patients the ability to interact with the
system anywhere and at anytime thoroughly changes the coordinates of time and place and
offers invaluable opportunities to the healthcare delivery. However, most of these systems
were designed to interact directly to patients without presence of a healthcare professional
or without evidence of reliability and accuracy. In fact, the observation of the existing
systems revealed lack of integration with mobile devices, limited use of web-based interfaces
and reduced interaction with patients in terms of obtaining and viewing information. In
addition, the reliability and accuracy of computerised systems for pain management are
rarely proved or their effects on HCP and patients outcomes remain understudied.
This thesis is focused on technology for pain management and aims to propose a monitoring
system which includes ubiquitous interfaces specifically oriented to either patients or HCP
using mobile devices and Internet so as to allow decisions based on the knowledge obtained
from the analysis of the collected data. With the interoperability and cloud computing
technologies in mind this system uses web services (WS) to manage data which are stored in a
Personal Health Record (PHR).
A Randomised Controlled Trial (RCT) was implemented so as to determine the effectiveness
of the proposed computerised monitoring system. The six weeks RCT evidenced the
advantages provided by the ubiquitous access to HCP and patients so as to they were able to
interact with the system anywhere and at anytime using WS to send and receive data. In
addition, the collected data were stored in a PHR which offers integrity and security as well
as permanent on line accessibility to both patients and HCP. The study evidenced not only
that the majority of participants recommend the system, but also that they recognize it
suitability for pain management without the requirement of advanced skills or experienced users. Furthermore, the system enabled the definition and management of patient-oriented
treatments with reduced therapist time. The study also revealed that the guidance of HCP at
the beginning of the monitoring is crucial to patients' satisfaction and experience stemming
from the usage of the system as evidenced by the high correlation between the
recommendation of the application, and it suitability to improve pain management and to
provide medical information. There were no significant differences regarding to
improvements in the quality of pain treatment between intervention group and control group.
Based on the data collected during the RCT a clinical decision support system (CDSS) was
developed so as to offer capabilities of tailored alarms, reports, and clinical guidance. This
CDSS, called Patient Oriented Method of Pain Evaluation System (POMPES), is based on the
combination of several statistical models (one-way ANOVA, Kruskal-Wallis and Tukey-Kramer)
with an imputation model based on linear regression. This system resulted in fully accuracy
related to decisions suggested by the system compared with the medical diagnosis, and
therefore, revealed it suitability to manage the pain. At last, based on the aerospace systems
capability to deal with different complex data sources with varied complexities and
accuracies, an innovative model was proposed. This model is characterized by a qualitative
analysis stemming from the data fusion method combined with a quantitative model based on
the comparison of the standard deviation together with the values of mathematical
expectations. This model aimed to compare the effects of technological and pen-and-paper
systems when applied to different dimension of pain, such as: pain intensity, anxiety,
catastrophizing, depression, disability and interference. It was observed that pen-and-paper
and technology produced equivalent effects in anxiety, depression, interference and pain
intensity. On the contrary, technology evidenced favourable effects in terms of
catastrophizing and disability. The proposed method revealed to be suitable, intelligible, easy
to implement and low time and resources consuming. Further work is needed to evaluate the
proposed system to follow up participants for longer periods of time which includes a
complementary RCT encompassing patients with chronic pain symptoms. Finally, additional
studies should be addressed to determine the economic effects not only to patients but also
to the healthcare system
์ถฉ์์ผ ์์ฆ ์ฒญ์๋ ๋ฐ ์ ์ ์ฑ์ธ์์ 2-mSv CT์ ๊ธฐ์กด ์ ๋ CT์ ๋ฏผ๊ฐ๋ ๋ฐ ํน์ด๋: LOCAT์ ์ฌํ ํ์๊ทธ๋ฃน ๋ถ์
ํ์๋
ผ๋ฌธ(๋ฐ์ฌ)--์์ธ๋ํ๊ต ๋ํ์ :์ตํฉ๊ณผํ๊ธฐ์ ๋ํ์ ์ตํฉ๊ณผํ๋ถ,2019. 8. ์ด๊ฒฝํธ.Introduction: To explore heterogeneity across patient or hospital characteristics in the diagnostic sensitivity and specificity of 2-mSv CT relative to conventional-dose CT (CDCT) in adolescents and young adults with suspected appendicitis.
