What is the recommended MRI protocol for diagnosing ischial bursitis and what are the treatment options?

MRI Protocol and Treatment for Ischial Bursitis

MRI is highly sensitive and specific for diagnosing ischial bursitis and should be performed after initial radiographs when ischial bursitis is suspected, with fluid-sensitive sequences being essential for proper evaluation. 1

Recommended MRI Protocol

Essential Sequences

• T1-weighted images
• Fluid-sensitive sequences (T2-weighted fat-saturated or STIR)
• Axial, coronal, and sagittal planes

Key MRI Findings

• Enlarged bursa deep to gluteus muscles and postero-inferior to ischial tuberosity 2
• Superior ends of bursal sacs abutting the infero-medial aspect of the ischial tuberosity 2
• Variable signal intensity on T1-WI (17.6% hypo-intense, 58.9% iso-intense, 23.5% hyper-intense) 2
• Hyperintense signal on T2-WI (100% of cases) 2
• Heterogeneity depending on blood-fluid levels and septae within bursae 2

Contrast Enhancement

• IV contrast is generally not required for routine evaluation 1
• When used, contrast enhancement shows smooth (29.4%) or irregular (70.6%) inner wall of bursae due to synovial proliferation and septation 2

Diagnostic Accuracy

• MRI has excellent sensitivity for detecting soft tissue inflammation and fluid collections 1
• Characteristic location and cystic appearance on MRI are diagnostic 2
• MRI helps differentiate ischial bursitis from other soft tissue masses and tumors 3

Treatment Options

First-Line Treatment

• Conservative management:
  • Rest and activity modification
  • NSAIDs
  • Physical therapy with eccentric strengthening exercises
  • Deep transverse friction massage 4

Second-Line Treatment

• Image-guided injections:
  • Corticosteroid mixed with local anesthetic
  • Fluoroscopically guided injections provide superior pain relief (86.25% improvement) compared to landmark-based injections (55% improvement) 5
  • Ultrasound guidance recommended for accurate needle placement 4

Injection Technique

• Patient position: Lateral decubitus with affected side up
• Needle: 22-25 gauge, 1.5-inch (3.8 cm) length (2-inch/5 cm for obese patients)
• Approach: 90° angle to skin
• Aspiration before injection to ensure no blood return 4

Surgical Intervention

• Reserved for cases refractory to conservative treatment (3-6 months)
• Options include:
  • Endoscopic approach (less invasive, quicker recovery)
  • Open decompression for severe cases 4

Special Considerations

• Patients with inflammatory diseases have poorer response to conservative treatment (66.7% non-response rate vs 10.3% in those without inflammatory disease) 6
• Caution needed in differential diagnosis as ischial bursitis can mimic soft tissue tumors 3

Treatment Algorithm

1. Initial radiographs to rule out bony pathology
2. MRI for confirmation of diagnosis
3. Begin conservative treatment for 4-6 weeks
4. If no improvement, proceed to image-guided corticosteroid injection
5. For persistent symptoms beyond 3-6 months, consider surgical referral
6. More aggressive early intervention for patients with underlying inflammatory diseases

By following this evidence-based approach to diagnosis and treatment, clinicians can effectively manage ischial bursitis and improve patient outcomes.