Ιστότοπος Ποιότητας στην Υγεία

Σάββατο, 14 Ιουνίου 2014 03:00

Evidence Based Radiology. A Multiple Choice Question Approach (Athanasios N. Chalazonitis)

Βαθμολογήστε αυτό το άρθρο
(0 ψήφοι)

 Athanasios N. Chalazonitis MD, MPH, PhD - Cordinator Director - Radiology Department, “Alexandra” General Hospital" - Athens Greece



The complexity of Radiology today is the result of the introduction of many revolutionary technologic developments in imaging during the past 3 decades. [1]

Today's challenge for Radiologists is to keep up to date with the rapidly expanding volume of medical knowledge and to learn how to acquire, interpret, and apply this knowledge appropriately. [2] Not only for Radiologists but also for clinicians, limited skills in appraising the scientific literature can be a substantial problem, as can Iimited expertise in integrating research evidence with medical practice. [3, 4]

Evidence-based Medicine (EBM) integrates clinical experience and patient values with the best available research information in order to expand research evidence and to provide sensible answers of medical questions in clinical decision making. It has blossomed into a multidimensional concept that is evolving to respond better to the needs of patients and the health professionals looking after them. The future holds promise for improved primary research, better EBM summaries, greater access to these summaries, and better implementation systems for Evidence-based practice. [5]



Question 1: When Evidence-Based Medicine’s history started?

A. B.C.

B. 17th Century.

C. Early 80’s.

D. Early 90’s.


Correct Answer: A

Hippocrates (460-377 B.C.) “the Father of Medicine”, was an ancient Greek physician considered as the first one who approached the importance of evidence in every day clinical practice. Hippocrates established the first philosophic definition for Evidence-Based Medicine, suggesting his physician students: “Των δ’ ως λόγου μόνου ξυμπεραινομένων μη είη έπαύρασθαι, των δε ως έργου ενδείξιος”; and in modern Greek: “Μη βασίζεστε σε συμπεράσματα που προκύπτουν μόνο από τη λογική, αλλά που αποδεικνύονται έμπρακτα”; and inmodernGreek: “Μηβασίζεστεσεσυμπεράσματαπουπροκύπτουνμόνοαπότηλογικήαλλάπουαποδεικνύονταιέμπρακτα”. And in English translation:“Do not rely on conclusions that arise from the mind, but from conclusions from action after evaluating the performance”. [6]

In the early 1990’s, a group of physician-epidemiologists in McMaster University in Canada developed a system, become known the term “Evidence-Based Medicine”. These doctors developed ways of efficiently tracking down and appraising literature and “wrote them up” in order to help other doctors, with no or with minimal formal epidemiological training. [7]

The first references to the practice of ΕΒΜ appeared inJAMA in 1993. [8,9] Then, in 1996, Sackett et al formally introduced the term “Evidence-based Medicine” to the medical community. [10] Ιn 1997 in The Lancet the first paper concerning evidence-based practice in the field of radiology had been published entitled “Medicine in the 21st Century”. [11] In 1999 the second paper about EBM and Radiology was published in Radiology. [12] Finally, in 2001, a review published in Radiology as well, entitled “Eνidence Based Radiology (EBR): Α New Approach to the Practice of Radiology," written by the Evidence-Based Radiology Working Group outlined the concept of ΕΒΜ within the field of radiology. [2]

Although the concept of EBM took a few years to be established, today ΕΒΜ has become an established component of the way we look after our patients. [5]



Question 2: Which is the correct definition for EBM?

A. EBM is an approach to health care that promotes the collection, interpretation, and integration of valid, important and applicable patient-reported, clinician-observed, and research-derived evidence.

B. EBM is the process ofsystematically finding, appraising, and using contemporaneousresearch findings as the basis for clinical decisions.

C. EBM is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.

D. All the above.

E. None of the above.


Correct Answer: D

EBM is an approach to health care that promotes the collection, interpretation, and integration of valid, important and applicable patient-reported, clinician-observed, and research-derived evidence. The best available evidence, moderated by patient circumstances and preferences, is applied to improve the quality of clinical judgments. [13]

EBM is the process ofsystematically finding, appraising, and using contemporaneousresearch findings as the basis for clinical decisions. It is also a habit that is recommended to all practicing radiologists so that they use the best logical thinking techniques to derive treatment plans. [7,14,15]

EBM is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research. [10]



Question 3: Which is the link between EBM and Radiology?

A. The integration of evaluative sciences and technology assessment into clinical practice.

B. The interpretation of imaging studies.

C. The use of Clinical Guidelines.

D. All the above.

E. None of the above.


Correct Answer: A

The integration of evaluative sciences and technology assessment into clinical practice. [2] Evidence-based Radiology is a relatively new approach to the practice of radiology based οn the principles of ΕΒΜ. [16] Evidence-based imaging is defined as medical decision making based on clinical integration of the best medical imaging research evidence with the physician’s expertise and with patient’s expectations. [1,12,17] Application of EBM principles to diagnostic imaging can facilitate the interpretation of imaging studies and create a well-conducted and effective radiologic evaluation. [6] Clinical implementation of imaging technology and imaging research outcomes requires stringent processes of governmental review and approval. Unfortunately in Radiology, is difficult to perform large Cohort studies, despite their observational nature, or prospective randomized control trials without funding and/or department financial or infrastructural support. [18]

In fact EBR allows the radiologist to look beyond individual patient outcome. The highest level of outcome is that of society, as measured by cost-effectiveness analysis (the method of estimating the value in terms of human health obtained for each dollar or euro on health care, permitting comparison of different imaging methods in medicine and thus may be a useful policy tool. [19]



Question 4: Which are the five steps in incorporating the best available research evidence in patient decision making?