Methods: We used the per-protocol analysis set of a large randomized controlled noninferiority trial conducted between Dec 2013, and Aug 2016, comparing 2-mSv CT and CDCT (typically 7 mSv). The data included 2,773 patients (median age [interquartile range], 28 [21โ35] years) and 160 radiologists from 20 hospitals. We tested for heterogeneity in sensitivity and specificity for the diagnosis of appendicitis across predefined subgroups by patient sex, body size, clinical risk scores for appendicitis, time of CT examination (i.e., working hours [typically 08:00โ17:00 of working days] vs. after hours), CT machines, radiologists experience, previous site experience in 2-mSv CT, and site practice volume. We drew forest plots and tested for additive or multiplicative treatment-by-subgroup interaction on sensitivity and specificity.
Results: The 95% CIs for the between-group differences, particularly for sensitivity, were wide due to small sizes (< 200) for the subgroups of extreme body sizes, high clinical risk score for appendicitis, newer CT machines, hospital with prior experience in 2-mSv CT, and hospitals with small appendectomy volume. Otherwise, the 95% CIs in most subgroups contained the previously reported overall between-group differences as well as null hypothesis value (i.e., 0). There was no significant additive or multiplicative interaction for either sensitivity or specificity.
Conclusions: We found no notable subgroup heterogeneity, which implies that 2-mSv CT can replace CDCT in diverse populations. Further studies are needed for the populations for which our subgroups were small.์๋ก : ๋ณธ ์ฐ๊ตฌ๋ ์ถฉ์์ผ ์์ฆ ์ฒญ์๋
๋ฐ ์ ์ ์ฑ์ธ์์ ๊ธฐ์กด CT์ ๋น๊ตํ์ฌ 2-mSv CT์ ์ง๋จ ๋ฏผ๊ฐ๋ ๋ฐ ํน์ด๋์์ ํ์ ๋๋ ๋ณ์์ ํน์ฑ์ ๋ฐ๋ฅธ ์ด์ง์ฑ์ด ์๋์ง๋ฅผ ํ์ํ๋ ์ฐ๊ตฌ์.
๋ฐฉ๋ฒ: ๋ณธ ์ฐ๊ตฌ๋ 2013๋
12์์์ 2016๋
8์ ์ฌ์ด์ 15โ44์ธ์ ํ์์์ 2-mSv CT์ ๊ธฐ์กด ์ ๋ CT (์ผ๋ฐ์ ์ผ๋ก 7 mSv)๋ฅผ ๋น๊ตํ ๋๊ท๋ชจ ๋น์ด๋ฑ์ฑ ๋ฌด์์๋ฐฐ์ ์์์ํ์ ํ๋กํ ์ฝ ๋ณ ๋ถ์์ธํธ๋ฅผ ์ฌ์ฉํจ. ๋ณธ ์ฐ๊ตฌ์๋ 20๊ฐ ๋ณ์์์ 2,773๋ช
์ ํ์ (์ค์๊ฐ ์ฐ๋ น [์ฌ๋ถ์์ ๋ฒ์], 28 [21โ35]์ธ)๊ฐ ํฌํจ๋์์ผ๋ฉฐ, 160๋ช
์ ํ๋
์๊ฐ ์ฐธ์ฌํจ. ํ์์ ์ฑ๋ณ, ์ ์ฒด ํฌ๊ธฐ, ์ถฉ์์ผ์ ๋ํ ์์ ์ํ ์ ์, CT ๊ฒ์ฌ์๊ฐ (์ผ๊ณผ์๊ฐ [๊ทผ๋ฌด์ผ ๊ธฐ์ค ์ค์ 8์๋ถํฐ ์คํ5์] ๋๋ ์ผ๊ณผ์๊ฐ ์ดํ), CT ์ฅ๋น, ํ๋
์์ ๊ฒฝํ์ ๋, 2-mSv CT์ ๋ํ ์ด์ ๊ฒฝํ ์ฌ๋ถ, ๊ทธ๋ฆฌ๊ณ ๋ณ์์ ์์๊ท๋ชจ ๋ฑ์ ์ฌ์ ์ ์๋ ํ์ ๊ทธ๋ฃน์์ ์ถฉ์์ผ ์ง๋จ์ ์ํ ๋ฏผ๊ฐ๋ ๋ฐ ํน์ด๋์ ์ด์ง์ฑ์ ํ
์คํธํจ. ๋ ๊ตฐ์ ์ฐจ์ด๋ฅผ ์ฒ๊ทธ๋ฆผ์ผ๋ก ์ ์ํ๊ณ , ๋ฏผ๊ฐ๋์ ํน์ด๋์ ๋ํ ๋ง์
๋ฐ ๊ณฑ์
์ํธ์์ฉ์ ํ
์คํธํจ.
