Children's health Diagnostics Ultrasound

Pediatric thymus ultrasound: indications, procedure, prices in USA

Tatyana Kirillova - Diagnostics Specialist
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Medically reviewed: 1, February 2024

Read Time:6 Minute

Pediatric Thymus Ultrasound: indications and procedure

Pediatric thymus ultrasound is a non-invasive cranial ultrasound study of the thymus using ultrasonic waves. It provides information on the size, shape, location and structure of the thymus gland. It is usually performed in childhood to identify thymomegaly. Infant ultrasound is carried out in a planned manner. In older children, indications for scanning are frequent severe colds, unexplained subfebrile condition and allergic reactions.

Adult patients are prescribed for suspected thymoma, T-cell lymphoma, other types of thymus neoplasia, and some rare syndromes (eg, Di Georg’s syndrome). The procedure does not require special preparation and does not have a harmful effect on the patient’s body.

Pediactric Thymus ultrasound key takeaways

Pediatric thymus ultrasound is a non-invasive and radiation-free imaging technique that can be used to evaluate the size, shape, and structure of the thymus gland in infants and children. The thymus is a lymphoid organ located in the anterior mediastinum, which is responsible for the production and maturation of T-cells, a type of white blood cell that plays a key role in the immune system.

The thymus is relatively large at birth and grows until puberty, after which it undergoes involution and is replaced by fatty tissue.

Here are three key takeaways about pediatric thymus ultrasound:

  1. Pediatric thymus ultrasound can be used to measure the normal size and growth of the thymus gland in different age groups. According to a study by Adam and Ignotus (1993), the normal length of the thymus gland in infants and children ranges from 2.5 to 4.5 cm, and the normal width ranges from 1.5 to 2.5 cm.
  2. The normal size of the thymus can vary depending on the gender, body weight, and nutritional status of the child. Pediatric thymus ultrasound can also detect any abnormalities in the shape and symmetry of the thymus, such as unilobed, trilobed, X-shaped, or inverted V-shaped thymus.
  3. Pediatric thymus ultrasound is often used to diagnose and monitor various thymic disorders in infants and children. Some of the common thymic disorders that can be detected by ultrasound are:
  • thymic hypoplasia, which is a congenital condition characterized by a small or absent thymus, resulting in immunodeficiency and increased susceptibility to infections;
  • hyperplasia, which is an acquired condition characterized by an enlarged thymus, usually due to chronic stimulation by antigens, hormones, or drugs;
  • cysts, which are benign fluid-filled sacs that can develop in the thymus, causing compression of the surrounding structures;
  • thymic tumors, which are malignant or benign neoplasms that can arise from the thymic epithelial cells or the lymphoid cells;
  • infections, which are inflammatory processes that can affect the thymus, causing fever, pain, and abscess formation.

Indications for an ultrasound of thymus gland

Ultrasonography of the thymus belongs to the category of screening studies. Can be carried out both in the order of preventive examination, and when there are special indications of a violation of the body. Prophylactic ultrasound may be administered to children under the age of 1 year.

For older children, it is recommended that the study be conducted during the period of registration in a preschool institution.

As evidence for unscheduled ultrasound of the thymus gland in children, more than 10 catarrhal diseases are treated during the year and a large number of complications (bronchitis, sinusitis, pneumonia) that have arisen against the background of acute infections.

The study is also performed in the presence of severe diathesis, dysbacteriosis, pollinosis, urticaria, bronchial asthma and a predisposition to allergic reactions.

Indication is a prolonged or repeated increase in temperature to subfebrile digits and an increase in lymph nodes.

Significant thymomegaly can become a cause of compression of the vagus nerve, vascular bundle and neighboring organs, so children are sent to the ultrasound of the thymus with profuse regurgitation, severe noisy breathing, pertussis-like cough, heart rhythm disturbances and the appearance of a vascular network on the skin of the chest.

Adult procedure is appointed at the appearance of clinical or rentgenological signs of thymus pathology. There are no contraindications.

Preparing for ultrasound of thymus gland

Special preparation for the study is not required. In order to calculate the normal mass of the thymus gland, it is essential to first determine the weight of the child prior to undergoing an ultrasound. This calculation takes into consideration the patient’s body parameters. Parents are advised to choose easily removable clothes for the child and prepare napkins or a small towel to remove the remnants of the gel from the skin.

The quality of the diagnostic data directly depends on the behavior of the child during the procedure, so the experts advise parents to soothe the baby in advance and try to create a favorable emotional atmosphere. You can take a toy with you to distract attention.

Pediatric Thymus Ultrasound: Method of conducting

Newborn ultrasound is carried in the position on the back, placing a small roller under the neck. When there are signs of anxiety in young children, the scan is performed in the supine position or sitting on the lap of the parent. Patients older than two years are examined in standing position.

During the procedure, a water-based gel is applied to the baby’s breast, ensuring that there is no air gap between the sensor and the skin of the patient. From the sensor, information is sent to the monitor.

Ultrasound diagnostics performs scanning in the transverse and longitudinal planes, determines the localization, size and shape of the organ, evaluates the contours, echogenicity and homogeneity of the thymus structure, and also reveals additional inclusions (if any).

The duration of the procedure is 10-15 minutes. After its completion, remove the gel from the baby’s chest. Then the specialist conducts special calculations to evaluate the results of the study.

Ultrasound of thymus gland: Interpretation of results

Normal thymus is an organ with medium echogenicity, smooth contours and a homogeneous structure. The gland is clearly delineated from other anatomical formations and soft tissues of the anterior mediastinum. The posterior border of the organ is even. In the presence of tumors of the thymus gland in the course of ultrasound revealed areas with altered echogenicity, heterogeneity of the structure, change in the size and shape of the gland.

With Di Georgi syndrome, thymus aplasia is determined, myasthenia gravis in some patients shows thymoma.

For a more accurate evaluation, calculations are made using the patient’s weight, length, width, and thickness of the organ parts obtained during echography. The volume and mass of each lobe, as well as the total volume and mass of the gland, are determined based on their measurements. At the final stage, determine the thymic index – the mass of the thymus is divided by the weight of the child’s body, then multiply the result by 100%.

The index is compared with the index in a special table. Normally, the mass of the thymus gland should be 0.3% of the child’s body weight.

With an increase in this indicator speak of thymomegaly, with a decrease in the incompatibility of the size of the gland with the age of the child. With the results of ultrasound of the thymus, you should consult a pediatrician, a therapist or an immunologist.

A significant increase in the thymic index is an occasion for further investigation. The child is referred to a chest X-ray, the results are calculated by the cardiotomicotor index and the vasocardial index to determine the degree of thymomegaly.

The ultrasound and radiographic data are supplemented by the results of laboratory tests conducted to assess the state of the immune and endocrine systems. With thymomegaly of the 1st degree, special medical measures are not required, with an increase in the organ of the second and third degree, medication is prescribed.

Cost of pediatric thymus ultrasound in USA

The price of the thymus ultrasound is determined by the medical organization, based on the general price policy, the category of equipment used, the qualification of the diagnostician. The price of an ultrasound of the thymus gland in USA can be different depending on the age of the subject: different price lists for services are used for children and adults.

Execution of echographic images and involvement of experts in interpreting the results raises the cost of diagnosis. The pricing factors can also be the use of additional modes of organ visualization: three-dimensional scanning, color Doppler mapping, etc.

          
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