Diagnostic imaging evaluating image quality using visual grading characteristic (VGC) analysis

Size: px
Start display at page:

Download "Diagnostic imaging evaluating image quality using visual grading characteristic (VGC) analysis"

Transcription

1 Vet Res Commun (2010) 34: DOI /s SHORT COMMUNICATION Diagnostic imaging evaluating image quality using visual grading characteristic (VGC) analysis Eberhard Ludewig & Andreas Richter & Mairi Frame Accepted: 26 April 2010 / Published online: 12 May 2010 # Springer Science+Business Media B.V Abstract Radiologists are regularly faced with the task of comparing image quality obtained using different imaging systems or settings. Visual grading techniques can be used to evaluate the quality of images by grading the clarity of reproduction of anatomical or pathological structures. The methods, which include visual grading analysis (VGA) and the image criteria (IC) study, are characterised by their attractive simplicity and reliability. Non-parametric rank-invariant statistical methods are suitable techniques for statistical analysis of VGA-data. Båth and Månsson (2007) introduced such a method and termed it visual grading characteristics (VGC) analysis. This paper gives an overview of the principle together with an example of its use in veterinary radiology. The aim of this review article is to encourage veterinary researchers to apply this method which has proven valuable in the human field. Basically, the method can also be applied for the analysis of other categories of images (e.g. histological sections, cytological smears) in cases where the task is to evaluate features subjectively on the basis of a score, allowing some degree of freedom of decision. Furthermore, the aim of the investigation is not necessarily restricted to quality aspects. Other questions such as the effects of treatment options on the appearance of certain structures can be compared as well. Keywords Statistics. Data analysis. Visual grading characteristics analysis. Radiology E. Ludewig (*) Department of Small Animal Medicine, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 23, Leipzig, Germany ludewig@vetmed.uni-leipzig.de A. Richter Large Animal Clinic for Theriogenology and Ambulatory Services, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 29, Leipzig, Germany M. Frame Royal (Dick) School of Veterinary Studies, Division of Veterinary Clinical Sciences, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Roslin, Midlothian, GB-Scotland EH25 9RG, UK

2 474 Vet Res Commun (2010) 34: Introduction A number of established techniques exist to assess the quality of images, including physical methods, 1 psychophysical methods, 2 and techniques whereby an observer assesses the visibility of certain features within clinical images. Of these observer performance methods, which include preference studies, receiver operating characteristic (ROC) analysis, image criteria (IC) study, and visual grading analysis (VGA), the last two have been demonstrated to be useful for several reasons: (1) The observer s rating takes account of the contribution of all technical components of the imaging chain in reproducing image structures (i.e. image recording, postprocessing, display quality on film or a monitor) and the experience of the reader. This is one reason why the practical validity is assumed to be high. (2) The assessment of image quality is based on the visualisation of clinically relevant structures which can be selected and defined using established standards if available. (3) The studies are relatively easy to perform, in comparison with ROC studies. In ROC studies simulated lesions are used to mimic pathology. It takes some effort to create phantoms which reflect clinical conditions adequately. (4) The studies require only moderate time input by participating observers; hence the barriers to undertaking them should be low. (5) Visual grading characteristic (VGC) analysis is a valid new method of analysing data obtained from either VGA or IC-studies. The purpose of this review is to demonstrate the basic methodology of VGC analysis with a view to encouraging veterinary radiologists to utilize this technique. Visual grading analysis (VGA) There are two ways to perform VGA: & as relative grading & as absolute grading In relative VGA-studies one or several reference images are needed. The observer compares the display quality of the target structure of the test image with the corresponding landmark of the reference image. A scale with 3, 5, or 7 points is used to categorize the observer decision (e.g. a 5-step scale comparing visibility would appear thus: +2 = much better, +1 = slightly better, 0 = equal, 1 = slightly worse, 2 much worse). In absolute VGA-studies the observer states his opinion on the visibility of a certain feature without a reference image, using an absolute scale, typically consisting of 4 to 7 points (Table 1). VGA-studies can be used to evaluate anatomical or pathological structures and physical quality parameters. The majority of human studies focus on the evaluation of anatomical structures. The underlying theory is that the ability to detect pathology correlates well with accurate anatomical presentation. In contrast with pathological structures, anatomical landmarks have a more uniform appearance and therefore are more easily to describe. In 1 e.g. by calculating the detective quantum efficiency (DQE), the modulation transfer function (MTF), or the signal-to-noise ratio 2 e.g. contrast-detail diagrams

3 Vet Res Commun (2010) 34: Table 1 Examples for rating scales (A) Image Criteria (IC) - Study 1 - clear confident that the criterion is fulfilled 2 - somewhat confident that the criterion is fulfilled 3 - indecisive whether the criterion is fulfilled or not 4 - somewhat confident that the criterion is not fulfilled 5 - clear confident that the criterion is not fulfilled (B) relative Visual Grading Analysis (VGA) - Study 1 - test image clear superior to reference image 2 - test image somewhat superior to reference image 3 - test image equal to reference image 4 - test image somewhat inferior to reference image 5 - test image clear inferior to reference image (C) absolute Visual Grading Analysis (VGA) - Study 1 - excellent image quality: no limitations for clinical use 2 - good image quality: minimal limitations for clinical use 3 - sufficient image quality: moderate limitations for clinical use but no substantial loss of information 4 - restricted image quality: relevant limitations for clinical use, clear loss of information 5 - poor image quality: image not usable, loss of information, image must be repeated human studies the assessment of anatomical structures is often based on quality standards which have been established for a variety of examinations (CEC Report Eur ; CEC Report Eur ; CEC Report Eur ). Since the criteria for the presentation of target structures investigated in human studies follow identical standards, results obtained from different studies are comparable to a certain degree. Despite the lack of such quality standards in veterinary radiology, generally accepted principles of display characteristics could be used as basics for VGA-studies. The results of a VGA study can be summarised in a VGA-score (VGAS): P S C O;I VGAS ¼ N i N o S C for observer (O) and images (I) Ni total number of images No total number of observers With commercially available software, differences in the ratings can be tested using the analysis of variance (ANOVA) in combination with a test for multiple comparisons in order to reduce the risk of random significance. This method of data analysis has met with criticism since the statistical analysis of VGA-score is based upon the assumption that the scale steps characterize a discrete quantitative variable (Båth and Månsson 2007; Geijer et al. 2001). However they belong to an ordered qualitative variable and therefore it is inappropriate to transform it into numerical values. For this reason the mathematical and statistical validity of VGA-score is questionable. Strengths and weaknesses of the VGA methodology are discussed in detail in the literature (Månsson 2000; Båth and Månsson 2007).