A. Ask, Search, Appraise, Apply, Evaluate.

B. Ask, Investigate, Appraise, Apply, Evaluate.

C. Ask, Search, Appraise, Don’t Apply, Evaluate.

B. Ask, Category, Appraise, Apply, Evaluate.


Correct answer: A

EBM includes 5 basic steps that can be applied to any clinical discipline as well as to radiology[1,7,16,20,21]:

1st  Step. Ask. Formulate a practical answerable and focused clinical question.

2nd Step. Search. Find the best available information (evidence).

3rd Step. Appraisecritically the information for validity and relevance.

4th Step. Applythe information to patient care.

5th Step. Evaluate performance.



Question 5: How do we frame the clinical question?

A. As a single question.

B. In a two part form.

C. In a three part form.

D. In a four part form.


Correct answer: D

The inability to ask a focused and precise clinical question can be a major impediment to Evidence-based practice. This first step is the single more important one and requires careful thought. [21] The more detail incorporated into a clinical question, the more relevant the specific literature review becomes. [15]

The framework of this step, in order to formulate the clinical question works by accepting as follows that we may not know the proper answer.

EBM tools help to answer questions, which are specific and relevant to clinical decision making. [22] Other questions concerning basic biological processes, or “background”questions are better answered by standard textbooks.

Once the clinical question has been identified, it then needs to be put into a searchable and answerable four part form concerning [7, 23]:

  • The populationwith the clinical problem (how would I describe a group of patients similar to mine?)
  • An intervention or an exposure (which main intervention am I considering?)
  • The comparator intervention or exposure (what is the main alternative to compare with the intervention?)
  • The outcomes(what can I hope to accomplish? or what could this exposure really affect?)

This four-part question framework can be applied to all types of “foreground” questions asked by healthcare providers and consumers concerning [24]: 

  • Aetiology (why me?)
  • Prognosis (what will happen to me?)
  • Diagnosis(what is wrong with me?)
  • Intervention(how will intervention change outcome?)

In Diagnostic Radiology the main “foreground” questions EBM can address are related to the superiority of one imaging method over another in resolving clinical dilemmas and the power of imaging signs to reliably confirm or exclude suspected disease processes, in a particular population.

In Interventional Radiology, the main “foreground” questions are related to the short, medium and long-term benefit/harm of new interventional techniques compared with older interventional methods or more invasive surgical procedures.



Question 6How diagnostic Radiology questionscan be categorized?

A. Radiologic-pathologic correlation.

B. Comparison of imaging methods in a specific clinical condition.

C. Details about one imaging method in a specific clinical condition.

D. All the above.

E. None of the above.


Correct answer: D


 Question 7How interventional questions can be categorized?

A. Should a newer technique replace an older method? This is a benefit / harm analysis

B. How safe is a technique? Case series data can be used

C. Detail about the technical aspects of a technique in a specific clinical condition.

D. All the above.

E. None of the above.


Correct answer: D


Question 8: How do we search (access) to find the best available information (evidence) ?

A. In a valid form.

B. In a relevant form.

C. In a comprehensive form.

D. In a user-friendly form.

E. All the above.

F. None of the above.


Correct answer: E

The ideal information source must be [24]:

  • Valid (contains high quality data).
  • Relevant (clinically applicable).
  • Comprehensive (has data on all benefits and harms of all possible interventions).
  • User-friendly (quick and easy to access and use).

The most efficient type of search depends on the question being asked, while the best search strategy varies with the question and the operator.

Sources of information and evidence in clinical practice may include [21]:

  • Colleagues
  • Textbooks
  • Journal articles
  • Guidelines.



Question 9What is the “Evidence Pyramid”?

A. A three level ranking categorization of the reliability of given information.

B. A four level ranking categorization of the reliability of given information.

C. An up down pyramid of reliable given information.

D. There is no such term in EBM.


Correct answer: B

Currently there are more than 50 radiological journals, and imaging research is also frequently published in journals from other medical specialities. Radiologists are often confronted with more literature and information than they can process. The great challenge is to shift through the literature that is identified and to select that which is appropriate. [21]

In Medicine, practical resources to support evidence-based health care decisions are rapidly evolving. This evolution is based on the concept of the “Evidence Pyramid”, described by B. Haynes. [25] The higher up the pyramid we go, the more reliable the information we get. In EBM terms, original published journal articles (“primary” literature), must be distinguished from evidence-based reviews (“secondary” literature).

