Ultrasound thyroid examination is a non-invasive diagnostic technique that produces real-time images of the thyroid tissue using high-frequency sound waves. This examination is used to evaluate thyroid nodules, swelling, or other abnormal structures, assisting physicians in determining the nature of the lesions. Its advantages include being non-invasive and repeatable, making it a common initial screening tool for thyroid diseases.
The procedure is performed by a radiologic technologist. Patients are required to lie flat with their neck exposed. The examination takes approximately 15-30 minutes. The resulting images display tissue density, blood flow distribution, and shape abnormalities, providing critical information for subsequent treatment planning.
Ultrasound thyroid examinations are categorized into "B-mode ultrasound" and "Color Doppler blood flow imaging." B-mode provides black-and-white images of tissue structure, while Color Doppler tracks blood flow dynamics. The sound waves emitted by the device penetrate the tissue, and the reflected waves are converted by a computer into two-dimensional or three-dimensional images.
This technology utilizes differences in tissue reflection of sound waves to produce images, with no ionizing radiation exposure risk. When evaluating nodules, features such as border clarity, calcification distribution, and blood flow concentration are observed, which aid in differentiating benign from malignant lesions.
This examination is primarily used for assessing the morphology of thyroid nodules, determining the extent of thyroid swelling, and observing signs of subacute or Hashimoto's thyroiditis inflammation. It is often performed when clinical palpation detects abnormalities or when blood tests show abnormal TSH levels.
Additionally, ultrasound is the preferred diagnostic tool for postoperative follow-up of thyroid cancer, enlarged lymph nodes, or suspected thyroid cysts. In some cases, it is combined with radioactive iodine scans to improve diagnostic accuracy.
During the examination, patients should remove neck jewelry, apply gel, and gently press the probe against the skin to scan. The concept of dosage does not apply, but the physician may adjust the scanning angle and depth based on nodule size or thyroid shape. 3D ultrasound may require more detailed multi-angle scanning.
No fasting or special preparation is necessary, but patients should avoid wearing high-collared clothing. Special populations such as children or patients with involuntary movements may require brief sedation, but this is an uncommon procedure.
Compared to CT scans, ultrasound involves no ionizing radiation, making it safer for pregnant women and minors. Its high resolution can detect small nodules less than 5mm, which other imaging techniques may miss.
The vast majority of patients experience only mild discomfort from probe pressure, with some experiencing temporary neck pain due to overstretching. The procedure itself does not cause tissue damage, but patients with metal implants or electronic cochlear devices should have safety evaluated by a physician beforehand.
Important Warning: The results should be interpreted in conjunction with clinical symptoms and blood tests. Imaging alone cannot definitively exclude cancer. In certain cases, further cytological examination is necessary.
Patients should inform healthcare providers in advance if they have a history of neck surgery, implanted electronic medical devices, or are pregnant. Removing metal jewelry before the scan helps prevent image interference.
Contraindications include severe neck burns or open wounds, which may necessitate alternative imaging methods. Patients allergic to ultrasound gel should inform staff beforehand to use alternative gels or premedication.
Ultrasound itself does not interact with medications or surgeries, but the findings may influence subsequent treatment choices. For example, suspicious malignant nodules may require radioactive iodine therapy or surgery.
It has a procedural relationship with fine-needle aspiration (FNA), typically performed after ultrasound localization. When combined with radiological examinations such as nuclear medicine scans, it provides both structural and functional information.
Multiple studies worldwide show that ultrasound has a sensitivity exceeding 95% for thyroid nodules, capable of distinguishing cystic from solid nodules. The American College of Radiology states that combining ultrasound features with grading systems (such as TI-RADS) can increase the accuracy of malignancy prediction to 80-90%.
In clinical practice, ultrasound-guided FNA increases biopsy accuracy from 60% to 95%, making it the preferred method in international treatment guidelines. Long-term follow-up studies indicate that regular ultrasound examinations can detect early growth trends of lesions.
Radioactive iodine scans can evaluate thyroid function but involve radiation exposure. CT scans can show tissue layers but have higher radiation doses and costs. MRI offers excellent soft tissue resolution but requires longer scan times and is unsuitable for patients with metal implants. Invasive procedures like FNA are typically performed after ultrasound detects suspicious lesions.
Generally, no fasting or medication discontinuation is necessary before a thyroid ultrasound. It is recommended to wear a loose, open-neck top to expose the neck area. If other blood tests are scheduled simultaneously, follow the specific preparation instructions. Patients on oral anticoagulants or with special medical histories should inform staff in advance.
What sensations might I experience during the procedure? Will it cause pain or discomfort?The ultrasound examination is painless. Patients lie flat with their neck exposed, and the probe gently presses against the skin for scanning. Some may feel slight pressure from the probe, but most tolerate it well. The procedure lasts about 10-30 minutes, depending on the complexity of the lesion.
Are there any precautions after the examination? Do I need to rest?Patients can resume normal activities and diet immediately after the scan. If a fine-needle aspiration biopsy was performed, apply pressure to the wound for 15-20 minutes and avoid strenuous activity as instructed. For abnormal results, the physician will explain follow-up or treatment plans.
How long does it take to receive the report? How accurate are the results?Reports are typically available within 1-3 working days, with more complex cases possibly taking longer. The accuracy depends on the experience of the operator and the quality of the equipment. It is recommended to have the examination performed by a radiologist or endocrinologist. If there are concerns about the results, a second opinion or cross-referencing with other tests can be requested.
Does the ultrasound equipment vary between hospitals affect the results? How should I choose a medical facility?While equipment resolution can influence detail display, professional physicians can compensate for some differences. When choosing a facility, prioritize: 1) operation by a thyroid specialist 2) use of high-frequency probes (>7MHz) 3) provision of real-time image reporting. Public hospitals or specialized clinics with standardized procedures are generally reliable.
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