Synopsis
Select musculoskeletal imaging by the clinical question, understand what radiography, ultrasound and MRI can and cannot establish, and integrate findings without delaying urgent aspiration, referral or treatment.
- Begin with a question such as fracture, structural damage, active synovitis, tendon tear, sacroiliitis or spinal compression; 'pain' alone is not an imaging indication.
- Plain radiography shows alignment, fracture, osteophytes, joint-space loss, erosions, periosteal change and mineralisation but is relatively insensitive to early soft-tissue inflammation.
- Ultrasound provides dynamic assessment of accessible synovium, effusions, tendons, entheses and Doppler vascularity and can guide aspiration or injection.
Key red flags
Cord, cauda equina or rapidly progressive focal neurological features require emergency MRI through the acute pathway, not routine rheumatology booking.
Investigation priorities
Assess fracture, alignment, structural arthropathy, calcification and established inflammatory damage.
Management branches
Possible infection, unstable fracture, compartment syndrome or neurological compression.
- Stabilise the patient and perform focused neurovascular examination, obtaining the fastest appropriate radiograph, ultrasound or MRI through the emergency pathway.
- Use ultrasound for urgent aspiration when helpful, but take cultures and begin indicated antimicrobial or surgical treatment without waiting for elective cross-sectional imaging.