4 476 Vet Res Commun (2010) 34: Image criteria (IC) study In an IC-study the observer is asked to state his opinion about the fulfilment of a certain quality criteria (in a yes-or-no decision). An IC-score is calculated as the ratio of the number of fulfilled criteria to the overall number of criteria assessed (Båth and Månsson 2007). In a modified version the extent of fulfilment of the criteria is also stated. In this extended version a multi-step categorization is available for further analysis (Table 1). As with VGA, the criteria for image quality assessment can be based on established standards of the required level of reproduction of important image structures (Månsson 2000; Båth and Månsson 2007). Visual grading characteristic (VGC) analysis Procedure As mentioned above the analysis of rating data from ordinal scales (e.g. from IC- or VGAstudies) requires non-parametric rank-invariant statistical methods (Sonn and Svensson 1997). Bath and Mansson (2007) introduced a method, which fulfils this requirement. The method, termed visual grading characteristics (VGC) analysis, treats the scale steps as ordinal with no assumptions of the distribution of the data being made. It handles visual grading data in similar fashion to ROC-data (Metz 1986). VGC-analysis can be applied to data from an expanded IC-study or a VGA-study (relative or absolute). VGC-analysis on the basis of IC-data can be considered as a repeated scoring, where the observer is able to adapt the degree of confidence of his decision concerning the fulfilment of pre-defined criteria. A VGC-analysis with data from a VGAstudy follows quite similar principles: the observer uses multiple scale steps to state his opinion about the image quality. Despite the differences in the meaning (IC-studies characterize the observers confidence about the fulfilment of a specific image quality criterion; VGA characterize the observers opinion about the reproduction of a certain structure) the statistical fundamentals of resulting data are the same. There are methodical similarities to ROC-studies. In ROCstudies the observer uses scale steps to state his confidence of each positive ( signal, disease ) or negative ( noise, normality ) decision (Metz 1986; van Erkel and Pattynama 1998). VGC-analysis is performed stepwise. In a first step a frequency table (2 n frequency table, n = number of categories) summarizes the results for the two modalities (A, B) separately. In a second step the VGC data points are calculated in a table. These points represent the coordinates of the VGC-curve. As in a ROC curve the origin of a VGC-curve per definition is 0. The following data points are arranged according to the cumulative (relative) frequencies of the corresponding categories. The last point includes all decisions and therefore is 1. The theoretical background will be clarified by an example below. Suitable ROC software 3,4,5 can be used for plotting the VGC-curve and for calculating the Area under the curve (AUC VGC ). The AUC VGC can be taken as a measure of the 3 ROCKFIT, Kurt Rossmann Laboratories for Radiologic Image Research, University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA 4 SigmaStat, Systat Software Inc., 1735, Technology Drive, Ste 430, San Jose, CA 95110, USA 5 SPSS 14.0, SPSS Inc. Headquarters, 233 S. Wacker Drive, 11th floor, Chicago, IL 60606, USA

5 Vet Res Commun (2010) 34: difference in the image quality between two modalities or settings. Standard statistical procedures are used for calculating confidence intervals and p-values and for statistical testing. A curve equal or close to the diagonal, equivalent to an AUC VGC of around 0.5, indicates equality between the modalities or conditions investigated. Practical application To illustrate the practical application of the techniques described above, we use the example of a fictitious study comparing the display properties of two modalities (e.g. different digital detectors) in order to identify the superior system. The method can also be adopted for other purposes, e.g. to investigate the influence of exposure levels or of differences in postprocessing in a given digital system etc. In latero-lateral canine thoracic radiographs obtained by each system, the reproducibility of a number of target structures, for example the trachea, is assessed. The practical application of this feature mainly depends on the degree of visualisation of the boundaries of the trachea and the stem bronchi, so by definition a visually sharp delineation of these structures from the adjacent mediastinum and lung is required. Depending on the type of study, the categories of 5-step rating scales are specifically defined. In order to facilitate interpretation and to improve interobserver agreement it is important to translate the numerical scale-step into well-defined verbal description of the signification of each category (Table 1). For further illustration, data from a fictitious absolute VGA-study are used. A blinded observer evaluated the target structure in 100 radiographs from each of the two detector systems (A and B) using the categories from Table 1c. The results are summarized in Table 2. The visual grading characteristics (VGC) data points (pairs of VGA scores) obtained from the data presented in Table 2 are shown in Table 3. The calculated AUC VGC is 0.69 with a standard error of The 95% confidence interval (0.62, 0.77) is above 0.5 (Fig. 1). So it can be stated, the modality B offers a statistically superior image quality in comparison to modality A (with regard to the specific criterion and observer). Pros and cons The strengths of the VGC-analysis can be summarized as follows: (1) IC- or VGA-studies provide the data for VGC-analysis. Therefore the method offers high validity since it is based on assessment of clinically relevant structures. Although Table 2 Results of a fictitious absolute VGA-study Grade Number of Decisions Modality A Modality B Total

6 478 Vet Res Commun (2010) 34: Table 3 Data points of the VGC-study (calculated from results of Table 2) VGA A VGA B (Modality A) (Modality B) established quality standards as used in human radiology are not yet available in the veterinary field, it should be relatively straightforward to define relevant quality criteria for veterinary examinations. (2) The evaluation includes a measure of the observer s self reported confidence on a decision, which is analogous to the daily clinical situation. (3) In comparison to ROC-studies the expenditure of work to perform IC- or VGA-studies is significantly less. Preparation of the reading session in particular is comparably less laborious. This is a further argument to encourage veterinary radiologist to adopt the methodology. (4) The statistical methodology of VGC-analysis is appropriate when using a nonparametric rank-invariant approach to analyse data from an ordinal scale. (5) Major aspects of criticism relate to the same arguments given for the analysis of uncertain ROC-data (Båth and Månsson 2007; van Erkel and Pattynama 1998). So difficulties exist in the interpretation of curves crossing the diagonal. Further, if in ICstudies a large proportion of the decision has a low threshold and therefore represents 1 VGA B AUC VGC = 0.69 standard error: ± % confidence interval: p-value: < VGA A Fig. 1 VGC-curve obtained from the data presented in Tables 2 and 3. The boxes are the coordinates corresponding to the observer s interpretation of the scale steps of the rating scale. The Area under the curve (AUG VGC ) is statistically different from 0.5. Modality B offers a statistically significant superior image quality

