Radiology
Canadian Association of Radiologists
Last updated: June 2026
-
Red flags include suspected epidural abscess or hematoma presenting with acute pain, but no neurological symptoms (urgent imaging is required); suspected cancer; suspected infection; cauda equina syndrome; severe or progressive neurologic deficit; and suspected compression fracture. In patients with suspected uncomplicated herniated disc or spinal stenosis, imaging is only indicated after at least a six-week trial of conservative management and if symptoms are severe enough that surgery is being considered.
Sources:
American College of Radiology. ACR appropriateness criteria® low back pain. [Internet]. 2015 [cited 2017 May 5].
Bach SM, et al. Guideline update: What’s the best approach to acute low back pain? J Fam Pract. 2009 Dec;58(12):E1. PMID: 19961812.
Choosing Wisely. American Academy of Family Physicians (AAFP): Fifteen things physicians and patients should question [Internet]. 2012 [cited 12 mars 2014].
Chou R, et al. Imaging strategies for low-back pain: Systematic review and meta-analysis. Lancet. 2009 Feb 7;373(9662):463-72. PMID: 19200918.
Chou R, et al. Diagnostic imaging for low back pain: Advice for high-value health care from the American College of Physicians. Ann Intern Med. 2011 Feb 1;154(3):181-9. PMID: 21282698.
Goertz M, et al. Adult acute and subacute low back pain [Internet]. 2012 Nov [cited 2017 May 5].
Michigan Quality Improvement Consortium. Management of acute low back pain [Internet]. 2012 Sep [cited 2014 Feb 23].
National Collaborating Centre for Primary Care (UK). Low back pain: Early management of persistent non-specific low back pain. 2009 May. PMID: 20704057.
Toward Optimized Practice. Guideline for the evidence-informed primary care management of low back pain [Internet]. 2011 Nov [cited 2017 May 5].
University of Michigan Health System. Acute low back pain [Internet]. 2010 Jan [cited 2017 May 5].
van Rijn RM, et al. Computed tomography for the diagnosis of lumbar spinal pathology in adult patients with low back pain or sciatica: A diagnostic systematic review. Eur Spine J. 2012 Feb;21(2):228-39. PMID: 21915747.
Wassenaar M, et al. Magnetic resonance imaging for diagnosing lumbar spinal pathology in adult patients with low back pain or sciatica: A diagnostic systematic review. Eur Spine J. 2012 Feb;21(2):220-7. PMID: 21922287.
-
Red flags include Glasgow Coma Scale (GCS) less than 13; GCS less than 15 at 2 hours post-injury; a patient aged 65 years or older; obvious open skull fracture; suspected open or depressed skull fracture; any sign of basilar skull fracture (e.g., hemotympanum, raccoon eyes, Battle’s Sign, CSF otorhinorrhea); retrograde amnesia to the event lasting 30 minutes or longer after the event; “dangerous” mechanism (e.g., pedestrian struck by motor vehicle, occupant ejected from motor vehicle, or fall from higher than 3 feet or down more than 5 stairs); and coumadin-use or bleeding disorder.
Sources:
Davis PC, et al. ACR appropriateness criteria® head trauma [Internet]. 2015 [cited 2017 May 5].
Holmes MW, et al. The cost-effectiveness of diagnostic management strategies for adults with minor head injury. Injury. 2012 Sep;43(9):1423-31. PMID: 21835403.
Jagoda AS, et al. Clinical policy: Neuroimaging and decisionmaking in adult mild traumatic brain injury in the acute setting. Ann Emerg Med. 2008 Dec;52(6):714-48. PMID: 19027497.
Management of Concussion/mTBI Working Group. VA/DoD clinical practice guideline for management of concussion/mild traumatic brain injury (mTBI)]. J Rehabil Res Dev. 2009;46(6):CP1-68. PMID: 20108447.
Marshall S, et al. Clinical practice guidelines for mild traumatic brain injury and persistent symptoms. Can Fam Physician. 2012 Mar;58(3):257,67, e128-40. PMID: 22518895.
Motor Accidents Authority NSW (MAA). Guidelines for mild traumatic brain injury following closed head injury: Acute/post-acute assessment and management [Internet]. 2008 [cited 2017 May 5].
Ontario Neurotrauma Foundation. Guidelines for mild traumatic brain injury and persistent symptoms [Internet]. 2011 [cited 2017 May 5].
Pandor A, et al. Diagnostic management strategies for adults and children with minor head injury: A systematic review and an economic evaluation. Health Technol Assess. 2011 Aug;15(27):1-202. PMID: 21806873.
Pandor A, et al. Diagnostic accuracy of clinical characteristics for identifying CT abnormality after minor brain injury: A systematic review and meta-analysis. J Neurotrauma. 2012 Mar 20;29(5):707-18. PMID: 21806474.
Reed D. Adult trauma clinical practice guidelines: Initial management of closed head injury in adults [Internet]. 2011 Nov [cited 2017 May 5].
Scottish Intercollegiate Guidelines Network (SIGN). Early management of patients with a head injury: A national clinical guideline [Internet]. 2009 May [cited 2017 May 5].
Smits M, et al. Minor head injury: CT-based strategies for management–a cost-effectiveness analysis. Radiology. 2010 Feb;254(2):532-40. PMID: 20093524.
West TA, et al. Care of the patient with mild traumatic brain injury [Internet]. 2011 [cited 2017 May 5].
Work Loss Data Institute. Head (trauma, headaches, etc., not including stress & mental disorders) [Internet]. 2011 [cited 2017 May 5].
-
Red flags include recent onset, rapidly increasing frequency and severity of headache; headache causing the patient to wake from sleep; associated dizziness, lack of coordination, tingling or numbness, new neurologic deficit; and new onset of a headache in a patient with a history of cancer or immunodeficiency.