  • Primary literature forms level 4 (the base) of the pyramid and includes:Level 4:(Original published journal articles or clinical studies)When relevant systematic reviews or evidence-based guidelines are unavailable, or if they fail the quick critical appraisal test outlined in the following section, the Radiologist needs to find primary research studies. We can search this level by using the free website for MEDLINE, PubMed.
  • Secondary literature forms the upper 3 levels and includes:Level 3:(Evidence-based reviewsreviews. The findings of these reviews are presented as answers to the clinical questions associated with a specific topic. However they tend to be evidence driven rather than question driven. [26]section of the Clinical Queries link, which allows users to select the content area and the type of question (therapy, diagnosis, aetiology or prognosis), from the PubMed sidebar. The program then automatically incorporates the methodological filters into the search. Secondary sources of information also include Databases, Guidelines, Gateways and some Search Engines that filter evidence according to quality and relevance.CATs) produced by their clinical members. Many CATs are now available on the web.Level 2:(Synopses). These combine systematic reviews and recent primary literature. They comprise online subscription-only journals like Evidence Based Medicine and the ACP Journal Club which extract the best current internal medicine literature using impeccable methodology and present it with a one-line, usable title and contextual comment from an expert in the field.Level 1: (Information Systems). These are at the apex of the pyramid. They integrate and summarize all relevant and important research about a clinical problem.

  Question 10: How many “levels of evidence” can be described?

A. Three.

B. Five.

C. Ten.

D. Fifteen.


Correct answer: B

According to “The Oxford Centre for Evidence-Based Medicine” an abbreviated form of the levels of evidence can be described as follows:1a. Systematic reviews with homogeneity (articles in which the authors have systematically searched for, appraised, and summarized all of the medical literature for a specific topic) or randomized controlled trials (articles in which the group of patients is randomized into an experimental group and a control group) [18].1b. Individual randomized controlled trials with arrow confidence interval. (Independent blind comparison of an appropriate spectrum of consecutive patients, all of whom have undergone both the diagnostic test and the reference standard) [21] 1c. All or none case-series (a treatment benefit where, previously, all patients died but now some survive, or previously some patients died but now all survive).2a. Systematic reviews or Cohort studies (a study that involves the identification of two groups-cohorts- of patients, one which did receive the exposure of interest, and one which did not, and following these cohorts forward for the outcome of interest).2b. Individual Cohort studies.2c. Outcomes researches (studies that evaluate the impact of health care on the health outcomes of patients and populations).3a. Systematic reviews of case-control studies (studies that involve identifying patients who have the outcome of interest and control patients without the same outcome, and looking to see if they had the exposure of interest).3b. Individual case-control studies. (non-consecutive study or independent blind comparison of an appropriate spectrum, but reference standard was not applied to all studied patients). [27]4. Case series (reports on series of patients with an outcome of interest).5. Expert opinion (without explicit critical appraisal, or based on physiology, bench research or "first principles"). [27]With the above described form, any Radiologist, can quickly assign a level of evidence to each article retrieved from PubMed. [28]

Question 11: Where the term “levels of evidence” is concerned?

A. Expert opinions and policies, available for Radiologists.

B. Consensus of experts approaches to specific clinical or Radiological problems.

C. Categorization of published medical articles according to their study design and methodology.

D. All the above.

E. None of the above. 

Correct answer: C


Practising Radiologists, feel that finding reliable, up-to-date evidence on current problems in radiology may be complex and daunting. When searching into the literature, the vast volume of information being published and the lack of training in how to separate the good studies from the weak ones are the most important problems for radiologists. [5]According to different clinical situations, Radiologists, have to cope with a simple question: what type of study would give us the best quality evidence for our specific problem? In order to answer this question we have to use the levels of evidence. These levels of evidence can be used to rank articles according to their study design and methodology.Therefore medical information published in the literature may be categorized in five main levels. [29] The Oxford Centre for Evidence-Based Medicine has developed a table of levels of evidence. With this table, one can quickly assign a level of evidence to each article retrieved from PubMed. [28] 

 Question 12: Which are the best search strategies for electronic databases?

A. Database organization.

B. MeSH headings.

C. Simple searching.

D. Limiting search results.

C. Increasing search results.

E. Citation searching.

F. Advanced searching.

G. All the above

I. None of the above. 

Correct answer: G

It is well known that in every day practice, there are many available effective sources of medical information. World Wide Web is a rich illimitable electronic source of information. However navigation in those unbounded spaces requires a quiver of valuable tools named “search engines”. Any radiological search depends on the strategy used. Several approaches can be presented in order to get the best and most effective information to establish a base for evidence-based practice. [30]

1. Database organization.Electronic databases are arranged so that each aspect of an article's citation (title, authors, year, journal, when it first appeared in the database, abstract etc.) forms a separate field or sub field within the database. Each field can be searched individually for a specific item, or for a combination of items.

2. MeSH headings.Medical Sub Headings or MeSH terms are used by Medline and other databases as an additional form of indexing. MeSH headings allow articles sharing a common subject to be grouped together. This searching technique minimizes the chance of missing an article οn a particular topic in cases that the topic is not mentioned in the title or abstract. MeSH headings have the disadvantage that the author or indexer may arbitrarily choose between appropriate terms.