7 Vet Res Commun (2010) 34: uncertain decision question arise about their meaning, because the underlying reasons such as poor image quality, observer influence etc. cannot be identified. In detail these aspects are discussed in the literature (Båth and Månsson 2007). In conclusion, VGC-analysis is a valid option for the quantitative assessment of image quality in veterinary radiology. The method also can be applied to other types of images (e.g. histological sections, cytological smears) or other objects of inquiry. References Båth, M., Månsson, L.G., Visual grading characteristics (VGC) analysis: a non-parametric rankinvariant statistical method for image quality analysis. The British Journal of Radiology 80, CEC (Commission of the European Community), European guidelines on quality criteria for diagnostic radiographic images. Report EUR EN. Luxembourg: Office for official publications of the European Communities. CEC (Commission of the European Community), European guidelines on quality criteria for diagnostic radiographic images in paediatrics. Report EUR EN. Luxembourg: Office for official publications of the European Communities. EuropeanGuidelinesEur16261.pdf. CEC (Commission of the European Community), European guidelines on quality criteria for computed tomography. Report EUR EN. Luxembourg: Office for official publications of the European Communities. Criteria_Computed_Tomography_Eur_16252.pdf. Published May Geijer, H., Verdonck, B., Beckman, K.W., Andersson, T., Persliden, J., Digital radiography of scoliosis with a scanning method: initial evaluation. Radiology 218, Månsson, L.G., Methods for the evaluation of image quality: A review. Radiation Protection Dosimetry 90, Metz, C.E., ROC methodology in radiologic imaging. Investigative Radiology 21, Sonn, U., Svensson, E., Measures of individual and group changes in ordered categorical data: application to the ADL staircase. Scandinavian Journal of Rehabilitation Medicine 29, van Erkel, A.R., Pattynama, P.M., Receiver operating characteristic (ROC) analysis: basic principles and applications in radiology. European Journal of Radiology 27, 88 94

CT Optimisation for Paediatric SPECT/CT Examinations. Sarah Bell

CT Optimisation for Paediatric SPECT/CT Examinations. Sarah Bell CT Optimisation for Paediatric SPECT/CT Examinations Sarah Bell Sarah.bell14@nhs.net Outline 1. Introduction 2. Aims and Objectives 3. Methods 4. Results 5. Discussion 6. Conclusions 7. References Introduction

More information

METHODS FOR DETECTING CERVICAL CANCER

METHODS FOR DETECTING CERVICAL CANCER Chapter III METHODS FOR DETECTING CERVICAL CANCER 3.1 INTRODUCTION The successful detection of cervical cancer in a variety of tissues has been reported by many researchers and baseline figures for the

More information

Mammography limitations. Clinical performance of digital breast tomosynthesis compared to digital mammography: blinded multi-reader study

Mammography limitations. Clinical performance of digital breast tomosynthesis compared to digital mammography: blinded multi-reader study Clinical performance of digital breast tomosynthesis compared to digital mammography: blinded multi-reader study G. Gennaro (1), A. Toledano (2), E. Baldan (1), E. Bezzon (1), C. di Maggio (1), M. La Grassa

More information

FDA Executive Summary

FDA Executive Summary Meeting of the Radiological Devices Advisory Panel On October 24, 22, the panel will discuss, make recommendations, and vote on a premarket approval application supplement (P83/S) to expand the indications

More information

UNIVERSITY OF THE FREE STATE DEPARTMENT OF COMPUTER SCIENCE AND INFORMATICS CSIS6813 MODULE TEST 2

UNIVERSITY OF THE FREE STATE DEPARTMENT OF COMPUTER SCIENCE AND INFORMATICS CSIS6813 MODULE TEST 2 UNIVERSITY OF THE FREE STATE DEPARTMENT OF COMPUTER SCIENCE AND INFORMATICS CSIS6813 MODULE TEST 2 DATE: 3 May 2017 MARKS: 75 ASSESSOR: Prof PJ Blignaut MODERATOR: Prof C de Villiers (UP) TIME: 2 hours

More information

Lecturer: Rob van der Willigen 11/9/08

Lecturer: Rob van der Willigen 11/9/08 Auditory Perception - Detection versus Discrimination - Localization versus Discrimination - - Electrophysiological Measurements Psychophysical Measurements Three Approaches to Researching Audition physiology

More information

Lecturer: Rob van der Willigen 11/9/08

Lecturer: Rob van der Willigen 11/9/08 Auditory Perception - Detection versus Discrimination - Localization versus Discrimination - Electrophysiological Measurements - Psychophysical Measurements 1 Three Approaches to Researching Audition physiology

More information

Introduction to ROC analysis

Introduction to ROC analysis Introduction to ROC analysis Andriy I. Bandos Department of Biostatistics University of Pittsburgh Acknowledgements Many thanks to Sam Wieand, Nancy Obuchowski, Brenda Kurland, and Todd Alonzo for previous

More information

Higher National Unit Specification. General information for centres. Visceral and Dynamic Imaging. Unit code: DW93 34

Higher National Unit Specification. General information for centres. Visceral and Dynamic Imaging. Unit code: DW93 34 Higher National Unit Specification General information for centres Unit title: Visceral and Dynamic Imaging Unit code: DW93 34 Unit purpose: This Unit enables the candidate to continue to acquire knowledge

More information

Teaching A Way of Implementing Statistical Methods for Ordinal Data to Researchers

Teaching A Way of Implementing Statistical Methods for Ordinal Data to Researchers Journal of Mathematics and System Science (01) 8-1 D DAVID PUBLISHING Teaching A Way of Implementing Statistical Methods for Ordinal Data to Researchers Elisabeth Svensson Department of Statistics, Örebro

More information

Sample Size Considerations. Todd Alonzo, PhD

Sample Size Considerations. Todd Alonzo, PhD Sample Size Considerations Todd Alonzo, PhD 1 Thanks to Nancy Obuchowski for the original version of this presentation. 2 Why do Sample Size Calculations? 1. To minimize the risk of making the wrong conclusion

More information

Critical reading of diagnostic imaging studies. Lecture Goals. Constantine Gatsonis, PhD. Brown University

Critical reading of diagnostic imaging studies. Lecture Goals. Constantine Gatsonis, PhD. Brown University Critical reading of diagnostic imaging studies Constantine Gatsonis Center for Statistical Sciences Brown University Annual Meeting Lecture Goals 1. Review diagnostic imaging evaluation goals and endpoints.

More information

Measures. David Black, Ph.D. Pediatric and Developmental. Introduction to the Principles and Practice of Clinical Research

Measures. David Black, Ph.D. Pediatric and Developmental. Introduction to the Principles and Practice of Clinical Research Introduction to the Principles and Practice of Clinical Research Measures David Black, Ph.D. Pediatric and Developmental Neuroscience, NIMH With thanks to Audrey Thurm Daniel Pine With thanks to Audrey

More information

Doses from pediatric CT examinations in Norway Are pediatric scan protocols developed and in daily use?

Doses from pediatric CT examinations in Norway Are pediatric scan protocols developed and in daily use? Doses from pediatric CT examinations in Norway Are pediatric scan protocols developed and in daily use? Eva Godske Friberg * Norwegian Radiation Protection Authority, P.O. Box, Østerås, Norway Abstract.

