Imaging to detect parathyroid adenoma is typically which modality?

• A. Ultrasound only
• B. CT or MRI
• C. X-ray
• D. PET scan

Answer: (B)

The key idea is preoperative localization of abnormal parathyroid tissue. Ultrasound can find some superficial adenomas, but it often misses deeper or mediastinal glands and is highly operator-dependent. Cross-sectional imaging with CT or MRI offers superior anatomic detail, allowing precise localization of even small adenomas behind the thyroid or in the mediastinum. CT provides excellent spatial resolution and contrast-enhanced detail, while MRI gives strong soft-tissue contrast and is useful when iodine-based contrast is a concern or when evaluating difficult-to-reach locations. X-ray isn’t sensitive for parathyroid tissue, and PET is not routinely used for initial localization. Therefore, CT or MRI is typically the imaging modality for detecting a parathyroid adenoma.