What imaging is recommended for olecranon (elbow) bursitis?

Imaging for Olecranon Bursitis

Plain radiographs are the recommended initial imaging modality for olecranon bursitis to exclude fractures, dislocations, or bony abnormalities. 1

Initial Imaging Approach

Start with plain radiographs of the elbow as the first-line imaging study. 1 This recommendation comes from the American College of Radiology and serves to:

• Rule out fractures or dislocations that may mimic or coexist with bursitis 2
• Identify olecranon spurs (present in approximately 21% of cases), which correspond to the triceps tendon insertion 3
• Detect amorphous calcium deposits within the bursa 3
• Visualize heterotopic ossification or soft tissue calcifications 2

The ACR guidelines for acute and chronic elbow pain consistently emphasize radiographs as the beneficial initial imaging assessment, though the provided guidelines focus primarily on intra-articular pathology rather than bursal disease specifically. 2

Advanced Imaging When Clinically Indicated

Ultrasound

Ultrasound is the preferred advanced imaging modality for olecranon bursitis when further characterization is needed beyond plain films. 1, 4

Ultrasound effectively demonstrates:

• Small fluid collections with high sensitivity, even in early manifestations 4
• Bursal thickening and heterogeneous echogenicity in chronic cases 1
• Synovial proliferation (detected in 15% of cases) 4
• Loose bodies within the bursa 4
• Increased blood flow patterns consistent with inflammation 4
• Concomitant triceps tendonitis with calcifications 4

The key advantage is that ultrasound allows real-time assessment and can guide aspiration procedures when needed. 4

MRI

MRI is not routinely necessary for olecranon bursitis but may be considered in complex or refractory cases. 5

Important limitations of MRI for bursitis:

• Septic and nonseptic olecranon bursitis show considerable overlap in MRI findings without statistically significant differences 5
• Features such as marginal lobulation (79% septic vs 48% nonseptic), bursa septation (64% vs 57%), and poorly defined margins (64% vs 67%) are not discriminatory 5
• The only reliable MRI finding: septic bursitis can be excluded in the absence of bursal and soft-tissue enhancement 5

MRI characteristics that may be seen (but are not diagnostic) include bursal fluid complexity, soft-tissue edema, elbow joint effusion, triceps edema or thickening, and bone marrow edema. 5

Clinical Decision Algorithm

1. All patients with suspected olecranon bursitis: Obtain plain radiographs 1

2. If diagnosis remains unclear or to assess bursal characteristics: Add ultrasound 1, 4

3. Reserve MRI for: Atypical presentations, suspected deep soft-tissue involvement, or when surgical planning requires detailed anatomic assessment 5

Common Pitfalls to Avoid

• Do not skip plain radiographs even when the diagnosis seems clinically obvious—bony abnormalities are present in a significant minority of cases and alter management 3

• Do not rely on MRI to differentiate septic from nonseptic bursitis—the imaging findings overlap extensively, and clinical assessment with bursal aspiration remains the gold standard 5

• Do not order CT, bone scan, or contrast-enhanced studies for routine olecranon bursitis—these modalities have no established role in bursal pathology and are not supported by ACR guidelines for this indication 2