Sources:
Beithon J, et al. Institute for clinical systems improvement. Diagnosis and treatment of headache [Internet]. 2013 Jan [cited 2017 May 5].
Choosing Wisely. American College of Radiology: Five things physicians and patients should question [Internet]. 2012 Apr 4 [cited 2017 May 5].
Edlow JA, et al. Clinical policy: Critical issues in the evaluation and management of adult patients presenting to the emergency department with acute headache. Ann Emerg Med. 2008 Oct;52(4):407-36. PMID: 18809105.
Hayes LL, et al. ACR appropriateness criteria®: Headache – child [Internet]. 2012 [cited 2014 Feb 23].
Health Quality Ontario. Neuroimaging for the evaluation of chronic headaches: An evidence-based analysis. Ont Health Technol Assess Ser. 2010;10(26):1-57. PMID: 23074404.
Jordan YJ, et al. Computed tomography imaging in the management of headache in the emergency department: Cost efficacy and policy implications. J Natl Med Assoc. 2009 Apr;101(4):331-5. PMID: 19397223.
National Institute for Health and Clinical Excellence (NICE). Headaches: Diagnosis and management of headaches in young people and adults [Internet]. 2012 Sep [2017 May 5].
Sandrini G, et al. Neurophysiological tests and neuroimaging procedures in non-acute headache (2nd edition). Eur J Neurol. 2011 Mar;18(3):373-81. PMID: 20868464.
Scottish Intercollegiate Guidelines Network (SIGN). Diagnosis and management of headache in adults: A national clinical guideline [Internet]. 2008 Nov [2017 May 5].
Toward Optimized Practice. Guideline for primary care management of headache in adults [Internet]. 2016 Sep [2017 May 5].
-
Although CT is accurate in the evaluation of suspected appendicitis in the pediatric population, ultrasound is nearly as good in experienced hands. Since ultrasound will reduce radiation exposure, ultrasound is the preferred initial imaging examination in children. If the results of the ultrasound exam are equivocal, it may be followed by CT. This approach is cost-effective, reduces potential radiation risks and has excellent accuracy, with reported sensitivity and specificity of 94 percent.
Sources:
Adibe OO, et al. An evidence-based clinical protocol for diagnosis of acute appendicitis decreased the use of computed tomography in children. J Pediatr Surg. 2011 Jan;46(1):192-6. PMID: 21238665.
Bachur RG, et al. The effect of abdominal pain duration on the accuracy of diagnostic imaging for pediatric appendicitis. Ann Emerg Med. 2012 Nov;60(5):582,590.e3. PMID: 22841176.
Bachur RG, et al. Diagnostic imaging and negative appendectomy rates in children: Effects of age and gender. Pediatrics. 2012 May;129(5):877-84. PMID: 22508920.
Bachur RG, et al. Advanced radiologic imaging for pediatric appendicitis, 2005-2009: Trends and outcomes. J Pediatr. 2012 Jun;160(6):1034-8. PMID: 22192815.
Burr A, et al. Glowing in the dark: Time of day as a determinant of radiographic imaging in the evaluation of abdominal pain in children. J Pediatr Surg. 2011 Jan;46(1):188-91. PMID: 21238664.
Choosing Wisely. American College of Radiology: Five things physicians and patients should question [Internet]. 2013 [cited 2014 Mar 12].
Krishnamoorthi R, et al. Effectiveness of a staged US and CT protocol for the diagnosis of pediatric appendicitis: Reducing radiation exposure in the age of ALARA. Radiology. 2011 Apr;259(1):231-9. PMID: 21324843.
Park JS, et al. Accuracies of diagnostic methods for acute appendicitis. Am Surg. 2013 Jan;79(1):101-6. PMID: 23317620.
Ramarajan N, et al. An interdisciplinary initiative to reduce radiation exposure: Evaluation of appendicitis in a pediatric emergency department with clinical assessment supported by a staged ultrasound and computed tomography pathway. Acad Emerg Med. 2009 Nov;16(11):1258-65. PMID: 20053244.
Santillanes G, et al. Prospective evaluation of a clinical practice guideline for diagnosis of appendicitis in children. Acad Emerg Med. 2012 Aug;19(8):886-93. PMID: 22849662.
Thirumoorthi AS, et al. Managing radiation exposure in children–reexamining the role of ultrasound in the diagnosis of appendicitis. J Pediatr Surg. 2012 Dec;47(12):2268-72. PMID: 23217887.
Wan MJ, et al. Acute appendicitis in young children: Cost-effectiveness of US versus CT in diagnosis–a Markov decision analytic model. Radiology. 2009 Feb;250(2):378-86. PMID: 19098225.
-
X-rays are only indicated if there is pain in the malleolar zone, bone tenderness at the posterior edge or tip of either malleolus, or inability to bear weight for four steps immediately after the trauma and in the emergency department.
Sources:
Bennett DL, et al. ACR appropriateness criteria® acute trauma to the foot [Internet]. 2014 [cited 2017 May 5].
Blackham JE, et al. Can patients apply the ottawa ankle rules to themselves? Emerg Med J. 2008 Nov;25(11):750-1. PMID: 18955612.
Can U, et al. Safety and efficiency of the Ottawa ankle rule in a Swiss population with ankle sprains. Swiss Med Wkly. 2008 May 3;138(19-20):292-6. PMID: 18491243.
Dowling S, et al. Accuracy of Ottawa Ankle Rules to exclude fractures of the ankle and midfoot in children: a meta-analysis. Acad Emerg Med. 2009 Apr;16(4):277-87. PMID: 19187397.
Gravel J, et al. Prospective validation and head-to-head comparison of 3 ankle rules in a pediatric population. Ann Emerg Med. 2009 Oct;54(4):534,540.e1. PMID: 19647341.
Jenkin M, et al. Clinical usefulness of the Ottawa ankle rules for detecting fractures of the ankle and midfoot. J Athl Train. 2010 Sep-Oct;45(5):480-2. PMID: 20831394.
