What is the recommended imaging approach for patients with hyperparathyroidism (elevated Parathyroid Hormone (PTH))?

Imaging Approach for Hyperparathyroidism

For patients with elevated PTH (hyperparathyroidism), the recommended initial imaging approach is a combination of neck ultrasound and sestamibi dual-phase scan with SPECT or SPECT/CT. 1, 2

First-Line Imaging Options

Ultrasound (US)

• Sensitivity: 76-80% for parathyroid adenoma detection
• Positive predictive value (PPV): 93%
• Advantages:
  • No radiation exposure
  • Low cost
  • Real-time imaging
  • Can simultaneously evaluate thyroid pathology
  • Can detect thyroid nodules requiring further evaluation (found in 18.4% of hyperparathyroidism patients) 3
• Limitations:
  • Operator-dependent
  • Poor detection of ectopic glands (only 7-32% sensitivity for ectopic glands) 1
  • Limited visualization of mediastinal glands

Sestamibi Dual-Phase Scan with SPECT/CT

• Sensitivity: 88-93% when combined with SPECT/CT
• Advantages:
  • Superior for detecting ectopic glands
  • Provides both functional and anatomical information
  • Higher sensitivity than planar imaging alone
• Limitations:
  • Radiation exposure
  • Lower sensitivity in multigland disease
  • False negatives with small adenomas

Second-Line Imaging Options (when first-line is negative or discordant)

4D-CT (CT neck without and with IV contrast)

• Sensitivity: 62-88%
• PPV: 84-90%
• Particularly useful when ultrasound and sestamibi are negative or discordant 2
• Provides excellent anatomical detail and can detect small adenomas

MRI Neck

• Sensitivity: 63-93% (higher with dynamic sequences)
• PPV: 85-100%
• Useful alternative when radiation exposure is a concern
• Particularly valuable in reoperative cases 1

18F-Fluorocholine PET/CT

• Emerging as the most sensitive method for parathyroid adenoma detection
• Particularly valuable in multigland disease and tertiary hyperparathyroidism 4
• Limited by cost and availability

Third-Line Option (when all other imaging is negative or discordant)

Selective Venous Sampling for PTH

• Sensitivity: 40-93%
• Reserved for reoperative cases or when non-invasive imaging is inconclusive 1, 2
• Invasive procedure with potential complications
• Can help regionalize the location of hyperfunctioning parathyroid tissue

Imaging Algorithm Based on Hyperparathyroidism Type

Primary Hyperparathyroidism (PHPT)

1. Start with neck ultrasound AND sestamibi scan with SPECT/CT
2. If concordant (70% of cases): Proceed to surgery with 97% accuracy 5
3. If discordant (30% of cases): Add 4D-CT or MRI
4. If still inconclusive: Consider venous sampling

Secondary/Tertiary Hyperparathyroidism (SHPT/THPT)

1. Start with neck ultrasound (though less valuable than in PHPT)
2. Consider sestamibi with SPECT/CT, though sensitivity is lower due to multigland disease
3. For tertiary hyperparathyroidism, 18F-fluorocholine PET/CT may be preferred if available 4

Important Considerations

• Imaging does not confirm or exclude the diagnosis of hyperparathyroidism - biochemical confirmation is required first 1
• Concordant results from multiple imaging modalities increase confidence in localization
• In secondary hyperparathyroidism, imaging has limited value as bilateral neck exploration is typically required due to multigland disease 1, 3
• Ultrasound can identify concurrent thyroid pathology that may require attention during surgery 3
• For recurrent or persistent hyperparathyroidism after surgery, all first-line imaging options remain appropriate but may have lower sensitivity 1

By following this evidence-based imaging approach, clinicians can optimize surgical planning, potentially allowing for minimally invasive parathyroidectomy rather than bilateral neck exploration, which leads to shorter operating times, faster recovery, and decreased costs while maintaining high cure rates.