More information

Cover Page. The handle holds various files of this Leiden University dissertation

Cover Page. The handle   holds various files of this Leiden University dissertation Cover Page The handle http://hdl.handle.net/1887/40114 holds various files of this Leiden University dissertation Author: Exter, Paul L. den Title: Diagnosis, management and prognosis of symptomatic and

More information

Audit Report. National Audit of Paediatric Radiology Services in Hospitals

Audit Report. National Audit of Paediatric Radiology Services in Hospitals Audit Report National Audit of Paediatric Radiology Services in Hospitals www.rcr.ac.uk 2 Contents Introduction 3 Standards 4 Material and methods 5 Results 6 Discussion 8 References 10 www.rcr.ac.uk 3

More information

Policy Library Clinical Advantages of Digital Breast Tomosynthesis in Symptomatic Patients

Policy Library Clinical Advantages of Digital Breast Tomosynthesis in Symptomatic Patients Policy Library Clinical Advantages of Digital Breast Tomosynthesis in Symptomatic Patients Version: 1 Approved by: Faculty of Clinical Radiology Council Date of approval: Click and type: day month and

More information

Quantitative Methods in Computing Education Research (A brief overview tips and techniques)

Quantitative Methods in Computing Education Research (A brief overview tips and techniques) Quantitative Methods in Computing Education Research (A brief overview tips and techniques) Dr Judy Sheard Senior Lecturer Co-Director, Computing Education Research Group Monash University judy.sheard@monash.edu

More information

Radiation Protection Dosimetry Advance Access published April 22, 2008

Radiation Protection Dosimetry Advance Access published April 22, 2008 Radiation Protection Dosimetry Advance Access published April 22, 2008 Radiation Protection Dosimetry (2008), pp. 1 5 doi:10.1093/rpd/ncn144 EVALUATION OF EXPOSURE PARAMETERS IN PLAIN RADIOGRAPHY: A COMPARATIVE

More information

The value of the craniocaudal mammographic view in breast cancer detection: A preliminary study

The value of the craniocaudal mammographic view in breast cancer detection: A preliminary study The value of the craniocaudal mammographic view in breast cancer detection: A preliminary study P D Trieu 1, Prof. P C Brennan 1, Dr. W Lee 2, Dr. E Ryan 1, Dr. W Reed 1, Dr. M Pietrzyk 1 1. Medical Image

More information

"Optimal Dose Techniques and Image Quality: Can We Have Both?" Lorusso, J. R., Fitzgeorge, L., Lorusso, D., & Lorusso, E. 2014

Optimal Dose Techniques and Image Quality: Can We Have Both? Lorusso, J. R., Fitzgeorge, L., Lorusso, D., & Lorusso, E. 2014 "Optimal Dose Techniques and Image Quality: Can We Have Both?" Lorusso, J. R., Fitzgeorge, L., Lorusso, D., & Lorusso, E. 2014 Introduction Background Important to regularly investigate dose optimization

More information

Pediatric Lung Ultrasound (PLUS) In Diagnosis of Community Acquired Pneumonia (CAP)

Pediatric Lung Ultrasound (PLUS) In Diagnosis of Community Acquired Pneumonia (CAP) Pediatric Lung Ultrasound (PLUS) In Diagnosis of Community Acquired Pneumonia (CAP) Dr Neetu Talwar Senior Consultant, Pediatric Pulmonology Fortis Memorial Research Institute, Gurugram Study To compare

More information

WDHS Curriculum Map Probability and Statistics. What is Statistics and how does it relate to you?

WDHS Curriculum Map Probability and Statistics. What is Statistics and how does it relate to you? WDHS Curriculum Map Probability and Statistics Time Interval/ Unit 1: Introduction to Statistics 1.1-1.3 2 weeks S-IC-1: Understand statistics as a process for making inferences about population parameters

More information

To Shield or Not to Shield? Lincoln L. Berland, M.D.

To Shield or Not to Shield? Lincoln L. Berland, M.D. To Shield or Not to Shield? Lincoln L. Berland, M.D. Disclosures Consultant to: Nuance, Inc. Page 2 Breast Radiation on CT Use of chest CT has increased in women vulnerable to cancer induction by radiation.

More information

Improved image quality of low-dose thoracic CT examinations with a new postprocessing software*

Improved image quality of low-dose thoracic CT examinations with a new postprocessing software* JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS, VOLUME 11, NUMBER 3, Summer 2010 Improved image quality of low-dose thoracic CT examinations with a new postprocessing software* Anne Catrine Traegde Martinsen,

More information

Describe what is meant by a placebo Contrast the double-blind procedure with the single-blind procedure Review the structure for organizing a memo

Describe what is meant by a placebo Contrast the double-blind procedure with the single-blind procedure Review the structure for organizing a memo Business Statistics The following was provided by Dr. Suzanne Delaney, and is a comprehensive review of Business Statistics. The workshop instructor will provide relevant examples during the Skills Assessment

More information

Since its introduction in 2000, digital mammography has become

Since its introduction in 2000, digital mammography has become Review Article Smith A, PhD email : Andrew.smith@hologic.com Since its introduction in 2000, digital mammography has become an accepted standard of care in breast cancer screening and has paved the way

More information

COMPARING SEVERAL DIAGNOSTIC PROCEDURES USING THE INTRINSIC MEASURES OF ROC CURVE

COMPARING SEVERAL DIAGNOSTIC PROCEDURES USING THE INTRINSIC MEASURES OF ROC CURVE DOI: 105281/zenodo47521 Impact Factor (PIF): 2672 COMPARING SEVERAL DIAGNOSTIC PROCEDURES USING THE INTRINSIC MEASURES OF ROC CURVE Vishnu Vardhan R* and Balaswamy S * Department of Statistics, Pondicherry

More information

Prepared by: Assoc. Prof. Dr Bahaman Abu Samah Department of Professional Development and Continuing Education Faculty of Educational Studies

Prepared by: Assoc. Prof. Dr Bahaman Abu Samah Department of Professional Development and Continuing Education Faculty of Educational Studies Prepared by: Assoc. Prof. Dr Bahaman Abu Samah Department of Professional Development and Continuing Education Faculty of Educational Studies Universiti Putra Malaysia Serdang At the end of this session,

More information

CHAPTER 3 RESEARCH METHODOLOGY

CHAPTER 3 RESEARCH METHODOLOGY CHAPTER 3 RESEARCH METHODOLOGY 3.1 Introduction 3.1 Methodology 3.1.1 Research Design 3.1. Research Framework Design 3.1.3 Research Instrument 3.1.4 Validity of Questionnaire 3.1.5 Statistical Measurement