Knudsen R, et al. Validation of the Ottawa ankle rules in a Danish emergency department. Dan Med Bull. 2010 May;57(5):A4142. PMID: 20441713.
Lin CW, et al. Economic evaluations of diagnostic tests, treatment and prevention for lateral ankle sprains: A systematic review. Br J Sports Med. 2013 Dec;47(18):1144-9. PMID: 22554849.
National Guideline Clearinghouse. Guideline summary: Ankle and foot disorders [Internet]. 28 Oct 2013 [cited 5 May 2017].
Petscavage J, et al. Overuse of concomitant foot radiographic series in patients sustaining minor ankle injuries. Emerg Radiol. 2010 Jul;17(4):261-5. PMID: 19834751.
Polzer H, et al. Diagnosis and treatment of acute ankle injuries: Development of an evidence-based algorithm. Orthop Rev (Pavia). 2012 Jan 2;4(1):e5. PMID: 22577506.
Seah R, et al. Managing ankle sprains in primary care: What is best practice? A systematic review of the last 10 years of evidence. Br Med Bull. 2011;97:105-35. PMID: 20710025.
Wang X, et al. Clinical value of the Ottawa ankle rules for diagnosis of fractures in acute ankle injuries. PLoS One. 2013 Apr 30;8(4):e63228. PMID: 23646202.
Work Loss Data Institute. Guideline summary: Ankle & foot (acute & chronic). [Internet]. 2013 Oct 28 [cited May 5, 2017]
-
In adults with shoulder pain, if further investigation is required after the initial X-ray assessment, ultrasound is recommended as the next imaging modality for the evaluation of soft tissue pathology (such as rotator cuff tear, tendinopathy, effusion, bursitis, soft tissue calcification, or extra-articular impingement).
Sources:
Gorelik N, et al. Optimizing Musculoskeletal Imaging Referrals: Making Wise Choices a Knee-Jerk Reaction. Can Assoc Radiol J. 2025 May 26:8465371251339389. Epub ahead of print. PMID: 40420549.
Hamel C, et al. Canadian Association of Radiologists Musculoskeletal System Diagnostic Imaging Referral Guideline. Can Assoc Radiol J. 2024; 75(2):269-278. Epub 2023 Sep 27. PMID: 37635274.
Small KM, et al. ACR appropriateness criteria® shoulder pain-atraumatic. J Am Coll Radiol. 2018; 15(11S):S388-S402. PMID: 30392607.
Sconfienza LM, et al. Clinical indications for musculoskeletal ultrasound updated in 2017 by European Society of Musculoskeletal Radiology (ESSR) consensus. Eu Radiol. 2018;28(12):5338-5351. Epub 2018 Jun 6. PMID: 29876703.
The Royal College of Radiologists. RCR IRefer Guidelines: Making the Best Use of Clinical Radiology. London: The Royal College of Radiologists, [Internet]. 2017 [cited 2017].
Weber S, et al. Management of rotator cuff injuries. J Am Acad Orthop Surg. 2020;28(5):e193-e201. PMID: 31599763.
-
If x-ray demonstrates imaging findings that may predispose to femoroacetabular impingement (FAI), then consultation to a musculoskeletal specialist is suggested as MRI may neither be required nor advance diagnosis or management.
Sources:
Gorelik N, et al. Optimizing Musculoskeletal Imaging Referrals: Making Wise Choices a Knee-Jerk Reaction. Can Assoc Radiol J. 2025 May 26:8465371251339389. Epub ahead of print. PMID: 40420549.
Hamel C, et al. Canadian Association of Radiologists Musculoskeletal System Diagnostic Imaging Referral Guideline. Can Assoc Radiol J. 2024; 75(2):269-278. Epub 2023 Sep 27. PMID: 37635274.
Jawetz ST, et al. ACR Appropriateness Criteria® Chronic Hip Pain: 2022 Update. J Am Coll Radiol. 2023; 20(5): S33-S48. PMID: 37236751.
Mascarenhas VV, et al. The Lisbon Agreement on femoroacetabular impingement imaging-part 1: overview. Eur Radiol. 2020;30(10):5281-5297. Epub 2020 Jul 17. Erratum in: Eur Radiol. 2020 Dec;30(12):6966-6967. PMID: 32405754.
Mascarenhas VV, et al. The Lisbon Agreement on femoroacetabular impingement imaging-part 2: general issues, parameters, and reporting. Eur Radiol. 2021;31: 4634-4651. Epub 2021 Jan 7. PMID: 33411052.
The Royal College of Radiologists. RCR IRefer Guidelines: Making the Best Use of Clinical Radiology. London: The Royal College of Radiologists, [Internet]. 2017 [cited 2017].
Reiman MP, et al. Consensus recommendations on the classification, definition and diagnostic criteria of hip-related pain in young and middle-aged active adults from the International Hip-related Pain Research Network, Zurich 2018. Br J Sports Med. 2020 Jun;54(11):631-641. Epub 2020 Jan 20. PMID: 31959678.
-
For patients with hip or knee pain likely related to degenerative joint pathology, if x-ray demonstrates greater than mild osteoarthritis, MRI may not be indicated as it often will not advance diagnosis or management. Musculoskeletal specialist consultation should be considered, to determine if MRI is required.
Sources:
Fox MG, et al. ACR appropriateness criteria® chronic knee pain. J Am Coll Radiol. 2018;15(11S): S302-S312. PMID: 30392599.
Gorelik N, et al. Optimizing Musculoskeletal Imaging Referrals: Making Wise Choices a Knee-Jerk Reaction. Can Assoc Radiol J. 2025 May 26:8465371251339389. Epub ahead of print. PMID: 40420549.
