Method for Drafting and Approving New Pathways
The needs of differing groups of users are taken into consideration when deciding on which pathways should be developed. For general practitioners, pathways are considered for common clinical conditions (eg. hypertension, chronic headache), conditions which are complex in regard to the imaging modalities available (eg dyspepsia), conditions which are subject to inappropriate imaging (eg. plain radiographs of the lumbar spine for low back pain) and conditions which have new, more effective imaging options available (eg Magnetic Resonance Imaging). For hospital-based clinicians and medical students, additional pathways are developed for conditions involving acute presentations where immediate access to expert radiological opinion may be lacking (eg aspects of the acute abdomen, haemoptysis), and conditions for which there is a need for education (eg renal colic, imaging of pancreatitis). Additional pathways are developed after suggestions and feedback from general practitioners, specialist physicians, surgeons, and radiologists.
After approval of pathway development by the Editor, a systematic literature search strategy adapted from the NHS Centre for Reviews and Dissemination at the University of York is used to search Medline and PubMed databases for relevant medical literature. Initially all studies with potentially relevant articles regarding diagnosis are retrieved. From these available studies, case-reports, letters, and editorials are excluded. The next step involves identifying studies involving radiological investigations and studies relating to a particular clinical condition or undifferentiated symptom. By combining the sets with the term "AND", an initial pool of studies are acquired. Additional studies are identified by hand searching through available reference lists and by searching the Cochrane Database of Systematic Reviews.
Each study is graded using the Oxford Centre for Evidence-Based Medicine levels of evidence for diagnostic tests. Evidence is graded from Levels I to V, as follows:
- Level I: Validating cohort study with good reference standards or systematic review of validating cohort studies.
- Level II: Exploratory cohort study with good reference standards or systematic review of exploratory cohort studies.
- Level III: Non-consecutive study or without consistently applied reference standards.
- Level IV: Case control study, poor or non-independent reference standard.
- Level V: Expert opinion without explicit critical appraisal, or based on physiology, bench research or "first principles".
There is a paucity of systematic reviews on diagnostic imaging examinations. The majority of evidence falls into Levels II and III. Where necessary, review articles are referenced and these articles are marked 'Review article'.
A draft evidence-based guideline consisting of a flow chart, notes on imaging procedures and references is formulated by the Research Fellow and subsequently peer-reviewed by clinicians and radiologists. Based on the feedback received, the guideline is appropriately modified by the Editor and the Research Fellow. The modified-draft version is then submitted to an Editorial Panel consisting of radiologists and nuclear medicine physicians and their comments and feedback are incorporated into the published version of an imaging pathway.
The Vancouver standard of referencing is employed uniformly throughout each pathway. An internal link to the reference title is available by selecting the reference number within the medical-related text, which displays the reference title. The entire reference list for a given imaging pathway is accessible by a direct link from the main summary page. Any literature that has not been directly referred to but provides an excellent summary for the relevant clinical condition has been included under "Further reading". Each reference has been graded using the Oxford Centre of Evidence-Based Medicine levels of evidence (Level I to V), which has been provided at the end of each reference. Hyperlinks are available to the abstracts of all Level I and Level II evidence, in addition to articles that are deemed to be central to the development of an imaging pathway.
Under the current Australian health system, primary care physicians are unable to request Magnetic Resonance Imaging (MRI). The Editor has decided to include MRI in the Diagnostic Imaging Pathways where it is the most appropriate form of investigation. Where MRI is necessary, this should be an indication for specialist referral. In circumstances where adequate substitutes for MRI are available, they have been included.
Method for Reviewing and Revising Existing Pathways
Pathways are reviewed when literature becomes available to suggest that new imaging modalities or updated existing technology improve on the ability of current imaging techniques to detect disease. Systematic literature reviews are conducted periodically to identify the latest studies relevant to a given topic. In addition, communication with radiologists and clinicians enables the Editor and Research Fellow to keep abreast of current research presented at conferences, seminars and meetings that has not yet been published. All medical literature is graded using the Oxford Centre of Evidence Based Medicine, Levels of Evidence for diagnostic tests.
The pathways are appropriately updated and radiologist and clinician feedback is sought as outlined in the earlier section. All suggestions are incorporated into the published version of the guideline at the discretion of the Editor. All imaging pathways indicate the date of last modification, which is located on the summary page for that particular pathway.
Use of Established Guidelines
Internationally recognised, prospectively validated guidelines are available (eg Ottawa Ankle Rules, NEXUS cervical spine injury prediction rule) and where appropriate, have been incorporated into the Diagnostic Imaging Pathways. This decision is made in consultation with specialist physicians and surgeons, with regard to their preferred clinical practice and the practicality of the established guidelines. These publications, like all others which have been used to formulate the Diagnostic Imaging Pathways, are referenced in the Vancouver format and hyperlinks are available for viewing the abstract of the relevant article.
Last reviewed in May 2009.