What type of ultrasound should be requested for a patient, particularly an adult woman with a history of repetitive strain or overuse injury, suspected of having de Quervain's tendinitis?

Ultrasound Imaging for De Quervain's Tendinitis

Request a high-resolution musculoskeletal ultrasound of the wrist, specifically targeting the first dorsal compartment with both longitudinal and transverse views to evaluate for tenosynovitis and identify subcompartmentalization. 1

Specific Ultrasound Protocol

The American College of Radiology identifies ultrasound as the most appropriate imaging modality for suspected de Quervain's disease, particularly because preoperative identification of septations or subcompartmentalization within the first dorsal compartment can directly affect surgical management. 1

Technical Specifications

• Transducer frequency: Use high-frequency transducers of 10 MHz or higher to detect even minor tenosynovitic lesions 1
• Patient positioning: Sitting position with the hand placed on top of the thigh or examining table 1
• Standard scanning planes required:
  • Dorsal transverse scan (radial aspect) 1
  • Dorsal longitudinal scan (radial aspect) 1
  • Dynamic examination with active thumb movement 1

Key Diagnostic Features to Identify

Ultrasound should specifically evaluate for:

• Thickened, hypoechoic tenosynovial sheath surrounding the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons 2, 3
• Fluid within the tendon sheath indicating active inflammation 3
• Subcompartmentalization or septations within the first dorsal compartment, which occurs in approximately 52% of cases and significantly impacts treatment success 4, 5
• Anatomic variations including accessory tendons 2

Clinical Utility Beyond Diagnosis

Ultrasound serves three critical functions: confirming the clinical diagnosis, identifying anatomical variations that affect treatment planning, and guiding corticosteroid injections for improved accuracy. 2, 4

Research demonstrates that ultrasound-guided injections achieve 97% partial or complete symptom resolution at 6 weeks, superior to blind injection techniques, because the ultrasound ensures proper injection into all subcompartments when present. 4 Multiple subcompartments were identified in 52% of cases, and all patients who experienced symptom recurrence had subcompartments that may have been missed without ultrasound guidance. 4

When Ultrasound May Not Be Sufficient

Plain radiographs are not necessary for typical presentations but should be obtained if you need to exclude bony pathology such as first carpometacarpal joint osteoarthritis, scaphoid fracture, or other osseous abnormalities. 2

MRI is not routinely indicated for straightforward de Quervain's tenosynovitis but becomes appropriate when the diagnosis remains unclear after ultrasound or when multiple differential diagnoses (intersection syndrome, inflammatory arthritis) need exclusion. 2

Common Pitfalls to Avoid

• Failing to identify subcompartmentalization: This is the most critical error, as incomplete injection or surgical release of all subcompartments leads to treatment failure 4, 5
• Not using ultrasound for injection guidance: Blind injections have variable response rates because they may miss the compartment or fail to access all subcompartments 4
• Ordering MRI as first-line imaging: This is unnecessary for typical presentations and does not provide the real-time anatomical detail needed for injection guidance 1, 2