Hamel C, et al. Canadian Association of Radiologists Musculoskeletal System Diagnostic Imaging Referral Guideline. Can Assoc Radiol J. 2024; 75(2):269-278. Epub 2023 Sep 27. PMID: 37635274.
The Royal College of Radiologists. RCR IRefer Guidelines: Making the Best Use of Clinical Radiology. London: The Royal College of Radiologists. [Internet]. 2025. [cited 2025].
-
Not all pulmonary nodules require CT surveillance. Benign nodules are common and often represent sequelae of a prior healed infectious or inflammatory process, benign endobronchial mucus plugs or pulmonary lymph nodes. Specifically, nodules with a benign pattern of calcification do not require any surveillance and should be clearly described as benign in the radiology report. These include nodules that are completely calcified, small nodules with central calcification and nodules with a complete circumferential ring of calcification. Calcification may be difficult to identify without thin section (less than 2 mm) slice reformats. Incidental nodules meeting criteria for a perifissural nodule typical for a intrapulmonary lymph node do not require surveillance. Perifissural lymph nodes have a characteristic CT appearance: located along a fissure, smoothly marginated, homogenously solid, polygonal, triangular or ovoid shaped and measuring less than 10mm. Regardless of CT appearance an incidental solid nodule that has been stable for 2 years can also be safely considered benign (note that many nodules only require one year of surveillance). By making it clear that a nodule does not meet criteria for surveillance, radiologists may reduce unnecessary CT. Radiologists may wish to describe some benign nodules as post inflammatory, rather than “non-specific” to help reduce anxiety and limit over investigation. Referencing relevant practice guidelines can provide added confidence and can add support to the radiologist’s recommendation.
Joint recommendation with the Canadian Thoracic Society
Sources:
Callister MEJ, et al. British Thoracic Society Pulmonary Nodule Guideline Development Group; British Thoracic Society Standards of Care Committee. British Thoracic Society guidelines for the investigation and management of pulmonary nodules. 2015 Aug;70 Suppl 2:ii1-ii54. Erratum in: Thorax. 2015 Dec;70(12):1188. PMID: 26082159.
Christensen J, et al. ACR Lung-RADS v2022: Assessment Categories and Management Recommendations. Chest. 2024 Mar;21(3):473-488. PMID: 37820837.
MacMahon H, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology. 2017 Jul;284(1):228-243. Epub 2017 Feb 23. PMID: 28240562.
McWilliams A, et al. Probability of cancer in pulmonary nodules detected on first screening CT. N Engl J Med. 2013 Sep 5;369(10):910-9. PMID: 24004118.
Mets OM, et al. Incidental perifissural nodules on routine chest computed tomography: lung cancer or not? Eur Radiol. 2018;28(3):1095-1101. PMID: 28986629.
Schreuder A, et al. Typical CT Features of Intrapulmonary Lymph Nodes: A Review. Radiol Cardiothorac Imaging. 2020;2(4):e190159. PMID: 33778597.
-
Incidental pulmonary nodules are commonly detected on chest CT, and extensive evidence demonstrates that the majority of solid nodules have a low probability of malignancy. Multiple validated clinical and Bayesian prediction models confirm that malignancy risk varies widely based on nodule characteristics and patient factors, making uniform follow-up inappropriate and potentially harmful. When radiology reports identify incidental nodules without providing explicit follow-up recommendations, including clear statements when no surveillance is indicated, clinical management becomes variable, leading to unnecessary repeat imaging, increased healthcare costs, cumulative radiation exposure, and patient anxiety. This variability is further amplified by known inter-observer differences in nodule detection and classification, underscoring the importance of standardized guidance within reports to ensure consistent downstream care. International guidelines from the Fleischner Society and British Thoracic Society, as well as recent Canadian expert consensus recommendations, emphasize risk-stratified management and clearly define scenarios in which routine follow-up is not required. Including clear, guideline-based follow-up recommendations within CT reports, particularly explicit statements indicating when no further imaging is necessary, improves communication between radiologists and referring clinicians, reduces practice variability, supports appropriate risk-based decision-making, and minimizes low-value imaging while ensuring timely and appropriate surveillance for nodules with clinically meaningful malignancy risk.
Sources:
Callister MEJ, et al. British Thoracic Society Pulmonary Nodule Guideline Development Group; British Thoracic Society Standards of Care Committee. British Thoracic Society guidelines for the investigation and management of pulmonary nodules. Thorax. 2015 Aug;70 Suppl 2:ii1-ii54. Erratum in: Thorax. 2015 Dec;70(12):1188. PMID: 26082159.
Digby GC, et al. Recommendations to Improve Management of Incidental Pulmonary Nodules in Canada: Expert Panel Consensus. Can Assoc Radiol J. 2024;75(4):895-906. PMID: 38869196.
Gould MK, et al. Veterans Affairs SNAP Cooperative Study Group A clinical model to estimate the pretest probability of lung cancer in patients with solitary pulmonary nodules. Chest. 2007 Feb;131(2):383-8. PMID: 17296637.
MacMahon H, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology. 2017 Jul;284(1):228-243. Epub 2017 Feb 23. PMID: 28240562.
van Riel SJ, et al. Observer variability for classification of pulmonary nodules on low-dose CT images and its effect on nodule management. Radiology. 2015 Dec;277(3):863-71. Epub 2015 May 22. PMID: 26020438.
-
Current evidence regarding malignant risk of lung nodules by size is based on either 2-dimensional mean measurements or volume measurements. Mean dimension can be calculated by the average of the longest dimension and the perpendicular short axis dimension on a single CT plane. This is best measured in whichever plane produces the largest mean dimension value. Measurements should be made with thin section reconstruction (maximum thickness 1.5 mm). If radiologists report only the longest diameter, malignant risk will be overestimated, particularly for irregular (non-spherical) nodules. Using longest dimension to guide recommendations may result in unnecessary surveillance, over surveillance and over investigation. Guidelines from the Fleischner society regarding incidental pulmonary nodules use mean, not longest, dimension. ACR LungRADS® guidelines regarding management of screen-detected nodules also use mean dimension.