More information

Appendix I. List of stakeholders consulted with on the Patient Radiation Protection Manual and members of the Medical Exposure Radiation Unit

Appendix I. List of stakeholders consulted with on the Patient Radiation Protection Manual and members of the Medical Exposure Radiation Unit References References The accuracy, quality and relevance of these works are not guaranteed or uniform and more recent information may have superseded these works. This list is not exhaustive. It does

More information

Review. Imagine the following table being obtained as a random. Decision Test Diseased Not Diseased Positive TP FP Negative FN TN

Review. Imagine the following table being obtained as a random. Decision Test Diseased Not Diseased Positive TP FP Negative FN TN Outline 1. Review sensitivity and specificity 2. Define an ROC curve 3. Define AUC 4. Non-parametric tests for whether or not the test is informative 5. Introduce the binormal ROC model 6. Discuss non-parametric

More information

LUNG CANCER continues to rank as the leading cause

LUNG CANCER continues to rank as the leading cause 1138 IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 24, NO. 9, SEPTEMBER 2005 Computer-Aided Diagnostic Scheme for Distinction Between Benign and Malignant Nodules in Thoracic Low-Dose CT by Use of Massive

More information

Improving Reading Time of Digital Breast Tomosynthesis with Concurrent Computer Aided Detection

Improving Reading Time of Digital Breast Tomosynthesis with Concurrent Computer Aided Detection White Paper Improving Reading Time of Digital Breast Tomosynthesis with Concurrent Computer Aided Detection WHITE PAPER 2 3 Abstract PowerLook Tomo Detection, a concurrent computer-aided detection (CAD)

More information

EVALUATION AND COMPUTATION OF DIAGNOSTIC TESTS: A SIMPLE ALTERNATIVE

EVALUATION AND COMPUTATION OF DIAGNOSTIC TESTS: A SIMPLE ALTERNATIVE EVALUATION AND COMPUTATION OF DIAGNOSTIC TESTS: A SIMPLE ALTERNATIVE NAHID SULTANA SUMI, M. ATAHARUL ISLAM, AND MD. AKHTAR HOSSAIN Abstract. Methods of evaluating and comparing the performance of diagnostic

More information

Measuring mathematics anxiety: Paper 2 - Constructing and validating the measure. Rob Cavanagh Len Sparrow Curtin University

Measuring mathematics anxiety: Paper 2 - Constructing and validating the measure. Rob Cavanagh Len Sparrow Curtin University Measuring mathematics anxiety: Paper 2 - Constructing and validating the measure Rob Cavanagh Len Sparrow Curtin University R.Cavanagh@curtin.edu.au Abstract The study sought to measure mathematics anxiety

More information

International Journal on Future Revolution in Computer Science & Communication Engineering ISSN: Volume: 4 Issue:

International Journal on Future Revolution in Computer Science & Communication Engineering ISSN: Volume: 4 Issue: Application of the Variance Function of the Difference Between two estimated responses in regulating Blood Sugar Level in a Diabetic patient using Herbal Formula Karanjah Anthony N. School of Science Maasai

More information

Readings: Textbook readings: OpenStax - Chapters 1 13 (emphasis on Chapter 12) Online readings: Appendix D, E & F

Readings: Textbook readings: OpenStax - Chapters 1 13 (emphasis on Chapter 12) Online readings: Appendix D, E & F Readings: Textbook readings: OpenStax - Chapters 1 13 (emphasis on Chapter 12) Online readings: Appendix D, E & F Plous Chapters 17 & 18 Chapter 17: Social Influences Chapter 18: Group Judgments and Decisions

More information

5/20/ Administration & Analysis of Surveys

5/20/ Administration & Analysis of Surveys 5/20/2015-1 Administration & Analysis of Surveys Goals Considerations when Administering Surveys Statistical Analysis of Surveys Examples of Reporting Survey Data 5/20/2015-2 Accuracy of Survey Data is

More information

Comparison of the Null Distributions of

Comparison of the Null Distributions of Comparison of the Null Distributions of Weighted Kappa and the C Ordinal Statistic Domenic V. Cicchetti West Haven VA Hospital and Yale University Joseph L. Fleiss Columbia University It frequently occurs

More information

Describe what is meant by a placebo Contrast the double-blind procedure with the single-blind procedure Review the structure for organizing a memo

Describe what is meant by a placebo Contrast the double-blind procedure with the single-blind procedure Review the structure for organizing a memo Please note the page numbers listed for the Lind book may vary by a page or two depending on which version of the textbook you have. Readings: Lind 1 11 (with emphasis on chapters 10, 11) Please note chapter

More information

Publishable JRP Summary Report for JRP HLT11 MetroMRT Metrology for Molecular Radiotherapy Background

Publishable JRP Summary Report for JRP HLT11 MetroMRT Metrology for Molecular Radiotherapy Background Publishable JRP Summary Report for JRP HLT11 MetroMRT Metrology for Molecular Radiotherapy Background The medical treatment modality of molecular radiotherapy (MRT), or nuclear medicine therapy, has been

More information

A Method for Statistical Process Control of Radiation Sterilization Facilities

A Method for Statistical Process Control of Radiation Sterilization Facilities A Method for Statistical Process Control of Radiation Sterilization Facilities 2006 A Method for Statistical Process Control (SPC) of Radiation Sterilization Facilities Scope This document describes a

More information

Evaluation of radiation dose and image quality following changes to tube potential (kvp) in conventional paediatric chest radiography

Evaluation of radiation dose and image quality following changes to tube potential (kvp) in conventional paediatric chest radiography Available online at http://www.biij.org/2006/3/e35 doi: 10.2349/biij.2.3.e35 biij Biomedical Imaging and Intervention Journal ORIGINAL PAPER Evaluation of radiation dose and image quality following changes

More information

The Fluoroscopic Technique for Monitoring Distraction of a Non-Invasive Lengthening Device in Early Onset Scoliosis

The Fluoroscopic Technique for Monitoring Distraction of a Non-Invasive Lengthening Device in Early Onset Scoliosis Send Orders for Reprints to reprints@benthamscience.net Open Medicine Journal, 2014, 1, 23-28 23 Open Access The Fluoroscopic Technique for Monitoring Distraction of a Non-Invasive Lengthening Device in

More information

Reveal Relationships in Categorical Data

Reveal Relationships in Categorical Data SPSS Categories 15.0 Specifications Reveal Relationships in Categorical Data Unleash the full potential of your data through perceptual mapping, optimal scaling, preference scaling, and dimension reduction

More information

Seesaw Balancing Radiation Dose and IV Contrast Dose: Evaluation of a New Abdominal CT Protocol for Reducing Age-Specific Risk