๊ฒฐ๊ณผ: ๋ง์ด ๋ ์ฌํ๊ฑฐ๋ ๋ฑ๋ฑํ ๊ฒฝ์ฐ, ์ถฉ์์ผ ์ผ์ฆ ๋ฐ์ ์ ์๊ฐ ๋์ ๊ฒฝ์ฐ, ์ต์ CT ๊ธฐ๊ธฐ๋ฅผ ์ฌ์ฉํ ๊ฒฝ์ฐ, 2-mSV CT ์ ์ด์ ๊ฒฝํ์ด ์๋ ๋ณ์, ๊ทธ๋ฆฌ๊ณ ์ถฉ์์ ์ ์ ๊ท๋ชจ๊ฐ ์์ ๋ณ์์ ๊ฒฝ์ฐ ๋ฑ ํน์ ํ์ ๊ทธ๋ฃน์ ์์ ํฌ๊ธฐ (< 200)๋ก ์ธํด ๋ฏผ๊ฐ๋์ ๋ํ 95 % ์ ๋ขฐ๊ตฌ๊ฐ์ด ๋์์. ๊ทธ ์ธ, ๋๋ถ๋ถ์ ํ์ ๊ทธ๋ฃน์์ ๊ทธ๋ฃน ๊ฐ ์ฐจ์ด์ ๋ํ 95 % ์ ๋ขฐ๊ตฌ๊ฐ์ ์ด์ ๋ณด๊ณ ๋ ์ ์ฒด ๊ทธ๋ฃน ๊ฐ ์ฐจ์ด ๋ฐ ๊ท๋ฌด ๊ฐ์ค ๊ฐ (์ฆ, 0)์ ํฌํจํ์์. 2-mSv CT ๊ตฐ๊ณผ ๊ธฐ์กด ์ ๋ CT ๊ตฐ ๊ฐ์ ๋ฏผ๊ฐ๋ ๋ฐ ํน์ด๋์์ ๋ง์
๋๋ ๊ณฑ์
์ํธ์์ฉ์ ๋ณด์ด๋ ํ์ ๊ทธ๋ฃน์ ์์์.
๊ฒฐ๋ก : ์ถฉ์์ผ ์์ฆ ์ฒญ์๋
๊ณผ ์ ์ ์ฑ์ธ์์ 2-mSv CT์ ๊ธฐ์กด ์ ๋ CT ๊ฐ์ ๋ฏผ๊ฐ๋์ ํน์ด๋์์ ์ด์ง์ฑ์ ๋ณด์ด๋ ํ์๊ทธ๋ฃน์ ์์์. ์ด๋ 2-mSv CT๊ฐ ๋ค์ํ ์ง๋จ์์ ๊ธฐ์กด ์ ๋ CT๋ฅผ ๋์ฒดํ ์ ์์์ ์๋ฏธํจ. ๋ค๋ง, ๋ณธ ์ฐ๊ตฌ์์ ์์ ํฌ๊ธฐ๋ฅผ ๊ฐ์ง ์ผ๋ถ ํ์ ๊ทธ๋ฃน์ ๋ํด์๋ ์ถ๊ฐ์ ์ธ ์ฐ๊ตฌ๊ฐ ํ์ํจ.INTRODUCTION 1
Motivations of LOCAT 1
Purposes of LOCAT 3
Motivations of Dissertation Research 4
Purposes of Dissertation Research 5
BACKGROUND 7
Epidemiology of Appendicitis and CT utilization 7
Imaging Utilization 7
Popularity of CT 8
CT Radiation 9
Radiation Dose Level 10
Typical Radiation Dose for Multi-purpose Abdomen CT 10
Typical Radiation Dose for Appendiceal CT 11
Low Doses Explored in Research Settings 12
Carcinogenic Risk Associated with CT Radiation 12
Controversy 13
ALARA Principle 14
Efficacy and Effectiveness of LDCT Compared to CDCT 15
Clinical Outcome 19
Diagnostic Performance 20
Inter-observer Agreement 21
Differentiation between Complicated vs. Uncomplicated Appendicitis 22
Image Quality 24
Visualization of the Appendix 24
Alternative Diagnoses 25
Step-wise Multimodal Diagnostic Approach Incorporating LDCT 27
Patient Subgroups Less Benefited from LDCT 27
Selective Utilization of LDCT 29
Additional Imaging Test(s) Following LDCT 30
Imaging Techniques for LDCT for Suspected Appendicitis 31
Intravenous Contrast Enhancement 31
Contrast-enhancement Phase 31
Enteric Contrast 32
Anatomical Coverage 32
Tube Current 33
Tube Potential 34
Iterative Reconstruction 34
Image Reconstruction Thickness 35
Coronal Reformation 35
Sliding-Slab Averaging Technique 36
Image Interpretation and Reporting for LDCT 37
Diagnostic Criteria for Appendicitis 37
Structured Reporting 38
Other Practical Issues in Implementing LDCT 39
Dedicated Protocol for Appendiceal CT 40
Education for Referring Physicians and Surgeons 41
Education for Radiologists 42
Dose Calibration and Monitoring 43
MATERIALS AND METHODS 47
Study Overview 47
Practice Setting 48
Pre-registration Procedures 48
Study Organization and Site Recruitment 49
Site Activation 50
Patients 51
Eligibility Criteria 54
Clinical Suspicion for Appendicitis 55
The Need for CT Examination 55
Generalizability 56
Representativeness of Study Sample 57
Withdrawal Criteria 58
Randomization 58
Index Test 59
CT Image Acquisition and Archiving 66
Radiation Doses 69
Record of Modulated Radiation Dose 71
Target Median DLP Values for the 2-mSv CT and CDCT groups 71
