What is the best initial imaging for a patient with hyperuricemia and foot pain?

Best Initial Imaging for Hyperuricemia with Foot Pain

Plain radiography of the foot (weight-bearing views) is the best initial imaging study for a patient with elevated uric acid and foot pain. 1

Rationale for Initial Radiography

The American College of Radiology establishes conventional foot radiography as the standard first-line imaging for chronic foot pain of unknown etiology, regardless of the suspected underlying cause. 1 This approach serves multiple critical purposes:

• Excludes alternative diagnoses that may mimic gout, including fractures, osteoarthritis, stress injuries, tarsal coalitions, and other osseous abnormalities that require different management strategies 1, 2
• Provides baseline assessment of joint architecture and bone integrity before considering more advanced imaging 1
• Cost-effective and widely available with minimal radiation exposure compared to CT 1

Weight-bearing views are specifically recommended when feasible, as they optimize visualization of foot structures and joint alignment. 2, 3

When Advanced Imaging Is Indicated

If radiographs are negative or equivocal but clinical suspicion for gout remains high, consider the following algorithm:

For Suspected Acute Gout or Tophaceous Disease

Dual-energy CT (DECT) is highly accurate for detecting uric acid crystal deposits:

• Demonstrates 100% sensitivity and 79-89% specificity for identifying intraarticular and periarticular uric acid crystals 4
• Provides definitive non-invasive diagnosis without need for joint aspiration 4
• Particularly valuable when joint aspiration is unsuccessful, contraindicated, or refused 4

For Suspected Soft Tissue Involvement

Ultrasound can detect subclinical urate deposits and inflammation:

• Identifies tophi in tendons, synovium, and soft tissues in approximately 34% of asymptomatic hyperuricemic patients 5
• Demonstrates the "snowstorm" appearance of synovial fluid when urate crystals are present 6
• Detects increased vascularity indicating active inflammation in 23% of cases 5
• Allows dynamic assessment and can guide therapeutic interventions 7

MRI without contrast is appropriate for:

• Evaluating occult fractures or stress injuries if radiographs are negative 1
• Assessing soft tissue pathology including tendon tears, plantar fasciitis, or nerve entrapment 1
• Detecting bone marrow edema or early erosive changes 7

Critical Clinical Pearls

Hyperuricemia Does Not Equal Gout

• Only 15-20% of hyperuricemic patients develop clinical gout 6
• Asymptomatic hyperuricemia may show subclinical crystal deposition on ultrasound without causing symptoms 5
• The traditional SUA threshold of 6.8 mg/dL for crystal precipitation may be lower than previously thought (potentially as low as 4.8 mg/dL), with gender differences noted 6

Common Diagnostic Pitfalls to Avoid

• Do not skip radiographs even with known hyperuricemia—other pathology must be excluded first 1
• Do not order ankle radiographs for foot pain—standard foot views are required for proper visualization of midfoot and forefoot structures 2
• Do not rely solely on radiographs for stress fractures, which have only 12-56% sensitivity on plain films 1, 2
• Ensure proper views are obtained: anteroposterior, lateral, and oblique projections are standard 2, 8

When Joint Aspiration Remains Gold Standard

Despite advanced imaging capabilities, synovial fluid analysis with polarized light microscopy remains the definitive diagnostic test for acute gout when feasible. 4 However, DECT provides an excellent non-invasive alternative when aspiration is not possible or yields insufficient fluid. 4