Joint recommendation with the Canadian Thoracic Society
Sources:
Creamer AW, et al. Performance of volume and diameter thresholds in malignancy prediction of solid nodules in lung cancer screening. Thorax. 2025 Aug 15;80(9):624-631. PMID: 40456600.
de Koning HJ, et al. Reduced Lung-Cancer Mortality with Volume CT Screening in a Randomized Trial. Engl J Med. 2020 Feb 6;382(6):503-513. Epub 2020 Jan 29. PMID: 31995683.
MacMahon H, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology. 2017 Jul;284(1):228-243. Epub 2017 Feb 23. PMID: 28240562.
McWilliams A, et al. Probability of cancer in pulmonary nodules detected on first screening CT. N Engl J Med. 2013 Sep 5;369(10):910-9. PMID: 24004118.
-
Accurate assessment of nodule growth requires reviewing all available prior imaging, and not just the most recent prior scan. Guideline frameworks emphasize longitudinal comparison over an extended interval often up to two years for solid nodules, 5 years for subsolid nodules, because stability over a longer period of time favours benignity. Volume doubling times for solid cancers are in the range of 100-400 days whereas mean doubling times for subsolid nodules are 3-5 years. The Fleischner Society’s 2017 Guidelines underscores serial assessment to accurately determine if a nodule is increasing in size. This is of critical importance for subsolid nodules that are typically indolent and slow-growing. For subsolid nodules, it is often necessary to compare to the oldest prior CT scan or baseline CT scan that is available to appreciate the slow growth in size and/or density. Restricting comparison to only the most recent CT scan increases the risk of misclassifying a nodule as stable when in fact it is slowly increasing in size when compared to remote CT scans or the baseline CT scan.
Joint recommendation with the Canadian Thoracic Society
Sources:
Hasegawa M, et al. Growth rate of small lung cancers detected on mass CT screening. Br J Radiol. 2000 Dec;73(876):1252-9. PMID: 11205667.
MacMahon H, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology. 2017 Jul;284(1):228-243. Epub 2017 Feb 23. PMID: 28240562.
Yankelevitz DF, et al. CT screening for lung cancer: nonsolid nodules in baseline and annual repeat rounds. Radiology. 2015 Nov;277(2):555-64. Epub 2015 Jun 23. PMID: 26101879.
-
Recommendations 1 – 5
The Canadian Association of Radiologists (CAR) established its Choosing Wisely Canada Top 5 recommendations by initially soliciting expert opinion from physician leaders within its Board of Directors. A working group was then formed to further identify common clinical scenarios in which imaging may be misused and should be reconsidered. The working group included CAR leaders in the areas of medical imaging appropriateness and access. The list was narrowed down based on the highest potential for improvement, representing a broad range of tests and the availability of strong guidelines. The first three recommendations had previously been researched, submitted and adopted for another appropriateness initiative underway in Canada in 2013. That process included obtaining stakeholder support from a range of colleagues including technologists, sonographers, nuclear medicine physicians, family physicians and physicists. Two additional recommendations were added using similar criteria, including a comprehensive literature search undertaken through the Canadian Agency for Drugs and Technologies in Health. The full list of proposed recommendations was then vetted by stakeholder organizations, such as provincial radiology organizations and the full CAR membership. Item 4 was adapted with permission from the Five Things Physicians and Patients Should Question, © 2012 American College of Radiology.
Recommendations 6 – 8
A Steering Committee comprising multidisciplinary MSK experts was convened to guide recommendation development. Using a two-round Delphi method, committee members selected the top 3 scenarios from the CAR MSK referral guidelines deemed most impactful for addressing overuse. Recommendations based on these scenarios were then drafted using the CWC format.
Sources:
American College of Radiology. ACR appropriateness criteria® low back pain. [Internet]. 2015 [cited 2017 May 5].
Bach SM, et al. Guideline update: What’s the best approach to acute low back pain? J Fam Pract. 2009 Dec;58(12):E1. PMID: 19961812.
Choosing Wisely. American Academy of Family Physicians (AAFP): Fifteen things physicians and patients should question [Internet]. 2012 [cited 12 mars 2014].
Chou R, et al. Imaging strategies for low-back pain: Systematic review and meta-analysis. Lancet. 2009 Feb 7;373(9662):463-72. PMID: 19200918.
Chou R, et al. Diagnostic imaging for low back pain: Advice for high-value health care from the American College of Physicians. Ann Intern Med. 2011 Feb 1;154(3):181-9. PMID: 21282698.
Goertz M, et al. Adult acute and subacute low back pain [Internet]. 2012 Nov [cited 2017 May 5].
Michigan Quality Improvement Consortium. Management of acute low back pain [Internet]. 2012 Sep [cited 2014 Feb 23].
National Collaborating Centre for Primary Care (UK). Low back pain: Early management of persistent non-specific low back pain. 2009 May. PMID: 20704057.
Toward Optimized Practice. Guideline for the evidence-informed primary care management of low back pain [Internet]. 2011 Nov [cited 2017 May 5].
University of Michigan Health System. Acute low back pain [Internet]. 2010 Jan [cited 2017 May 5].
van Rijn RM, et al. Computed tomography for the diagnosis of lumbar spinal pathology in adult patients with low back pain or sciatica: A diagnostic systematic review. Eur Spine J. 2012 Feb;21(2):228-39. PMID: 21915747.
Wassenaar M, et al. Magnetic resonance imaging for diagnosing lumbar spinal pathology in adult patients with low back pain or sciatica: A diagnostic systematic review. Eur Spine J. 2012 Feb;21(2):220-7. PMID: 21922287.
