Sestamibi parathyroid scan

Sestamibi parathyroid scan

A Sestamibi parathyroid scan is a nuclear medicine imaging technique used to localize parathyroid adenomas and hyperfunctioning parathyroid glands. This scan is particularly useful in the diagnosis and management of primary hyperparathyroidism, a condition characterized by the overproduction of parathyroid hormone (PTH) due to one or more hyperactive parathyroid glands.

Procedure

The procedure involves the intravenous injection of a small amount of a radioactive tracer called Technetium-99m sestamibi. This tracer is preferentially taken up by overactive parathyroid tissue. After the injection, the patient undergoes a series of scintigraphic images using a gamma camera at different time intervals, typically at 10 minutes and 2 hours post-injection. The images help to identify the location of hyperfunctioning parathyroid tissue.

Indications

A Sestamibi parathyroid scan is indicated in patients with:

• Primary hyperparathyroidism
• Secondary hyperparathyroidism
• Tertiary hyperparathyroidism
• Persistent or recurrent hyperparathyroidism after surgery

Interpretation

The interpretation of the scan involves comparing early and delayed images. Hyperfunctioning parathyroid glands typically show increased uptake of the tracer on early images and retain the tracer on delayed images, whereas normal thyroid tissue washes out the tracer more quickly.

Advantages

• Non-invasive
• High sensitivity and specificity for detecting parathyroid adenomas
• Useful in preoperative planning for minimally invasive parathyroidectomy

Limitations

• False positives can occur due to uptake in other tissues such as thyroid nodules or lymph nodes
• Not always able to detect multiglandular disease

Related Procedures

• Ultrasound
• 4D-CT scan
• MRI

See also

• Parathyroidectomy
• Parathyroid hormone
• Hyperparathyroidism