X-Ray Appearance of Bursitis
Bursitis is typically not visible on plain radiographs, as x-rays have very limited sensitivity for detecting soft tissue inflammation and bursal fluid collections. 1
What X-Rays Can Show
Direct Signs (Usually Absent)
- Soft tissue swelling may be visible as the only radiographic finding in early bursitis, though this is nonspecific 1
- Calcifications within or around the bursa can be seen in chronic calcific bursitis (particularly trochanteric or subacromial bursitis), appearing as radio-opaque deposits adjacent to bony prominences 1
- Effacement of normal fat planes adjacent to the affected bursa may occasionally be detected 1
Indirect Signs
- Associated joint space narrowing or osteoarthritis may be present when bursitis is secondary to degenerative joint disease 1
- Bone erosions or proliferation can occur in chronic inflammatory bursitis (rheumatoid arthritis, gout) but these represent the underlying disease rather than the bursitis itself 1
- Soft tissue gas would only be visible in the rare case of septic bursitis with gas-forming organisms 1
Clinical Implications
Radiographs should still be obtained first to exclude other causes of pain such as fractures, tumors, or arthritis, but they are inadequate for diagnosing bursitis itself 1, 2
When X-Rays Are Normal or Noncontributory
Ultrasound is the preferred next imaging modality for suspected bursitis due to its superior ability to visualize bursal fluid, thickening, and inflammation 1, 2
- Ultrasound can reliably detect bursal collections, capsular and bursal thickening, and synovitis 2
- It allows dynamic assessment and can guide therapeutic injections in the same session 2
- It is cost-effective and highly accurate for superficial bursae (prepatellar, olecranon, trochanteric) 2, 3
MRI should be reserved for cases where ultrasound is equivocal, deeper structures need evaluation, or associated pathology (tendon tears, muscle involvement) is suspected 1, 2
Common Pitfall
The major pitfall is relying solely on radiographs to diagnose or exclude bursitis. Normal radiographs do not exclude bursitis and should prompt ultrasound evaluation when clinical suspicion remains high 1, 2. The exception is when calcific bursitis is present, which may be the only form reliably detected on x-ray 1.