3.Simple searching.The simplest level of a search can be performed by looking for individual terms, one at a time. Α more efficient method is to combine individual terms with three different operators: AND, OR and ΝΟΤ.AND: includes only articles appearing in both terms.OR: includes articles appearing in either term.ΝΟΤ: includes articles appearing in one term but not the other

4. Limiting search results.Searching often results in a large number of apparently relevant citations. Ιn this case a method of focusing down is required to limit the results. Some databases have a specific feature to allow you to do this (e.g. Medline), others will require manual limiting. Ιn either case there are a number of ways of limiting search results:4.1. Limit by date. If one may only be interested in relatively recent articles.4.2. Limit by publication type. Α good meta-analysis is often ideal to answer an ΕΒΜ question and can be specified as the publication type of interest.4.3. Limit by Language. Limiting by English Language is commonly done but runs the risk of missing evidence not published in English.4.4. Limit by study population. Age, gender and human/animal are all ways of further limiting results.

5. Increasing search results.Sometimes a search will be met with few or no relevant results. The strategy needs to be amplified in these cases:5.1. Explode results. Exploding a MeSH term does not refer to the damage frustrated searchers may inflict οn their errant computers but rather a method by which all terms below a given term in the MeSH hierarchy are searched as well as the individual term.5.2. Synonyms. Use different terms for the same thing and combine using the OR operator.5.3. Wild cards. These are characters such as *, # or ? which allow either individual letters or whole sections of words to be varied. This is particularly useful in the case of American spelling.5.4. Related articles. This is a feature of a growing number of databases where an automatic system will look for similar articles to the one of interest.

6. Citation searching.The web of science databases allows citation searches. These can be very useful for tracking down articles because they allow automatic searching of secondary citations (those cited by a particular work).

7. Advanced searching.In some instances οnly a particular kind of study will be of interest. Various search 'filters' can be used automatically.


Question 13: Is the searching process the same for Radiology residents and Radiology specialists ?

A. Yes

B. No


Correct answer: B

In Radiology the searching process requires different access to the relevant medical literature. For example, a radiology resident must learn radiologic anatomy and radiology techniques and understand how images are generated. These background knowledge gaps can be adequately addressed by studying relevant textbooks and attending tutorials given by staff radiologists. On the other hand staff radiologists’ background knowledge gaps occur when encounter rare or new pathologic conditions on images generated by means of familiar or unfamiliar imaging methods, thus a review of the recent literature is often needed to address these foreground knowledge gaps. [31]



Question 14: How do we appraise critically the information for validity and relevance ?

A. The Materials and Methods section of the article is assessed for the "validity" of the study.

B. The Results section is evaluated for the statistical "strength" of the study.

C. Both the above.

D. None of the above.


Correct answer: C

Having found the research information, the user then needs to critically appraise the study (or the studies). When an article from the diagnostic literature is appraised, two sections are evaluated. The Materials and Methods section of the article is assessed for the "validity" of the study, and the Results section is evaluated for the statistical "strength" of the study. [27]

Validity (freedom from bias) is a measure of how close a study result is to the truth. The following questions must be answered [32]:

  • Was the study free of bias?
  • Was it performed in an appropriate group of patients?
  • Was an independent gold standard used?
  • Were the results subsequently validated in an appropriate prospective group of patients?
  • Is enough detail included for the study to be replicated?
  • Is there any commercial influence in the study?

The (statistical) strength of a study is an expression of the statistical power of its results. The strength of evidence incorporates [24]:

  • Appropriateness of the study design
  • Quality of the study's design and reporting
  • Statistical precision of the results.


Question 15: What is the publication bias?

A. The tendency for negative results.

B. The tendency for negative results.

C. The tendency for negative results.

D. None of the above.


Correct answer: A

Bias is any tendency to influence the results of a trial (or their interpretation) other than the experimental should aim to minimize publication biasThe tendency for negative results to be unequally reported in the literature. The importance of a clear statement of inclusion criteria is that studies should be selected on the basis of these criteria (that is, any study that matches these criteria is included) rather than selecting the study on the basis of the results. [33]Especially for Radiology, one of the most important features is how to select the subjects for the evaluation of an imaging study. In general, because the results of research investigation will be applied to a specific clinical group, the selection of the subjects for the study should also reflect a specific clinical scenario. [18]


Question 16: Does medical publication always guarantee “quality” ?