Seesaw Balancing Radiation Dose and IV Contrast Dose: Evaluation of a New Abdominal CT Protocol for Reducing Age-Specific Risk Medical Physics and Informatics Original Research CT Risk Reduction Medical Physics and Informatics Original Research Tobias Fält 1 Marcus Söderberg 2 Lisa Hörberg 1 Ingela Carlgren 1 Peter Leander 1 Fält

More information

Papers Arising from the Vertebral Artery Study

Papers Arising from the Vertebral Artery Study Papers Arising from the Vertebral Artery Study 1. Brief Introduction to quaternions and framed vectors and their application to the description of anatomical movements. The mathematical description of

More information

Conclusions and future directions

Conclusions and future directions Chapter 9 Conclusions and future directions This chapter summarises the findings within this thesis, examines its main contributions, and provides suggestions for further directions. 9.1 Thesis summary

More information

CHAPTER VI RESEARCH METHODOLOGY

CHAPTER VI RESEARCH METHODOLOGY CHAPTER VI RESEARCH METHODOLOGY 6.1 Research Design Research is an organized, systematic, data based, critical, objective, scientific inquiry or investigation into a specific problem, undertaken with the

More information

Title: Breast Screen Reader Assessment Strategy (BREAST): UK Collaboration

Title: Breast Screen Reader Assessment Strategy (BREAST): UK Collaboration Susan Williams CoRIPS Research Grant 147 5000 awarded Title: Breast Screen Reader Assessment Strategy (BREAST): UK Collaboration Principle Aim The principal aim of the study is to evaluate the performance

More information

Multislice CT versus cone beam CT: dosimetric and image quality comparision.

Multislice CT versus cone beam CT: dosimetric and image quality comparision. Multislice CT versus cone beam CT: dosimetric and image quality comparision. Poster No.: C-2589 Congress: ECR 2015 Type: Authors: Scientific Exhibit C. Dionisi 1, A. Crispo 2, E. Stefani 3, A. Lovaglio

More information

A Critique of Two Methods for Assessing the Nutrient Adequacy of Diets

A Critique of Two Methods for Assessing the Nutrient Adequacy of Diets CARD Working Papers CARD Reports and Working Papers 6-1991 A Critique of Two Methods for Assessing the Nutrient Adequacy of Diets Helen H. Jensen Iowa State University, hhjensen@iastate.edu Sarah M. Nusser

More information

Unit 1 Exploring and Understanding Data

Unit 1 Exploring and Understanding Data Unit 1 Exploring and Understanding Data Area Principle Bar Chart Boxplot Conditional Distribution Dotplot Empirical Rule Five Number Summary Frequency Distribution Frequency Polygon Histogram Interquartile

More information

Impact of digitalization of mammographic units on average glandular doses in the Flemish Breast Cancer Screening Program

Impact of digitalization of mammographic units on average glandular doses in the Flemish Breast Cancer Screening Program Impact of digitalization of mammographic units on average glandular doses in the Flemish Breast Cancer Screening Program An De Hauwere, Hubert Thierens Ghent University, Department of Medical Physics,

More information

A VIRTUAL TRAINING SYSTEM FOR CHEST RADIOGRAM INTERPRETATIONS USING ANATOMICAL HUMAN STRUCTURES IN HIGH-RESOLUTION CT IMAGES

A VIRTUAL TRAINING SYSTEM FOR CHEST RADIOGRAM INTERPRETATIONS USING ANATOMICAL HUMAN STRUCTURES IN HIGH-RESOLUTION CT IMAGES A VIRTUAL TRAINING SYSTEM FOR CHEST RADIOGRAM INTERPRETATIONS USING ANATOMICAL HUMAN STRUCTURES IN HIGH-RESOLUTION CT IMAGES T. Hara*, X. Zhou*, H. Fujita*, I. Kurimoto*, T. Kiryu**, R. Yokoyama**, H.

More information

CLINICAL AUDIT OF IMAGE QUALITY IN RADIOLOGY USING VISUAL GRADING CHARACTERISTICS ANALYSIS

CLINICAL AUDIT OF IMAGE QUALITY IN RADIOLOGY USING VISUAL GRADING CHARACTERISTICS ANALYSIS CLINICAL AUDIT OF IMAGE QUALITY IN RADIOLOGY USING VISUAL GRADING CHARACTERISTICS ANALYSIS Erik Tesselaar, Nils Dahlström and Michael Sandborg Linköping University Post Print N.B.: When citing this work,

More information

economic impact of the roslin institute - Executive Summary Executive Summary by BiGGAR Economics

economic impact of the roslin institute - Executive Summary Executive Summary by BiGGAR Economics ECONOMIC IMPACT OF THE ROSLIN INSTITUTE Executive Summary by BiGGAR Economics 1 executive summary ECONOMIC IMPACT OF THE ROSLIN INSTITUTE 2011/12 293 staff 142 post-graduate students 25.4 million funding

More information

Still important ideas

Still important ideas Readings: OpenStax - Chapters 1 13 & Appendix D & E (online) Plous Chapters 17 & 18 - Chapter 17: Social Influences - Chapter 18: Group Judgments and Decisions Still important ideas Contrast the measurement

More information

Chapter 1: Introduction to Statistics

Chapter 1: Introduction to Statistics Chapter 1: Introduction to Statistics Variables A variable is a characteristic or condition that can change or take on different values. Most research begins with a general question about the relationship

More information

MEASUREMENT OF THE EQUIVALENT INDIVIDUAL DOSES FOR PATIENTS IN ANGIOGRAPHY PROCEDURE AND INTERVENTIONAL RADIOLOGY WITH THERMOLUMINESCENT SYSTEMS

MEASUREMENT OF THE EQUIVALENT INDIVIDUAL DOSES FOR PATIENTS IN ANGIOGRAPHY PROCEDURE AND INTERVENTIONAL RADIOLOGY WITH THERMOLUMINESCENT SYSTEMS RADIOPROTECTION AND DOSIMETRY MEASUREMENT OF THE EQUIVALENT INDIVIDUAL DOSES FOR PATIENTS IN ANGIOGRAPHY PROCEDURE AND INTERVENTIONAL RADIOLOGY WITH THERMOLUMINESCENT SYSTEMS DANIELA ADAM 1, ANA STOCHIOIU

More information

Readings: Textbook readings: OpenStax - Chapters 1 11 Online readings: Appendix D, E & F Plous Chapters 10, 11, 12 and 14

Readings: Textbook readings: OpenStax - Chapters 1 11 Online readings: Appendix D, E & F Plous Chapters 10, 11, 12 and 14 Readings: Textbook readings: OpenStax - Chapters 1 11 Online readings: Appendix D, E & F Plous Chapters 10, 11, 12 and 14 Still important ideas Contrast the measurement of observable actions (and/or characteristics)

