Evidence-based medicine proposes safer and more effective interventions for patients based on the integration of evidence from research, the knowledge of clinical experts, and the values of patients. One way of implementing evidence-based medicine is through the use of clinical guidelines. Clinical guidelines are the literature that describe optimal clinical practice and help clinicians and patients to make decisions. These guidelines are considered to be effective at maintaining continuity of patients' care and narrowing the gap between scientific evidence and treatment. As an effort to improve the quality of medical services in recent decades, the development and application of these guidelines has been steadily increasing worldwide. In Korea, many academic societies and organizations have also developed clinical guidelines, and have been publishing them since 1997 (1).

In the field of radiology, individual developed countries are utilizing evidence-based clinical imaging guidelines (CIGs) in order to augment clinical decision-making by physicians when requesting or prescribing a radiologic examination. Because radiologic examinations often involve exposure to medical radiation, the principle of justification must be abided by to protect patients from medical radiation exposure: the benefits must outweigh the potential harm in all circumstances where patients are to be exposed, and clinicians should perform only necessary examinations. The action plan (known as the ‘Three As’) for the principle justifying the use of radiation includes ‘awareness’ of medical radiation exposure, ensuring the ‘appropriateness’ of examinations and procedures, and a retrospective ‘audit’. As a means of ensuring appropriateness, guidelines to support clinical referrals and decisions are being developed and applied to clinical treatment (23).

Evidence-based CIGs have been developed in many countries depending on the local circumstances. The iRefer of the Royal College of Radiologists (RCR) in the United Kingdom, Appropriateness Criteria® of the American College of Radiology (ACR) in the United States, and Diagnostic Imaging Pathways (DIP) in Western Australia have each developed their own guidelines (456). These clinical referral guidelines provide the relative dose level of radiation in examinations for various clinical conditions, along with other recommendations and expert opinions. The guidelines are periodically revised (7), and in the case of the Appropriateness Criteria® of the ACR in the United States, a decision-making system reflecting the most recent guidelines has been made accessible online (8). The DIP of Western Australia also supports clinical decision-making through a diagram available on their website (6). The above medical guidelines were created de novo, meaning that they were newly developed through a direct search and review of the available evidence. In contrast, many other countries with similar medical environments often modify, adopt, or translate clinical radiation guidelines that were previously created by the RCR and ACR (7).

In Korea, the need for radiological guidelines led to the development of ‘the CT Examination and Repeat CT Examination Guideline’ by collaboration of Health Insurance Review & Assessment Service and Korean Society of Radiology (KSR) (9), ‘the Guideline for Diagnosis and Management of Hepatocellular Carcinoma’ by Korean Liver Cancer Study Group (10), ‘the Guideline for Ultrasonographic Diagnosis and Image-Based Management of Thyroid Nodules’ by Korean Society of Thyroid Radiology (11), ‘Korean Guideline for Interventional Recanalization of Lower Extremity Arteries’ by collaboration of multi-disciplinary societies including Korean Society of Interventional Radiology (12), and ‘the Guidelines for Appropriate Use of Cardiac CT in Heart Disease’ by the KSR, Korean Society of Cardiology, and National Strategic Coordinating Center of Clinical Research (1314). However, as there are still no CIGs that comprehensively support physicians to prescribe diagnostic and interventional radiologic procedures which are appropriately suited to the situation in Korea, the need for a Korean version of evidence-based clinical medical radiology guidelines has become paramount. Because of this, the development of the evidence-based CIGs has begun, led by the KSR and the National Evidence-Based Healthcare Collaborating Agency, along with the participation of clinical and methodology experts. They selected adaptation for the methodology of CIGs, which accepted developed guidelines and modified for a new guideline to be suited to the medical environment in Korea (15). As the previously existing guidelines in Korea focused mainly on therapeutic interventions, the practical development of manuals that instruct on developing guidelines for diagnostic examinations became a priority. For this reason, development manuals are being written alongside the guidelines (16).

Adaptation process of guidelines is based on internationally standardized adaptation methodology that is suggested by ADAPTE Collaboration (17). Then we modified adaptation process for working group's practice under consultation. Developing the Korean CIGs (K-CIGs) involved three stages, set-up (planning), adaptation process, and finalization (Fig. 1). The set-up stage (planning and composition) outlines a process to form committees and clarify their roles. The adaptation stage involves the stepwise development process to draft the guideline. The finalization stage includes the process of completing the recommendation document based on evidence, undergoing external review, and obtaining final approval. Also we developed a protocol for working group that including the process from adaptation to finalization as 8 stages for practical help (Table 1).

This paper is a summary of the methodology used in the development of evidence-based clinical radiology guidelines to support referral and clinical decisions, which strive to promote the use of only appropriate examinations and medical procedures, performed in optimal clinical conditions.

To develop evidence-based CIGs suitable for Korea, the “Methodology of K-CIG development” was established. The working group consisted of clinical imaging experts to ensure clinical expertise. The development committee consisted of multidisciplinary experts to ensure validity of the methodology and provide insight on the guideline development process. The development process was divided into several stages, and the two committees were able to collaborate with each other during various stages. In order to reflect the opinions of end-users, a consensus group composed of experts from medical societies was formed to accept their opinion during the development process.

This is the first evidence-based CIG in Korea, and it provides final recommendations and RRLs for radiologic examinations. Although not all decisions in different clinical settings can be made based on evidence, these guidelines will definitely assist in the decision-making process of clinicians in advance, who need to refer the patients for imaging examinations (19). Furthermore, this will justify the medical radiation exposure for patients, and eventually assist in ensuring safety from medical radiation exposure for the patients. Since the developmental process of K-CIGs was fully considered whether their recommendations are acceptable and applicable to the situation in Korea, we expect these guidelines will be widely used at real clinical fields.

Also, we hope to see this article will be utilized as a manual for the next development of CIGs in future, along with the ‘Methodology manual for development of K-CIG’ which is the first-ever in Korea to outline the development process of the guidelines about diagnostic examinations.