A. Yes.

B. No.

Correct answer: B

Unfortunately, most of what is found in the medical literature is biased and incompletely reported, and would therefore forma a poor basis for medical practice [18]. So medical literature may be classified according to its quality level ranging from type 1, the highest quality, to type 5 the lowest. [21] This motion has given rise to the concept of a "hierarchy of evidence" [34], which provides a framework for ranking evidence. Thus the evidence level can be categorized as follows [1,35]:Type 1: (Ideal evidence). Controlled case series with an appropriate spectrum of consecutive patients, all of whom have undergone both diagnostic and reference standard tests. The systematic review must include at least one randomized controlled trial and a summary of all included studies. The evidence from such a review requires careful appraisal; if well done, such evidence is powerful.Type 2: (Strong evidence). Controlled case series either with non-consecutive patients or confined to a narrow spectrum of study individuals, all of whom have undergone both diagnostic and reference standard tests.Type 3: (Moderate evidence). Uncontrolled case series in an appropriate spectrum of consecutive patients but without a reference standard test used for comparison. Evidence in this category will only be included if no type 1 or 2 evidence is available.Type 4: (Weak evidence). Uncontrolled case series in which a reference standard was used; study of diagnostic accuracy efficacy; eχpert opinion without explicit critical appraisal. Economic analyses (cost-effectiveness studies) are also classified as type 4 evidence. Studies in this category will only be included if no type 1, 2, or 3 evidence is available.Type 5: (Very weak evidence). Case reports; study of technical efficacy of a new technology.


Question 17: Are there any checklists of quality items for systematic reviews, Evidence-based guidelines, randomised controlled trials for intervention questions, cross-sectional analytic studies for diagnosis questions, Cohort studies for prognosis questions?

A. Yes.

B. No. 


Correct answer: A [36]

1. Systematic reviews.

  • Was a comprehensive and explicit search strategy used?
  • Were the included studies assessed for quality?
  • Were the characteristics and results of the studies summarised appropriately?
  • Were sources of heterogeneity explained?

2. Evidence-based guidelines.

  • Was a comprehensive and explicit search strategy used?
  • Have all relevant interventions and outcomes been considered, covering both benefits and harms?
  • Is the level and quality of evidence for the recommendations given?
  • Do the recommendations explore the trade-off of benefit and harm according to the level of risk in different patient subgroups?

3. Randomised controlled trials for intervention questions.

  • Was allocation to treatment groups concealed from those responsible for recruiting the subjects?
  • Were all randomised participants included in the analysis?
  • Was there a blinded assessment of outcomes?

4. Cross-sectional analytic studies for diagnosis questions.

  • Was the test compared with a valid reference (gold) standard?
  • Were the test and reference standard measured independently?
  • Was the choice of patients assessed by the reference standard independent of the test results?

5.Cohort studies for prognosis questions.

  • Was there a representative sample of patients at a well defined point in the course of the disease?
  • Was follow-up sufficiently long and complete?
  • Were all potentially important prognostic factors assessed?



Question 18: How do we apply the research evidence to decision making?

A. Compare the patient's characteristics with the trial's inclusion or blockade criteria

B. Think of an alternative approach.

C. Both the above.

D. None of the above.


Correct answer: C

In order to apply findings into clinical practice any Radiologist must [37]:

Compare the patient's characteristics with the trial's inclusion or blockade criteria to determine whether the results of a trial of a treatment are applicable to any individual patient.

This approach may lead to treating some patients who may experience more harm than benefit. So we can think of an alternative approach.

1. Make a balance sheet of the benefits and harms of the intervention.

All outcomes (both beneficial and harmful) that are important to the patient and influenced by the intervention need to be considered.

2. From research data, quantify the likelihood of benefits and harms in relative terms.

To estimate this we need to know the average effect of the treatment from systematic reviews (or trials, if systematic reviews are not available) and whether the effect varies according to patient and disease factors or whether it is relatively constant and independent of these factors. The benefits and harms of interventions are generally best expressed in relative terms (such as relative risks).

3. Convert the relative benefits and harms into absolute terms for your patient using the patient's specific characteristics.

If the relative beneficial effect of treatment is stable across patients at different levels of risk from their disease, then those at greatest risk will have the most to gain from treatment, and those at least risk from their disease will have the least to gain.

4. Decide whether the benefits outweigh the harms.

Having listed all benefits and harms of an intervention and assigned some likelihood for each outcome based on research and individual patient data, the next step is to determine whether, on balance, the treatment is likely to do more good than harm.



Question 19: Does an imaging efficacy hierarchy exists:

A. Yes.

B. No.


Correct answer: A


The imaging efficacy hierarchy first proposed by Fryaback, early in the 90’s. [38] He presented an organizing structure for appraisal of the literature on efficacy of imaging. Under his model imaging efficacy can be thought of as occurring through a sequence of six steps or levels. Demonstration of efficacy at each lower level in this hierarchy is logically necessary, but not sufficient, to assure efficacy at higher levels. [18]

Level 1 concerns technical quality of the images. Measures: signal-to-noise ratio, resolution, absence of artifacts.

Level 2 addresses diagnostic ac curacy, sensitivity, and specificity associated with interpretation of the images. Measures: sensitivity, specificity, ROC curves.

Level 3 focuses on whether the information produces change in the referring physician's diagnostic thinking. Measures: pre-test and post-test probability, diagnostic certainty.

Level 4 concerns effect on the patient management plan. Measures: treatment plan, operative or medical treatment frequency.

Level 5 measures (or computes) effect of the information on patient outcomes. Measures: survival, quality-adjusted life years, health status.

