A neck ultrasound is a non-invasive medical imaging examination that uses high-frequency sound waves to create real-time pictures of the structures inside the neck. This painless and safe procedure involves placing a small transducer device against the skin, which transmits the sound waves and records the echoes they produce. The resulting images allow a doctor to visualize soft tissues that cannot be seen clearly on a standard X-ray. It is a common procedure used to investigate symptoms or findings, such as lumps, swelling, or abnormal blood tests, identified during a physical examination.
Examination of the Thyroid and Parathyroid Glands
A primary focus of a neck ultrasound is the detailed examination of the butterfly-shaped thyroid gland, which sits at the base of the neck. The test assesses the gland’s overall size, shape, and internal texture, looking for diffuse enlargement or changes that might suggest conditions like thyroiditis. High-resolution imaging is effective for detecting and characterizing thyroid nodules.
A radiologist carefully examines any nodules, noting whether they are predominantly fluid-filled (cystic) or composed of solid tissue, as well as measuring their size and defining their borders. Features that may suggest a higher risk, such as a shape that is “taller-than-wide,” irregular margins, or microcalcifications, are documented. The combination of these visual characteristics helps determine the next steps, often using standardized risk stratification systems.
The ultrasound also attempts to visualize the four parathyroid glands, which are located behind or adjacent to the thyroid and regulate calcium levels. Normal parathyroid glands are often too small to be seen. However, the ultrasound is effective at identifying them when they become abnormally enlarged due to a condition like hyperparathyroidism. An enlarged parathyroid gland, often a benign tumor called an adenoma, typically appears as an oval, well-defined mass that is darker (hypoechoic) than the surrounding thyroid tissue.
Assessing Blood Flow and Major Neck Vessels
The neck ultrasound incorporates Doppler technology, which uses sound waves to measure the speed and direction of blood flow within the major vessels. This is important for evaluating the carotid arteries, which supply blood to the brain, and the jugular veins, which return blood from the head. The examination of the carotid arteries is often referred to as a carotid duplex scan.
The Doppler component is used to detect and quantify stenosis, which is the narrowing of an artery caused by plaque buildup. Measurements like the Peak Systolic Velocity (PSV) and End-Diastolic Velocity (EDV) are taken to calculate the percentage of arterial blockage. For example, a PSV exceeding 230 cm/second in the internal carotid artery indicates a severe blockage of 70% or more.
The scan also provides a structural assessment of the plaque, noting if it appears smooth and stable or irregular and soft (hypoechoic). Irregular plaque suggests a higher risk of breaking off and causing a stroke. The jugular veins are also examined to ensure they are fully compressible. The presence of a non-compressible segment or visible internal echoes can indicate a clot, or thrombosis. This look at the vessel structure and function is important for evaluating stroke risk and circulatory health.
Evaluating Lymph Nodes and Soft Tissue Masses
Beyond the glands and vessels, the neck ultrasound is the preferred method for examining the lymph nodes located throughout the neck. These nodes swell in response to infection or inflammation, and the ultrasound helps distinguish between benign reactive enlargement and potentially more concerning changes. A normal lymph node is typically oval with a bright center (echogenic hilus) and a clear blood supply at the center.
A node that is more rounded, lacks a visible central hilus, or shows blood flow patterns concentrated around the edge may be flagged as needing further investigation. The imaging provides information on the size and internal architecture of the nodes, using a ratio of its short to long axis to assess its roundness. These characteristics guide the decision on whether a biopsy is warranted.
The ultrasound is also used to characterize other types of soft tissue masses that may be felt as a lump by the patient or physician. This includes issues related to the salivary glands, which can be affected by stones or tumors, or various types of congenital cysts. For masses like lipomas, the ultrasound can confirm the composition and location of the tissue, helping to provide a definitive diagnosis without the need for more invasive testing.
Soft Tissue Masses
- Salivary gland issues (stones or tumors)
- Branchial cleft cysts
- Thyroglossal duct cysts
- Lipomas (benign fatty lumps)
Interpreting Ultrasound Findings and Follow-Up
Following the procedure, a radiologist or other physician specializing in imaging interpretation analyzes the images collected during the neck ultrasound. The specialist generates a detailed report summarizing the size and characteristics of all identified structures, including the specific measurements and risk stratification of any nodules or plaques. This technical report is then sent to the referring physician, who ordered the test.
The referring physician uses this information, alongside the patient’s clinical history and symptoms, to determine the appropriate next steps. Findings that are clearly benign, such as small, simple cysts or stable, non-obstructive plaque, may only require routine monitoring or no further action. However, suspicious findings might prompt a recommendation for a follow-up ultrasound in several months or an immediate, ultrasound-guided biopsy to obtain a tissue sample for definitive diagnosis.