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The Royal Australian and New Zealand College of Radiologists – Faculty of Clinical Radiology

RANZCR is a non-profit association that delivers skills, knowledge, and insight to promote the science and practice of the medical specialties of clinical radiology (diagnostic and interventional) and radiation oncology.

Recommendations and resources

1) Don’t request imaging for acute ankle trauma unless indicated by the Ottawa Ankle Rules (localised bone tenderness or inability to weight-bear as defined in the Rules).

Most clinically significant acute ankle injuries can be diagnosed with history, examination, and selective use of plain radiography.

Extensive validation studies have shown that the Ottawa Ankle Rules can be safely applied to adult and paediatric populations.

Selective use of plain radiography in patients with acute ankle injury is useful in identifying patients who have sustained clinically important fracture, dislocation, and osteochondral injuries. However, acute ligamentous injuries involving the anterior talofibular ligament can be diagnosed clinically and treated symptomatically.
When there are persistent symptoms (such as pain and swelling) after an acute injury, which raise suspicion of either instability or other internal derangement, such as osteochondral injury, MRI can be used if the non-urgent (or delayed or elective or similar) weight bearing x-rays show no abnormality.

Recommendation released April 2015, reviewed April 2016.

Resources

2) Don’t request duplex compression ultrasound for suspected lower limb deep venous thrombosis in ambulatory outpatients unless the Wells Score (deep venous thrombosis risk assessment score) is greater than 2, OR if less than 2, D dimer assay is positive.

The potential complications of untreated deep venous thrombosis (DVT) include thrombus propagation, pulmonary embolism (PE) and death from PE. A significant but under-appreciated longer-term complication is post-thrombotic syndrome (PTS) and this can occur in up to 40% of patients with proximal DVT, as a result of venous incompetence and hypertension.

Wells et al. (2003) showed that ambulatory outpatients with suspected lower limb DVT and a DVT risk assessment score (Wells Score) of less than 2, can have DVT excluded by a negative result on D dimer assay, obviating the need to perform duplex compression ultrasound. The lower limit of the negative predictive value of the combination of a score.

Recommendation released April 2015, reviewed April 2016.

Resources

3) Don’t request any diagnostic testing for suspected pulmonary embolism (PE) unless indicated by Wells Score (or Charlotte Rule) followed by PE Rule-out Criteria (in patients not pregnant). Low risk patients in whom diagnostic testing is indicated should have PE excluded by a negative D dimer, not imaging.

Pulmonary embolism (PE) affects 2-3 per 1000 adults per year. It can be fatal if untreated, more often in hospitalised people than outpatients. The symptoms and signs of PE (chest pain, cough, dyspnoea, and tachycardia) are non specific and so imaging is required to make the diagnosis.

PE is diagnosed by direct (CT pulmonary angiogram) or indirect (ventilation/perfusion or “V/Q” lung scanning) demonstration of the emboli within the pulmonary arterial tree. PE can be excluded in low risk patients by a negative result on whole blood D dimer. Some low risk patients (“Pulmonary Embolism Rule-out Criteria [PERC] negative”) are at such low risk they require no diagnostic testing, including D dimer.
Clinical decision rules (CDRs) are more specific than clinical gestalt in determining which patients are unlikely to have PE, and thus can prevent unnecessary imaging in these groups.

Validated risk assessment strategies are not applicable to pregnant women and D dimer is physiologically elevated early in pregnancy. Ventilation perfusion lung scanning is the test of choice in the presence of a normal chest radiograph in a pregnant woman with suspected PE as the radiation dose to the breast is much lower than for CT pulmonary angiography and the fetal dose is very small and comparable for both imaging tests.

Recommendation released April 2015, reviewed April 2016.

Resources

4) Don’t perform imaging for patients with non-specific acute low back pain and no indicators of a serious cause for low back pain.

Low back pain (LBP) is extremely common, being the third most common health complaint seen by Australian general practitioners.
A simple classification places patients into one of three categories:

  • LBP associated with sciatica or spinal canal stenosis
  • Serious spinal pathology (such as cancer, infection, fracture, and cauda equina syndrome) comprises 1% of GP presentations with LBP
  • Non-specific low back pain (90% of presentations)

When evaluating patients with acute LBP, one of the key issues to be addressed is whether or not the patient should be investigated using imaging to confirm or refute the presence of an underlying/associated condition that would change the subsequent medical treatment or investigation of the patient.
Age over 70 years, trauma, corticosteroid therapy, and female gender are risk factors for fracture and previous or current cancer significantly increases the likelihood of cancer related back pain. At least one of fever, systemic symptoms, recent invasive procedure or sepsis, or elevated CRP are seen in most but not all patients with discitis or epidural abscess. New lower limb or bladder motor dysfunction increase the likelihood of cauda equina syndrome in a patient with LBP and are indications for emergency MRI.

Recommendation released April 2015, reviewed April 2016.

Resources

5) Don’t request imaging of the cervical spine in trauma patients, unless indicated by a validated clinical decision rule.

Cervical spine imaging of every trauma patient is costly and results in significant radiation exposure to a large number of patients, very few of whom will have a spinal column injury. Clinical decision rules have been developed that identify patients who can safely be managed without imaging. These rules include the Canadian C-Spine rule or Nexus Low Risk Criteria. The Canadian C-Spine Rule provides higher specificity and lower imaging requirements, and should be used if possible.

This is a joint recommendation with The Australasian College for Emergency Medicine (ACEM).

Recommendation released April 2015, reviewed April 2016.

Resources

6) Don’t request computed tomography (CT) head scans in patients with a head injury, unless indicated by a validated clinical decision rule.

Most head injuries presenting to emergency departments will be minor and do not require immediate neurosurgical intervention or inpatient care. Mild head injury patients can be risk stratified into ‘low’ or ‘high’ risk groups based on the presence or absence of identified clinical risk factors. Current validated clinical decision rules include the Canadian CT Head Rule (for adults) or the PECARN (Paediatric Emergency Care Applied Research Network) Tool (for children). These rules can safely identify patients who can be discharged home, without CT scanning.

This is a joint recommendation with Australasian College for Emergency Medicine (ACEM).

Recommendation released April 2015, reviewed April 2016.

Resources

Supporting evidence