Level 6 analyses examine societal costs and benefits of a diagnostic imaging technology. Measures: cost-effectiveness, analysis, cost-utility analysis.



Question 20: How do we evaluate perfοrmance ?

A. At frequent intervals.

B. By deciding whether any improvement is needed.

C. By auditing action of performance.

D. All the above.

E. None of the above.


Correct answer: D

Radiologists who incorporate EBR iηto their routine clinical practice must evaluate the approach at frequent intervals and decide whether any improvement is needed in any of the 4 steps discussed above. [34] The formal auditing of performance will show whether the EBR approach is improving patient care. [16]


Question 21: Besides the 4 standard questions (Ask, Access, Appraise, and Apply) asked to assess the validity inΕΒΜ, are there any additional questions for Radiologists?

A. Yes.

B. No.

Correct answer: A

Radiologists must ask the following specific questions [32]:

  • Has the imaging method been described in sufficient detail for it to be reproduced in your own department?
  • Have the imaging tests being evaluated and the gold-standard test been performed to the same degree of excellence?
  • Have "generations" of technology development within the same modality been adequately considered in the study design?


Question 22: Can EBM play a role to the screening debate?

A. Yes.

B. No.

 Correct answer: A

Screening is an intervention (history, examination or investigation) for the detection of previously unrecognized disease or disease risk factors in order to treat/modify the disease/risk factor thereby leading to an improved prognosis. So screening process can be evaluated by a Randomized Controlled Trial (RCT) most appropriately. However because of the nature (long natural history) of many of the diseases thought suitable for screening and because the large majority of people screened in such trials will be free from disease these trials are inevitably expensive and require long follow-up times and large numbers of people.Therefore correlation and observational (case-control and cohort) studies can be also used.Correlation studies can examine the relationship between disease rates and the frequency of screening for the disease within a population.Case-control studies can examine the frequency of screening in a group of patients with the disease and the frequency of screening in a matched control group (without the disease).Cohort studies can examine the fatality rate in those diagnosed at screening compared to those diagnosed following presentation with symptoms to assess whether there is a better prognosis in those diagnosed through screening.s lives. [39]  


Question 23: Which are the limitations of EBM and EBR?

A. EBR is relatively new to radiologists.

B. ΕΒR is not easily accessible.

C. ΕΒΜ favours interventions that attract commercial sponsorship.

D. ΕΒΜ misses important patient expériences.

E. ΕΒΜ is biased.

F. All the above.

G.  None of the above. 


Correct answer: F

There are several limitations to the evidence based clinical or radiological everyday practice. The key to integrating EBM into clinical practice is having it easily available and understanding its limitations. EBM helps in shaping, rather than making, clinical questions. [40]ðEBR is relatively new to radiologists and is not part of the radiology curriculum. Until recently radiologists did not focus on developing their appraisal skills and on hypothesis-driven research as sufficiently as their colleagues from other fields of medicine. [40]ðΕΒR is not easily accessible. Searching can be difficult and the best evidence may not be readily available despite internet-based search tools. Furthermore, the current usage of electronic databases is suboptimal, with patient data being scattered across multiple data sources such as hospital information systems, radiology information systems, and picture archiving and communication systems, making it difficult to provide comprehensive results. [17]It can be difficult to find good data on diagnostic questions. The reference textbooks available in many radiology reading rooms and libraries are often out of date. [41]ðΕΒΜfavours interventions that attract commercial sponsorship. ΕΒΜ is good for common disorders and for those that require a treatment or intervention that has a commercial application.ðΕΒΜmisses important patient expériences. The classic large treatment trials miss out on all sorts of experiences which patients have as a result of their treatment.ðΕΒΜ is biased. There is no question that ΕΒΜ is biased. The art of critical appraisal is to detect bias, determine whether it is influencing the results and, if so, in what direction. [40]    


Question 24: What is the future of EBM ?

A. Exciting

B. Dark

C. Senseless

D. Fair 

Correct answer: A

to grow and evolve into many different forms. In the near future technology will drive this change at a phenomenal pace and transform the things we are taught and the way we practice. [42] EMB be equipped to teach. Finally EBM will become part of the curriculum for health professionals and the general public. [17] 


 A list of online ΕΒΜ resources [5,30,43]:


1. ACR Imaging Network. Organization with the goal to generate information that will lengthen and improve the quality of the Iives of cancer patients; Web site includes a set of guidelines.

2. ACR Appropriateness Criteria. Set of frameworks to assist referring physicians and other providers in making the most appropriate imaging and treatment decision.

3. Agency for Healthcare research and quality, Evidence-based practise

4. Appraisal of Guidelines Research and Evaluation AGREE. An international collaboration of researchers and policy makers who work together to improve the quality of clinical guidelines.

5. Bandolier. This is a monthly compendium of a wide variety of ΕΒΜ topics from methodology to the latest reviews.

6. CAT Crawler. CATs (Critically Appraised Topics) are appraisal of the evidence found in response to a clinical question.