Davis PC, et al. ACR appropriateness criteria® head trauma [Internet]. 2015 [cited 2017 May 5].
Holmes MW, et al. The cost-effectiveness of diagnostic management strategies for adults with minor head injury. Injury. 2012 Sep;43(9):1423-31. PMID: 21835403.
Jagoda AS, et al. Clinical policy: Neuroimaging and decisionmaking in adult mild traumatic brain injury in the acute setting. Ann Emerg Med. 2008 Dec;52(6):714-48. PMID: 19027497.
Management of Concussion/mTBI Working Group. VA/DoD clinical practice guideline for management of concussion/mild traumatic brain injury (mTBI)]. J Rehabil Res Dev. 2009;46(6):CP1-68. PMID: 20108447.
Marshall S, et al. Clinical practice guidelines for mild traumatic brain injury and persistent symptoms. Can Fam Physician. 2012 Mar;58(3):257,67, e128-40. PMID: 22518895.
Motor Accidents Authority NSW (MAA). Guidelines for mild traumatic brain injury following closed head injury: Acute/post-acute assessment and management [Internet]. 2008 [cited 2017 May 5].
Ontario Neurotrauma Foundation. Guidelines for mild traumatic brain injury and persistent symptoms [Internet]. 2011 [cited 2017 May 5].
Pandor A, et al. Diagnostic management strategies for adults and children with minor head injury: A systematic review and an economic evaluation. Health Technol Assess. 2011 Aug;15(27):1-202. PMID: 21806873.
Pandor A, et al. Diagnostic accuracy of clinical characteristics for identifying CT abnormality after minor brain injury: A systematic review and meta-analysis. J Neurotrauma. 2012 Mar 20;29(5):707-18. PMID: 21806474.
Reed D. Adult trauma clinical practice guidelines: Initial management of closed head injury in adults [Internet]. 2011 Nov [cited 2017 May 5].
Scottish Intercollegiate Guidelines Network (SIGN). Early management of patients with a head injury: A national clinical guideline [Internet]. 2009 May [cited 2017 May 5].
Smits M, et al. Minor head injury: CT-based strategies for management–a cost-effectiveness analysis. Radiology. 2010 Feb;254(2):532-40. PMID: 20093524.
West TA, et al. Care of the patient with mild traumatic brain injury [Internet]. 2011 [cited 2017 May 5].
Work Loss Data Institute. Head (trauma, headaches, etc., not including stress & mental disorders) [Internet]. 2011 [cited 2017 May 5].
Beithon J, et al. Institute for clinical systems improvement. Diagnosis and treatment of headache [Internet]. 2013 Jan [cited 2017 May 5].
Choosing Wisely. American College of Radiology: Five things physicians and patients should question [Internet]. 2012 Apr 4 [cited 2017 May 5].
Edlow JA, et al. Clinical policy: Critical issues in the evaluation and management of adult patients presenting to the emergency department with acute headache. Ann Emerg Med. 2008 Oct;52(4):407-36. PMID: 18809105.
Hayes LL, et al. ACR appropriateness criteria®: Headache – child [Internet]. 2012 [cited 2014 Feb 23].
Health Quality Ontario. Neuroimaging for the evaluation of chronic headaches: An evidence-based analysis. Ont Health Technol Assess Ser. 2010;10(26):1-57. PMID: 23074404.
Jordan YJ, et al. Computed tomography imaging in the management of headache in the emergency department: Cost efficacy and policy implications. J Natl Med Assoc. 2009 Apr;101(4):331-5. PMID: 19397223.
National Institute for Health and Clinical Excellence (NICE). Headaches: Diagnosis and management of headaches in young people and adults [Internet]. 2012 Sep [2017 May 5].
Sandrini G, et al. Neurophysiological tests and neuroimaging procedures in non-acute headache (2nd edition). Eur J Neurol. 2011 Mar;18(3):373-81. PMID: 20868464.
Scottish Intercollegiate Guidelines Network (SIGN). Diagnosis and management of headache in adults: A national clinical guideline [Internet]. 2008 Nov [2017 May 5].
Toward Optimized Practice. Guideline for primary care management of headache in adults [Internet]. 2016 Sep [2017 May 5].
Adibe OO, et al. An evidence-based clinical protocol for diagnosis of acute appendicitis decreased the use of computed tomography in children. J Pediatr Surg. 2011 Jan;46(1):192-6. PMID: 21238665.
Bachur RG, et al. The effect of abdominal pain duration on the accuracy of diagnostic imaging for pediatric appendicitis. Ann Emerg Med. 2012 Nov;60(5):582,590.e3. PMID: 22841176.
Bachur RG, et al. Diagnostic imaging and negative appendectomy rates in children: Effects of age and gender. Pediatrics. 2012 May;129(5):877-84. PMID: 22508920.
Bachur RG, et al. Advanced radiologic imaging for pediatric appendicitis, 2005-2009: Trends and outcomes. J Pediatr. 2012 Jun;160(6):1034-8. PMID: 22192815.
Burr A, et al. Glowing in the dark: Time of day as a determinant of radiographic imaging in the evaluation of abdominal pain in children. J Pediatr Surg. 2011 Jan;46(1):188-91. PMID: 21238664.
Choosing Wisely. American College of Radiology: Five things physicians and patients should question [Internet]. 2013 [cited 2014 Mar 12].
Krishnamoorthi R, et al. Effectiveness of a staged US and CT protocol for the diagnosis of pediatric appendicitis: Reducing radiation exposure in the age of ALARA. Radiology. 2011 Apr;259(1):231-9. PMID: 21324843.
Park JS, et al. Accuracies of diagnostic methods for acute appendicitis. Am Surg. 2013 Jan;79(1):101-6. PMID: 23317620.
Ramarajan N, et al. An interdisciplinary initiative to reduce radiation exposure: Evaluation of appendicitis in a pediatric emergency department with clinical assessment supported by a staged ultrasound and computed tomography pathway. Acad Emerg Med. 2009 Nov;16(11):1258-65. PMID: 20053244.