Calibration of Radiation Doses 72
Estimation of Carcinogenic Risk Associated with CT Examination 74
Image Interpretation 75
Radiologists and CT Reports 76
Radiologist Training 78
Considerations Regarding Technical Advantages over Previous Studies 79
Image Submission 80
Co-intervention 81
Additional Imaging 82
General Treatment Guidelines 82
Follow-up 84
Endpoints in LOCAT 85
Primary Endpoint 86
Secondary Endpoints 86
Considerations for NAR and APR 89
Changes in Endpoints 89
Reference Standards 91
Overview of Reference Standards 91
Definition of Acute Appendicitis 92
Mild or Early Acute Appendicitis 92
Appendiceal Diverticulitis 93
Cases of Delayed Appendectomy 93
Periappendicitis 93
Definition of Appendiceal Perforation 94
Reporting AEs 95
Definition of AE 96
Definition of SAE 97
AE Characteristics 97
Grade 98
Expected/Unexpected AEs 98
Attribution 98
Individual Symptoms vs. Single Diagnosis 99
Who Should Report AEs 99
How to Report AEs 99
Follow-up for AEs 100
Ethical Considerations 100
Ethics and Responsibility 100
Informed Consent Form 101
Data Security and Participant Confidentiality 101
Early Stopping Rules in LOCAT 101
Data Management 102
Case Report Forms 103
Monitoring Participant Accrual 103
Monitoring Data Quality 103
Data and Safety Monitoring Board 105
Statistical Analysis 105
Considerations for Primary Endpoint 105
Analysis Plans 107
Sample Size 108
Sample Size Considerations 108
Final Sample Size 110
Rationale for the Noninferiority Margin 111
Reported NARs Following Preoperative CT 111
Reported NARs in Patients Without Preoperative CT 112
Sample Size Considerations on APR 113
Subgroup Analyses for APR and NAR 114
Subgroup Analyses for Diagnostic Performance 116
RESULTS 119
Patient Characteristics 119
Overall Diagnostic Performance 123
Subgroups of Limited Comparison 123
Between-group Differences for Subgroups 123
Heterogeneity 131
DISCUSSION 132
CONCLUSION 139
REFERENCES 140
APPENDIX 164
Abstract in Korean 176Docto
Advances in the diagnosis of acute aortic syndromes: Role of imaging techniques.
Aortic diseases include a wide range of pathological conditions: aortic aneurysms, pseudoaneurysms, acute aortic syndromes, atherosclerotic and inflammatory conditions, genetic diseases and congenital anomalies. Acute aortic syndromes have acute onset and may be life-threatening. They include aortic dissection, intramural haematoma, penetrating aortic ulcer and traumatic aortic injury. Pain is the common denominator to all acute aortic syndromes. Pain occurs regardless of age, gender and other associated clinical conditions. In this review, we deal with the main findings in the clinical setting and the most recent indications for diagnostic imaging, which are aimed to start an appropriate treatment and improve the short- and long-term prognosis of these patients.