7. Centre for Evidence-Based Medicine. Center located at Oxford University; has a clinically appraised topic facility.

8. Cochrane Collaboration. International endeavour with researchers from different countries to systematically find, appraise, and review available evidence from randomized controlled trials.http://www.cochrane.orgWeb sites for individual Cochrane groups can be found at: http:/

9. Cochrane Library. Compendium of systematic reviews and randomised controlled trials.

10. Clinical Evidence. Clinical Evidence is a publication consisting of evidence οn the effectiveness of clinical interventions.

11. It provides free access to Cochrane and Medline.

12. DynaMed.Systematically surveys original research reports, journal review services, systematic review sources, drug information sources and guideline collections as well as accompanying letters, editorials or review article, selecting information based on relevance and validity.

13. Evidence Based Medicine. This consists of summaries of important biomedical articles together with structured critiques and is a joint publication between the ΒΜΑ and ACP journal club.

14. Evidence Based Online. Evidence-based medicine surveys a wide range of international medical journals applying strict criteria for the quality and validity of research.

15.Guideline websites. Provided by medical colleges or specialty groups.

16. ΗΤΑ.n everything it commissions.

17. InfoRetriever.Is a search engine that allows you to search multiple databases, including InfoPOEMs, Cochrane Database abstracts, selected guidelines, clinical decision rules, diagnostic test calculators and the complete "Griffith's 5-Minute Clinical Consult."

18. JAMA user's guides to the medical literature. JAMA series about all aspects of medical literature.

19. Journals scan. Contains articles from journals and web sites that provide evidence for treatment, diagnosis or prognosis of medical conditions.

20. Medline. PubMed provides free access tο Medline including publisher supplied citations which appear as soon as the article is ίn print. http://www.ncbi.nlm.nih.gοv/

21. National Electronic Library (NeLH). It provides a wealth of eνidence based information including access to Cochrane, Clinical Evidence and much more.

22. NHS Centre for Reviews and dissemination (NHS CRD). The publishers of effectiveness matters and much more.

23. NHS Economic Evaluation Database. This site contains structured abstracts of economic evaluations.

24.  NHMRC Guidelines toolkit. How to review, use, apply, implement  and communicate evidence.

25. Oxford-Centre for Evidence-based Medicine.

26. ScHARR Netting the Evidence Page. This contains a wealth of evidence based material including further information οn databases, search tools and useful software. It is an excellent link to other ΕΒΜ sources.http://www.nettingthe­

27. Translation sites. Sites such as allow instant translation via the web and can be useful in getting the gist of foreign language articles. 

ConclusionΙn ancient Greek: “Δύο γαρ, επιστήμη τε και δόξα, ων το μεν επίστασθαι ποιεί, το δε αγνοείν.“Η αληθινή γνώση και η απλή γνώμη είναι δύο διαφορετικά μεταξύ τους πράγματα το ένα γεννάει την επιστήμη, το άλλο την άγνοια.“True knowledge and opinion are two totally different thinks. The first gives birth to science,  meanwhile the second forms ignorance”.Hippocrates (460-377 B.C.). Medical Ethics. Chapter: Law, paragraph: 4.  



1. Sackett DL, Straus S, Richardson S, Rosenberg W, Haynes RB. Evidence-based Medicine: how to practice and teach EBM, 2nd ed. Edinburgh UK: Churchill Livingston, 2000.

2. Evidence-Based Radiology Working Group. Evidence-based radiology: a new approach to the practice of radiology. RadioIogy 2001;220(3):566­-575.

3. Hillman Β. Evidence-based radiology: a primer for referring clinicians and radioIogists to improve the appropriateness of medical imaging. AvaiIable at:

4. Rosenberg W, Donald Α. Evidence based medicine: an approach to clinical problem-solving. ΒΜJ  1995;310:1122-1126.

5. Jadad AR. Randomised controlled trials: a user's guide. London, UK: ΒΜJ Books; 1998.

6. Chalazonitis AN, Pavi E, Tsimitselis G, Tzovara J. Everything you want to know about Evidence-Based Medicine (EBM) but you were afraid to ask. 91th Scientific Assembly and Annual Meeting of the Radiological Society of North America 2005. Chicago 27/10-2/12/2005.

7. Chalazonitis ANTsimitselis GTzovara JMariolis AAlevizos APavi E. Evidence-based medicine and radiology. JBR-BTR 2007;90(4):294-301.

8. Guyatt GΗ, Sackett DL, Cook DJ. Users’ guides to the medical Iiterature. How to use an article about therapy or prevention. Are the results of the study valid? Evidence-Based Medicine Working Group. JAMA 1993; 270:2598-2601.

9. Oxman AD, Sackett DL, Guyatt GH. Users guides to the medical literature. How to get started. The Evidence-Based Medicine Working Group. JAMA 1993;270:2093-2095.

10. Sackett, DL, Rosenberg WS, Gray JA, Haynes BR, Richardson S. Evidence based medicine: what it is and what it isn't. BMJ 1996;312: 71-72.