Santillanes G, et al. Prospective evaluation of a clinical practice guideline for diagnosis of appendicitis in children. Acad Emerg Med. 2012 Aug;19(8):886-93. PMID: 22849662.
Thirumoorthi AS, et al. Managing radiation exposure in children–reexamining the role of ultrasound in the diagnosis of appendicitis. J Pediatr Surg. 2012 Dec;47(12):2268-72. PMID: 23217887.
Wan MJ, et al. Acute appendicitis in young children: Cost-effectiveness of US versus CT in diagnosis–a Markov decision analytic model. Radiology. 2009 Feb;250(2):378-86. PMID: 19098225.
Bennett DL, et al. ACR appropriateness criteria® acute trauma to the foot [Internet]. 2014 [cited 2017 May 5].
Blackham JE, et al. Can patients apply the ottawa ankle rules to themselves? Emerg Med J. 2008 Nov;25(11):750-1. PMID: 18955612.
Can U, et al. Safety and efficiency of the Ottawa ankle rule in a Swiss population with ankle sprains. Swiss Med Wkly. 2008 May 3;138(19-20):292-6. PMID: 18491243.
Dowling S, et al. Accuracy of Ottawa Ankle Rules to exclude fractures of the ankle and midfoot in children: a meta-analysis. Acad Emerg Med. 2009 Apr;16(4):277-87. PMID: 19187397.
Gravel J, et al. Prospective validation and head-to-head comparison of 3 ankle rules in a pediatric population. Ann Emerg Med. 2009 Oct;54(4):534,540.e1. PMID: 19647341.
Jenkin M, et al. Clinical usefulness of the Ottawa ankle rules for detecting fractures of the ankle and midfoot. J Athl Train. 2010 Sep-Oct;45(5):480-2. PMID: 20831394.
Knudsen R, et al. Validation of the Ottawa ankle rules in a Danish emergency department. Dan Med Bull. 2010 May;57(5):A4142. PMID: 20441713.
Lin CW, et al. Economic evaluations of diagnostic tests, treatment and prevention for lateral ankle sprains: A systematic review. Br J Sports Med. 2013 Dec;47(18):1144-9. PMID: 22554849.
National Guideline Clearinghouse. Guideline summary: Ankle and foot disorders [Internet]. 28 Oct 2013 [cited 5 May 2017].
Petscavage J, et al. Overuse of concomitant foot radiographic series in patients sustaining minor ankle injuries. Emerg Radiol. 2010 Jul;17(4):261-5. PMID: 19834751.
Polzer H, et al. Diagnosis and treatment of acute ankle injuries: Development of an evidence-based algorithm. Orthop Rev (Pavia). 2012 Jan 2;4(1):e5. PMID: 22577506.
Seah R, et al. Managing ankle sprains in primary care: What is best practice? A systematic review of the last 10 years of evidence. Br Med Bull. 2011;97:105-35. PMID: 20710025.
Wang X, et al. Clinical value of the Ottawa ankle rules for diagnosis of fractures in acute ankle injuries. PLoS One. 2013 Apr 30;8(4):e63228. PMID: 23646202.
Work Loss Data Institute. Guideline summary: Ankle & foot (acute & chronic). [Internet]. 2013 Oct 28 [cited May 5, 2017]
Gorelik N, et al. Optimizing Musculoskeletal Imaging Referrals: Making Wise Choices a Knee-Jerk Reaction. Can Assoc Radiol J. 2025 May 26:8465371251339389. Epub ahead of print. PMID: 40420549.
Hamel C, et al. Canadian Association of Radiologists Musculoskeletal System Diagnostic Imaging Referral Guideline. Can Assoc Radiol J. 2024; 75(2):269-278. Epub 2023 Sep 27. PMID: 37635274.
Small KM, et al. ACR appropriateness criteria® shoulder pain-atraumatic. J Am Coll Radiol. 2018; 15(11S):S388-S402. PMID: 30392607.
Sconfienza LM, et al. Clinical indications for musculoskeletal ultrasound updated in 2017 by European Society of Musculoskeletal Radiology (ESSR) consensus. Eu Radiol. 2018;28(12):5338-5351. Epub 2018 Jun 6. PMID: 29876703.
The Royal College of Radiologists. RCR IRefer Guidelines: Making the Best Use of Clinical Radiology. London: The Royal College of Radiologists, [Internet]. 2017 [cited 2017].
Weber S, et al. Management of rotator cuff injuries. J Am Acad Orthop Surg. 2020;28(5):e193-e201. PMID: 31599763.
Gorelik N, et al. Optimizing Musculoskeletal Imaging Referrals: Making Wise Choices a Knee-Jerk Reaction. Can Assoc Radiol J. 2025 May 26:8465371251339389. Epub ahead of print. PMID: 40420549.
Hamel C, et al. Canadian Association of Radiologists Musculoskeletal System Diagnostic Imaging Referral Guideline. Can Assoc Radiol J. 2024; 75(2):269-278. Epub 2023 Sep 27. PMID: 37635274.
Jawetz ST, et al. ACR Appropriateness Criteria® Chronic Hip Pain: 2022 Update. J Am Coll Radiol. 2023; 20(5): S33-S48. PMID: 37236751.
Mascarenhas VV, et al. The Lisbon Agreement on femoroacetabular impingement imaging-part 1: overview. Eur Radiol. 2020;30(10):5281-5297. Epub 2020 Jul 17. Erratum in: Eur Radiol. 2020 Dec;30(12):6966-6967. PMID: 32405754.
Mascarenhas VV, et al. The Lisbon Agreement on femoroacetabular impingement imaging-part 2: general issues, parameters, and reporting. Eur Radiol. 2021;31: 4634-4651. Epub 2021 Jan 7. PMID: 33411052.