More information

Chapter 6. Hester Gietema Cornelia Schaefer-Prokop Willem Mali Gerard Groenewegen Mathias Prokop. Accepted for publication in Radiology

Chapter 6. Hester Gietema Cornelia Schaefer-Prokop Willem Mali Gerard Groenewegen Mathias Prokop. Accepted for publication in Radiology Chapter 6 Interscan variability of semiautomated volume measurements in intraparenchymal pulmonary nodules using multidetector-row computed tomography: Influence of inspirational level, nodule size and

More information

Model-based quantification of the relationship between age and anti-migraine therapy

Model-based quantification of the relationship between age and anti-migraine therapy 6 Model-based quantification of the relationship between age and anti-migraine therapy HJ Maas, M Danhof, OE Della Pasqua Submitted to BMC. Clin. Pharmacol. Migraine is a neurological disease that affects

More information

Table of Contents. Preface to the third edition xiii. Preface to the second edition xv. Preface to the fi rst edition xvii. List of abbreviations xix

Table of Contents. Preface to the third edition xiii. Preface to the second edition xv. Preface to the fi rst edition xvii. List of abbreviations xix Table of Contents Preface to the third edition xiii Preface to the second edition xv Preface to the fi rst edition xvii List of abbreviations xix PART 1 Developing and Validating Instruments for Assessing

More information

Assessing the standard dose to standard patients for x-ray investigations

Assessing the standard dose to standard patients for x-ray investigations Assessing the standard dose to standard patients for x-ray investigations A. Almén and W. Leitz Swedish Radiation Protection Authority, SE-171 16 Stockholm, Sweden E-mail: anja.almen@ssi.se Abstract. The

More information

Medical Diagnostic Imaging

Medical Diagnostic Imaging Medical Diagnostic Imaging Laboratories Medical Diagnostic Imaging Lab Name Location Person in Charge Programs Served Courses Served Patient Care and Management (2) Introduction to MDI Radiographic Technique

More information

Mammography is a most effective imaging modality in early breast cancer detection. The radiographs are searched for signs of abnormality by expert

Mammography is a most effective imaging modality in early breast cancer detection. The radiographs are searched for signs of abnormality by expert Abstract Methodologies for early detection of breast cancer still remain an open problem in the Research community. Breast cancer continues to be a significant problem in the contemporary world. Nearly

More information

Investigating the robustness of the nonparametric Levene test with more than two groups

Investigating the robustness of the nonparametric Levene test with more than two groups Psicológica (2014), 35, 361-383. Investigating the robustness of the nonparametric Levene test with more than two groups David W. Nordstokke * and S. Mitchell Colp University of Calgary, Canada Testing

More information

Reporting Checklist for Nature Neuroscience

Reporting Checklist for Nature Neuroscience Corresponding Author: Manuscript Number: Manuscript Type: Alex Pouget NN-A46249B Article Reporting Checklist for Nature Neuroscience # Main Figures: 7 # Supplementary Figures: 3 # Supplementary Tables:

More information

TACKLING WITH REVIEWER S COMMENTS:

TACKLING WITH REVIEWER S COMMENTS: TACKLING WITH REVIEWER S COMMENTS: Comment (a): The abstract of the research paper does not provide a bird s eye view (snapshot view) of what is being discussed throughout the paper. The reader is likely

More information

Optimizing Imaging Quality and Radiation Dose by the Age-Dependent Setting of Tube Voltage in Pediatric Chest Digital Radiography

Optimizing Imaging Quality and Radiation Dose by the Age-Dependent Setting of Tube Voltage in Pediatric Chest Digital Radiography Original Article http://dx.doi.org/10.48/kjr.01.14.1.16 pissn 19-699 eissn 005-80 Korean J Radiol 01;14(1):16-11 Optimizing Imaging Quality and Radiation Dose by the Age-Dependent Setting of Tube Voltage

More information

Lecture Outline. Biost 517 Applied Biostatistics I. Purpose of Descriptive Statistics. Purpose of Descriptive Statistics

Lecture Outline. Biost 517 Applied Biostatistics I. Purpose of Descriptive Statistics. Purpose of Descriptive Statistics Biost 517 Applied Biostatistics I Scott S. Emerson, M.D., Ph.D. Professor of Biostatistics University of Washington Lecture 3: Overview of Descriptive Statistics October 3, 2005 Lecture Outline Purpose

More information

CHAPTER - 6 STATISTICAL ANALYSIS. This chapter discusses inferential statistics, which use sample data to

CHAPTER - 6 STATISTICAL ANALYSIS. This chapter discusses inferential statistics, which use sample data to CHAPTER - 6 STATISTICAL ANALYSIS 6.1 Introduction This chapter discusses inferential statistics, which use sample data to make decisions or inferences about population. Populations are group of interest

More information

Choosing the Correct Statistical Test

Choosing the Correct Statistical Test Choosing the Correct Statistical Test T racie O. Afifi, PhD Departments of Community Health Sciences & Psychiatry University of Manitoba Department of Community Health Sciences COLLEGE OF MEDICINE, FACULTY

More information

The Impact of Continuity Violation on ANOVA and Alternative Methods

The Impact of Continuity Violation on ANOVA and Alternative Methods Journal of Modern Applied Statistical Methods Volume 12 Issue 2 Article 6 11-1-2013 The Impact of Continuity Violation on ANOVA and Alternative Methods Björn Lantz Chalmers University of Technology, Gothenburg,

More information

Endobronchial Ultrasound in the Diagnosis & Staging of Lung Cancer

Endobronchial Ultrasound in the Diagnosis & Staging of Lung Cancer Endobronchial Ultrasound in the Diagnosis & Staging of Lung Cancer Dr Richard Booton PhD FRCP Lead Lung Cancer Clinician, Consultant Respiratory Physician & Speciality Director Manchester University NHS

More information

Assessing Functional Neural Connectivity as an Indicator of Cognitive Performance *

Assessing Functional Neural Connectivity as an Indicator of Cognitive Performance * Assessing Functional Neural Connectivity as an Indicator of Cognitive Performance * Brian S. Helfer 1, James R. Williamson 1, Benjamin A. Miller 1, Joseph Perricone 1, Thomas F. Quatieri 1 MIT Lincoln

More information

1 Introduction. st0020. The Stata Journal (2002) 2, Number 3, pp

1 Introduction. st0020. The Stata Journal (2002) 2, Number 3, pp The Stata Journal (22) 2, Number 3, pp. 28 289 Comparative assessment of three common algorithms for estimating the variance of the area under the nonparametric receiver operating characteristic curve

More information

Still important ideas

Still important ideas Readings: OpenStax - Chapters 1 11 + 13 & Appendix D & E (online) Plous - Chapters 2, 3, and 4 Chapter 2: Cognitive Dissonance, Chapter 3: Memory and Hindsight Bias, Chapter 4: Context Dependence Still

More information

HOW STATISTICS IMPACT PHARMACY PRACTICE?