11. Hillman BJ. Medical imaging in the 21st Century. Lancet 1997;350:731-733.

12. Wood ΒΡ. What's the evidence? Radiology 1999;213:635-637.

13.  Straus SESackett DLApplying evidence to the individual patient.Ann Oncol. 1999 Jan;10(1):29-32.

14.  Eisenberg JM. Ten lesions for evidence-based technology assessment. JAMA 1999; 282:1865–1869.

15.  Hoffrage U, Lindsey S, Hertwig R, et al. Medicine communicating statistical information. Science 2000; 290:2261–2262.

16.  Erturk SM, Ondategui-Parra S, Otero H, Ros PR. Evidence Based Radiology. J Am Coll RadioI2006;3:513-519.

17.  Evidence-Based Medicine Working Group. Evidence-based medicine: a new approach to reaching the practice of medicine. JAMA 1992;268: 2420-2425.

18.  Blackmore CC. Evidence-based Imaging. In: Radiology Business Practice. Yousem DM, Beauchamp NJ (eds). Philadelphia: Saunders, 2008, p.p.367-379.

19.  Minoshima S. Research Mission. In: Radiology Business Practise. Yousem DM, Beauchamp NJ (eds). Philadelphia: Saunders, 2008, p.58

20.  Medina S, Blackmore CC. Principles of Evidence-Based Imaging. In: Medina S, Blackmore CC (eds). Evidence-Based Imaging. US, Springer:2006;pp1-18.

21.  Zou KH, Fielding JR, Ontdateguri-Parra S. What Is Evidence-based medicine?. Acad Radiol 2004;11:127–133.

22.  Richardson WS, Wilson MC, Nishikawa J, Hayward RS. The well-built clinical question: a key to evidence-based decisions. ACP J Club 1995; 123: A12-A13.

23. Heneghan C, Badenoch D. Evidence-based Medicine Toolkit. BML Books. Blackwell Publishing 2006; p 3.

24. Craig JC, Irwig LM and Stockler MR. Evidence-based medicine: useful tools for decision making. MJA 2001; 174: 248-253.

25. Haynes RB. Of studies, syntheses, synopses, and systems: the "4S" evolution of services for finding current best evidence. ACP J Club 2001; 134(2): A11-A133.

26. Heneghan C, Badenoch D. Evidence-based Medicine Toolkit. BMJ Books, Blackwell Publishing, 2nd Edition:2006;pp11.

27. Dodd JD. Evidence-based Practice in Radiology: Steps 3 and 4-Appraise and Apply Diagnostic Radiology Literature. Radiology 2007;242:342-354.

28. Levels of evidence. Oxford Centre for Evidence-Based Medicine

29. Heneghan C, Badenoch D. Evidence-based Medicine Toolkit. BMJ Books, Blackwell Publishing, 2nd Edition:2006;pp79-96.

30. McManus RJ. Sites of interest on the WWW. In: McGovern DPB, Valori RM, Summerskill WSM, Lavi M. (eds). Evidence-based medicine. Oxford, UK: BIOS 2001; pp 63-64.

31. Staunton M. Evidence-based Radiology: Steps 1 and 2—Asking Answerable Questions and Searching for Evidence. Radiology 2007;242:23-31.

32. Jaeschke R, Guyatt G, Sackett DL, Users' guides to the medical literature. III. How to use an article about a diagnostic test. A. Are the results of the study valid? Evidence-Based Medicine Working Group. Jama 1994; 271 (5):389-391.

33. Heneghan C, Badenoch D. Evidence-based Medicine Toolkit. BML Books. Blackwell Publishing 2006; pp 86-90.

34. Akobeng ΑΚ. Undersranding randomised conτtolIed trials. Arch Dis Child 2005;90:840-844.

35. Centre for Evidence-Based Medicine. Levels of evidence and grades of rec­ommendation. http://www.cebm.neι/ΙeveΙs_οf-eνίdence.asp.

36. Glasziou PP, Irwig LM. An evidence based approach to individualising treatment. BMJ 1995; 311: 1356-1359.

37. National Health and Medical Research Council. How to use the evidence: assessment and application of scientific evidence. Canberra: NHMRC, 2000.

38. Fryback DG, Thornbury JR. Med Decis Making199111 (2): 88-94.

39. McGovern DPB. Screening. In: McGovern DPB, Valori RM, Summerskill WSM, Lavi M. (eds). Key Topics. Evidence-Based Medicine. Oxford, UK: BIOS 2001; p 51.

40. Valori RM Limitations of EBM. In: McGovern DPB, Valori RM, Summerskill WSM, Lavi M. (eds). Evidence-based medicine. Oxford, UK: BIOS 2001; pp 149-150.

41. Bui AA, Taira RK, Dionisio JD, Aberle DR, El-Saden S, Kangarloo Η. Evidence-based radiology: requirements for electronic access. Acad Radiol 2002;9:662-669.

42. Valori RM. The future of EBM. In: McGovern DPB, Valori RM, Summerskill WSM, Lavi M. (eds). Key Topics. Evidence-based medicine. Oxford, UK: BIOS 2001; pp 151-152.

43. Heneghan C, Badenoch D. Evidence-based Medicine Toolkit. BML Books. Blackwell Publishing 2006; pp 86-90.


Διαβάστηκε 42287 φορές

Website Security Test