The Royal College of Radiologists. RCR IRefer Guidelines: Making the Best Use of Clinical Radiology. London: The Royal College of Radiologists, [Internet]. 2017 [cited 2017].
Reiman MP, et al. Consensus recommendations on the classification, definition and diagnostic criteria of hip-related pain in young and middle-aged active adults from the International Hip-related Pain Research Network, Zurich 2018. Br J Sports Med. 2020 Jun;54(11):631-641. Epub 2020 Jan 20. PMID: 31959678.
Fox MG, et al. ACR appropriateness criteria® chronic knee pain. J Am Coll Radiol. 2018;15(11S): S302-S312. PMID: 30392599.
Gorelik N, et al. Optimizing Musculoskeletal Imaging Referrals: Making Wise Choices a Knee-Jerk Reaction. Can Assoc Radiol J. 2025 May 26:8465371251339389. Epub ahead of print. PMID: 40420549.
Hamel C, et al. Canadian Association of Radiologists Musculoskeletal System Diagnostic Imaging Referral Guideline. Can Assoc Radiol J. 2024; 75(2):269-278. Epub 2023 Sep 27. PMID: 37635274.
The Royal College of Radiologists. RCR IRefer Guidelines: Making the Best Use of Clinical Radiology. London: The Royal College of Radiologists. [Internet]. 2025. [cited 2025].
Callister MEJ, et al. British Thoracic Society Pulmonary Nodule Guideline Development Group; British Thoracic Society Standards of Care Committee. British Thoracic Society guidelines for the investigation and management of pulmonary nodules. 2015 Aug;70 Suppl 2:ii1-ii54. Erratum in: Thorax. 2015 Dec;70(12):1188. PMID: 26082159.
Christensen J, et al. ACR Lung-RADS v2022: Assessment Categories and Management Recommendations. Chest. 2024 Mar;21(3):473-488. PMID: 37820837.
MacMahon H, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology. 2017 Jul;284(1):228-243. Epub 2017 Feb 23. PMID: 28240562.
McWilliams A, et al. Probability of cancer in pulmonary nodules detected on first screening CT. N Engl J Med. 2013 Sep 5;369(10):910-9. PMID: 24004118.
Mets OM, et al. Incidental perifissural nodules on routine chest computed tomography: lung cancer or not? Eur Radiol. 2018;28(3):1095-1101. PMID: 28986629.
Schreuder A, et al. Typical CT Features of Intrapulmonary Lymph Nodes: A Review. Radiol Cardiothorac Imaging. 2020;2(4):e190159. PMID: 33778597.
Callister MEJ, et al. British Thoracic Society Pulmonary Nodule Guideline Development Group; British Thoracic Society Standards of Care Committee. British Thoracic Society guidelines for the investigation and management of pulmonary nodules. Thorax. 2015 Aug;70 Suppl 2:ii1-ii54. Erratum in: Thorax. 2015 Dec;70(12):1188. PMID: 26082159.
Digby GC, et al. Recommendations to Improve Management of Incidental Pulmonary Nodules in Canada: Expert Panel Consensus. Can Assoc Radiol J. 2024;75(4):895-906. PMID: 38869196.
Gould MK, et al. Veterans Affairs SNAP Cooperative Study Group A clinical model to estimate the pretest probability of lung cancer in patients with solitary pulmonary nodules. Chest. 2007 Feb;131(2):383-8. PMID: 17296637.
MacMahon H, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology. 2017 Jul;284(1):228-243. Epub 2017 Feb 23. PMID: 28240562.
van Riel SJ, et al. Observer variability for classification of pulmonary nodules on low-dose CT images and its effect on nodule management. Radiology. 2015 Dec;277(3):863-71. Epub 2015 May 22. PMID: 26020438.
Creamer AW, et al. Performance of volume and diameter thresholds in malignancy prediction of solid nodules in lung cancer screening. Thorax. 2025 Aug 15;80(9):624-631. PMID: 40456600.
de Koning HJ, et al. Reduced Lung-Cancer Mortality with Volume CT Screening in a Randomized Trial. Engl J Med. 2020 Feb 6;382(6):503-513. Epub 2020 Jan 29. PMID: 31995683.
MacMahon H, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology. 2017 Jul;284(1):228-243. Epub 2017 Feb 23. PMID: 28240562.
McWilliams A, et al. Probability of cancer in pulmonary nodules detected on first screening CT. N Engl J Med. 2013 Sep 5;369(10):910-9. PMID: 24004118.
Hasegawa M, et al. Growth rate of small lung cancers detected on mass CT screening. Br J Radiol. 2000 Dec;73(876):1252-9. PMID: 11205667.
MacMahon H, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology. 2017 Jul;284(1):228-243. Epub 2017 Feb 23. PMID: 28240562.
Yankelevitz DF, et al. CT screening for lung cancer: nonsolid nodules in baseline and annual repeat rounds. Radiology. 2015 Nov;277(2):555-64. Epub 2015 Jun 23. PMID: 26101879.
About Choosing Wisely Canada
Choosing Wisely Canada is the national voice for reducing unnecessary tests and treatments in health care. One of its important functions is to help clinicians and patients engage in conversations that lead to smart and effective care choices.
Web: choosingwiselycanada.org
Email: info@choosingwiselycanada.org
Twitter: @ChooseWiselyCA
Facebook: /ChoosingWiselyCanada
Lower Back Pain Imaging
Don't image for lower back pain unless red flags are present.
Common Tests, Treatments, and Procedures You May Think You Need
Let’s think again.
CT Scans for Adults with Head Injuries
When you need one and when you don’t.
CT Scans for Children with Head Injuries
When they need them—and when they don’t
Imaging Tests for Headaches
When you need them and when you don’t.
Imaging Tests for Lower Back Pain
When you need them and when you don’t.