ยฉ The Author(s) 2016
Evolution and challenges in the design of computational systems for triage assistance
AbstractCompared with expert systems for specific disease diagnosis, knowledge-based systems to assist decision making in triage usually try to cover a much wider domain but can use a smaller set of variables due to time restrictions, many of them subjective so that accurate models are difficult to build. In this paper, we first study criteria that most affect the performance of systems for triage assistance. Such criteria include whether principled approaches from machine learning can be used to increase accuracy and robustness and to represent uncertainty, whether data and model integration can be performed or whether temporal evolution can be modeled to implement retriage or represent medication responses. Following the most important criteria, we explore current systems and identify some missing features that, if added, may yield to more accurate triage systems
CT dose optimization with model based iterative reconstruction
The aim of this thesis is to assess the feasibility of using model-based iterative reconstruction (MBIR) to develop new low-dose CT (computed tomography) protocols in the areas of neck, chest, and abdominal imaging without compromising diagnostic performance. Medical imaging has become the largest source of radiation exposure for humans other than natural background radiation. The availability of and improvements in diagnostic imaging have led to a sevenfold increase in the use of imaging over the past 30 years. This is especially true for CT, with a 7.8% annual increase in the use of CT from 1996 to 2010. The major concern associated with the widespread uptake of CT is the parallel increase in radiation exposure incurred by patients, and while the relationship of diagnostic radiation exposure to a quantifiable risk of cancer induction remains a controversial topic, physicians are beholden to keep radiation doses from diagnostic imaging as low as reasonably possible to limit the risk of radiation-induced cancer. We conducted preliminary phantom and cadaveric studies to examine the performance of MBIR at different radiation dose levels in the thorax and abdomen. Cadavers and phantoms provide a means of safely assessing new technologies and optimizing scan protocols prior to clinical validation. An anthropomorphic torso phantom and 5 human cadavers were scanned at varying radiation dose levels and images reconstructed using three different reconstruction techniques: filtered back projection, hybrid IR and MBIR. MBIR reduced image noise and improved image quality even in CT images acquired with a mean radiation dose reduction of 62%, compared with conventional dose studies reconstructed with hybrid IR, with lower levels of objective image noise, superior diagnostic acceptability and contrast resolution, and comparable subjective image noise and streak artifact scores. We subsequently performed clinical studies with the objectives of assessing MBIR as a tool for image quality improvement and radiation dose reduction in CT, and for the development of new low-dose carotid angiography, chest, and abdominopelvic CT protocols. We developed a low-dose carotid CTA protocol reconstructed with MBIR comparable to a conventional dose CTA protocol in terms of image quality and diagnostic accuracy while enabling a dose reduction of 49.6%. 20 patients were scanned using a split-dose technique with radiation dose divided into a low-dose acquisition reconstructed with MBIR and a conventional dose acquisition reconstructed with hybrid IR. Mean effective dose was significantly lower for the low-dose studies (1.84mSv versus 3.71mSv) and subjective image noise, contrast resolution, and spatial resolution were significantly higher for the low-dose studies. There was excellent agreement for stenosis grading accuracy between low- and conventional dose studies (Cohen ฮบ = 0.806). A modified low-dose CT thorax protocol reconstructed with MBIR was also developed to monitor pulmonary disease progression in patients with cystic fibrosis with our low-dose protocol enabling the acquisition of a full-volume diagnostic quality chest CT at a dose equivalent to that of a chest radiograph (0.09ยฑ0.01mSv). Finally, we assessed the feasibility of low-dose abdominopelvic CT performed with MBIR as a radiation dose reduction strategy for imaging patients presenting with acute abdominal pain. A 74.7% mean radiation dose reduction was achieved with scans performed in the peri- and submillisievert range in patients of normal and low BMI, respectively, without compromising diagnostic performance. Dose reduction to the submillisievert range for patients with an elevated BMI was a challenge. The current era is extremely exciting in terms of radiation dose optimization in CT. This thesis is a demonstration of the potential for substantial reductions in radiation exposure, when the benefits of iterative reconstruction are combined with automated tube current modulation and other CT scanner technologies. The combination of all these hardware and software developments is now seeing major benefits for the patient and moving beyond the narrow aim of radiation exposure reduction to a complete change in practice, towards replacement of conventional radiography with low-dose CT, without any penalty for the patient in terms of radiation exposure
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