Utility of imaging for rheumatological diseases
Imaging has a limited role in the diagnosis of rheumatological diseases and should only be performed if the:
- diagnosis cannot be confirmed on history and physical examination
- result of the imaging test will alter management or answer a clinical question.
Imaging often identifies abnormalities unrelated to the person’s symptoms and may cause them unnecessary harm (eg radiation exposure, overinvestigation, cost).
Imaging is important in the diagnosis or exclusion of:
- fractures—plain X-ray
- avascular necrosis (eg of the femoral head)—magnetic resonance imaging (MRI) scan
- specific soft-tissue knee injury following trauma in a young person (eg anterior cruciate ligament tear)—MRI scan
- septic discitis or osteomyelitis—MRI or computed tomography (CT) scan.
If a patient’s initial imaging is normal (eg X-ray for a knee injury) but their clinical examination is still suggestive of an injury or acute internal derangement, continue to investigate using more specialised imaging (eg MRI to identify ligament injury in the knee).
Imaging that does not add to a careful clinical assessment should be avoided; see Imaging to be avoided when investigating musculoskeletal symptoms in adults for a list of imaging to be avoided when investigating musculoskeletal symptoms in adults.
The following imaging is commonly requested, but does not add to careful clinical assessment and should be avoided:
- magnetic resonance imaging (MRI) scan for investigation of knee pain in the absence of trauma
- ultrasound for investigation of greater trochanteric pain syndrome
- ultrasound for investigation of nonspecific shoulder pain suggestive of subacromial pain syndrome
- imaging for investigation of nonspecific low back pain; for more information, see Assessment of spinal pain and imagingAustralian Rheumatology Association (ARA), 2018.