HOW STATISTICS IMPACT PHARMACY PRACTICE? HOW STATISTICS IMPACT PHARMACY PRACTICE? CPPD at NCCR 13 th June, 2013 Mohamed Izham M.I., PhD Professor in Social & Administrative Pharmacy Learning objective.. At the end of the presentation pharmacists

More information

Texas A&M College of Dentistry Oral and Maxillofacial Radiology

Texas A&M College of Dentistry Oral and Maxillofacial Radiology Texas A&M College of Dentistry Oral and Maxillofacial Radiology The college offers a graduate education program in Oral and Maxillofacial Radiology (OMR) that is accredited by the Commission on Dental

More information

How the brain works. ABSTRACT This paper analyses the associative capabilities of the brain and takes the consequences of that capability.

How the brain works. ABSTRACT This paper analyses the associative capabilities of the brain and takes the consequences of that capability. How the brain works By Ir J.A.J. van Leunen Retired physicist & software researcher Location: Asten, the Netherlands Website: www.scitech.nl Communicate your comments to info at that site. ABSTRACT This

More information

Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta GA, USA.

Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta GA, USA. A More Intuitive Interpretation of the Area Under the ROC Curve A. Cecile J.W. Janssens, PhD Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta GA, USA. Corresponding

More information

Quality of Life. The assessment, analysis and reporting of patient-reported outcomes. Third Edition

Quality of Life. The assessment, analysis and reporting of patient-reported outcomes. Third Edition Quality of Life The assessment, analysis and reporting of patient-reported outcomes Third Edition PETER M. FAYERS Institute of Applied Health Sciences, University ofaberdeen School of Medicine and Dentistry,

More information

An empirical approach to optimal experimental design selection and data analysis for the synthesis phase of Kansei Engineering

An empirical approach to optimal experimental design selection and data analysis for the synthesis phase of Kansei Engineering An empirical approach to optimal experimental design selection and data analysis for the synthesis phase of Kansei Engineering Antonio Lanzotti, Pietro Tarantino, Giovanna Matrone University of Naples

More information

Quality Assurance and Optimization of Radiation Protection of Patients in X-Ray Radiographic Examinations Using the Rejects Film Analysis

Quality Assurance and Optimization of Radiation Protection of Patients in X-Ray Radiographic Examinations Using the Rejects Film Analysis 60 Journal of Radiology and Diagnostic Imaging, 2013, 1, 60-64 Quality Assurance and Optimization of Radiation Protection of Patients in X-Ray Radiographic Examinations Using the Rejects Film Analysis

More information

INTRODUCTION TO DICOM FOR THE PRACTICING VETERINARIAN

INTRODUCTION TO DICOM FOR THE PRACTICING VETERINARIAN INTRODUCTION TO DICOM FOR THE PRACTICING VETERINARIAN MATTHEW A. WRIGHT, DENNIS BALLANCE, IAN D. ROBERTSON, BRIAN POTEET Digital Imaging and Communication in Medicine (DICOM) is a communication protocol

More information

ExperimentalPhysiology

ExperimentalPhysiology Exp Physiol 97.5 (2012) pp 557 561 557 Editorial ExperimentalPhysiology Categorized or continuous? Strength of an association and linear regression Gordon B. Drummond 1 and Sarah L. Vowler 2 1 Department

More information

A MONTE CARLO STUDY OF MODEL SELECTION PROCEDURES FOR THE ANALYSIS OF CATEGORICAL DATA

A MONTE CARLO STUDY OF MODEL SELECTION PROCEDURES FOR THE ANALYSIS OF CATEGORICAL DATA A MONTE CARLO STUDY OF MODEL SELECTION PROCEDURES FOR THE ANALYSIS OF CATEGORICAL DATA Elizabeth Martin Fischer, University of North Carolina Introduction Researchers and social scientists frequently confront

More information

Analysis of TB prevalence surveys

Analysis of TB prevalence surveys Workshop and training course on TB prevalence surveys with a focus on field operations Analysis of TB prevalence surveys Day 8 Thursday, 4 August 2011 Phnom Penh Babis Sismanidis with acknowledgements

More information

Radiation exposure of the Yazd population from medical conventional X-ray examinations

Radiation exposure of the Yazd population from medical conventional X-ray examinations Iran. J. Radiat. Res., 2007; 4 (4): 195-200 Radiation exposure of the Yazd population from medical conventional X-ray examinations F. Bouzarjomehri 1*, M.H. Dashti 2, M.H. Zare 1 1 Department of Medical

More information

Lecture Outline. Biost 590: Statistical Consulting. Stages of Scientific Studies. Scientific Method

Lecture Outline. Biost 590: Statistical Consulting. Stages of Scientific Studies. Scientific Method Biost 590: Statistical Consulting Statistical Classification of Scientific Studies; Approach to Consulting Lecture Outline Statistical Classification of Scientific Studies Statistical Tasks Approach to

More information

Receptor dose and Patient Dose in Radiographic exposures - a 15 year review

Receptor dose and Patient Dose in Radiographic exposures - a 15 year review Receptor dose and Patient Dose in Radiographic exposures - a 15 year review D J Peet*, N Tyler, M Pryor, P Hollaway, C Strudley and L Leavesley Regional Radiation Protection Service, Royal Surrey County

More information

Summary HTA. HTA-Report Summary

Summary HTA. HTA-Report Summary Summary HTA HTA-Report Summary Prognostic value, clinical effectiveness and cost-effectiveness of high sensitivity C-reactive protein as a marker in primary prevention of major cardiac events Schnell-Inderst

More information

Decisions based on verbal probabilities: Decision bias or decision by belief sampling?

Decisions based on verbal probabilities: Decision bias or decision by belief sampling? Decisions based on verbal probabilities: Decision bias or decision by belief sampling? Hidehito Honda (hitohonda.02@gmail.com) Graduate School of Arts and Sciences, The University of Tokyo 3-8-1, Komaba,

More information

Fundamentals of Breast Tomosynthesis

Fundamentals of Breast Tomosynthesis Fundamentals of Breast Tomosynthesis Improving the Performance of Mammography Andrew Smith, Ph.D. This white paper is one in a series of research overviws on advanced technologies in women s healthcare.

More information

Radiation Exposure and Image Quality in X-Ray Diagnostic Radiology

Radiation Exposure and Image Quality in X-Ray Diagnostic Radiology Horst Aichinger Joachim Dierker Sigrid Joite-Barfuß Manfred Säbel Radiation Exposure and Image Quality in X-Ray Diagnostic Radiology Physical Principles and Clinical Applications Second Edition Springer

More information