Ultrasound-Guided Ethanol Injection (PEI)

Benign thyroid cysts are fluid-filled nodules within the thyroid. Physicians can use ultrasound-guided aspiration to drain the cyst and test the fluid for cells. Aspiration provides immediate relief of cyst swelling; however, approximately 50% of patients experience recurrence within two years.
Current treatment options include:

1. Repeat aspiration
2. Ethanol injection
3. Radiofrequency ablation
4. Surgery

For patients with recurrent thyroid cysts after repeated aspiration, ultrasound-guided percutaneous ethanol injection (PEI) offers an alternative to surgery.
Under local anesthesia and ultrasound guidance (see image below), ethanol is injected precisely into the cyst. The ethanol induces inflammation of the cyst wall, causing it to collapse and shrink or disappear. Other than brief discomfort, there are no significant side effects.