Thyroid nodule, as the name suggests, is a mass located inside the thyroid gland. It is a mass produced by abnormal proliferation of thyroid cells and can be detected by ultrasound as distinct from surrounding tissues. Thyroid nodules are a common thyroid disease that can present with multiple lesions simultaneously, such as thyroid degeneration, inflammation, autoimmune diseases, tumors, etc. As long as a clear diagnosis of their nature is not made, they can be referred to as thyroid nodules. In recent years, the incidence rate of thyroid nodules in the world has increased significantly year by year. Except for the rising diagnostic rate, other factors are still unclear. Therefore, this article will elaborate on how ultrasound can detect thyroid nodules. Only after a clear diagnosis can corresponding treatment measures be formulated based on the patient's condition.
1. Diagnosis of thyroid nodules
Thyroid nodules refer to lumps within the thyroid gland that can move up and down with swallowing movements, and are a common clinical disease. At present, the detection rate of thyroid nodules in clinical practice is about 80% -90%, and most of them are benign nodules. The detection rate of thyroid nodules by ultrasound mainly depends on factors such as their size, shape, boundaries, internal echoes, and the presence or absence of calcification. The normal thyroid gland is round or oval in shape, with clear boundaries with surrounding tissues. When the following situations occur: (1) diameter exceeds 3cm; (2) fine sand like calcification appears within the nodule; (3) Irregular nodule morphology and unclear boundaries; (4) The internal echo of the nodule is uneven, presenting as punctate strong echo or no echo; (5) Echo attenuation or disappearance behind the nodule; (6) Nodules combined with calcification.
2. How to detect thyroid nodules by ultrasound
2.1 Size of nodules
Generally, nodules smaller than 1cm are considered as small nodules. Thyroid nodules smaller than 1cm may be benign and generally do not require surgical treatment. Regular follow-up examinations are sufficient; Thyroid nodules larger than 1cm require further clarification of their benign and malignant nature to determine whether surgical resection is necessary; Thyroid nodules have different manifestations and properties on ultrasound. The size of thyroid nodules determined by ultrasound mainly depends on their echogenicity. The echogenicity of nodules can be solid, cystic, or mixed. If the echogenicity is stronger than that of surrounding tissues, and the internal echogenicity is low and disordered, it may indicate solid or cystic. During ultrasound examination, the following points should be noted: (1) whether the nodule edge is smooth; (2) Whether there is bleeding, calcification, and other tissue structures inside the nodule; (3) The uniformity of internal echoes in nodules.
2.2 Morphology of Nodules
Nodule morphology is divided into two types: nodular and cystic nodules. There is no necessary relationship between the size of nodules and their benign or malignant nature. Under normal circumstances, benign nodules are often circular or elliptical in shape, while malignant nodules are usually irregular and have an aspect ratio generally greater than 1. However, it is worth noting that if there are smaller upright nodules, it is often papillary carcinoma.
2.3 Boundary of nodules
The boundary of thyroid nodules refers to the relationship between thyroid nodules and surrounding tissues, as well as normal thyroid tissue. The boundary between thyroid tissue and surrounding normal tissue is clear, and it is more common in solitary nodules; The clear and fuzzy boundary of nodules is an important feature for distinguishing between benign and malignant, especially when the internal echoes of nodules are uneven. Ultrasound physicians should be proficient in the key points of differential diagnosis. Uneven echo inside the nodule: If the echo inside the nodule is uneven, it is due to the incorrect position of the thyroid nodule or calcification inside the nodule. The internal echo of malignant nodules is uneven, mainly low echo, often accompanied by calcification, punctate strong echo or patchy hypoechoic; Benign nodule: uniform internal echo, clear boundary, mainly high echo, may be accompanied by calcification.
2.4 Echo of nodules
During ultrasound examination, the echo of nodules is a very important ultrasound sign. The shape, distribution, and strength of nodule echoes are related to the nature of the nodule. The morphology of nodule echoes is related to their boundaries, aspect ratio, internal structure (including calcification, vacuoles, etc.), and blood flow signals. When the echo of the nodule is uniform or low, it is mostly a benign nodule. When the echo is distributed in a nodular or star like pattern, it is often a malignant nodule and requires timely intervention. When the echo of a nodule appears as low, medium, high, or low medium high, it is mostly a benign nodule.
2.5 Calcification and Blood Flow of Nodules
Benign calcified areas are mainly coarse, patchy, and arc-shaped, usually caused by local "malnutrition" of the thyroid gland. Calcifications with malignant tendencies are often small, sandy or clustered calcifications, which are characteristics of thyroid cancer. Benign nodules have abundant blood flow, usually showing a circular distribution. If the patient's thyroid tumor is small, star like blood flow can be seen. Thyroid tumors are larger, with richer blood flow and more irregular distribution.
3. Summary
Currently, thyroid nodules can be treated through hormone suppression therapy, sclerotherapy, and surgical intervention. Patients should seek medical attention promptly when experiencing similar symptoms, undergo ultrasound examination under the guidance of a physician, receive timely treatment, and promote disease recovery.