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Changes in the thymus gland with age: A sonographic evaluation
Seyed Ali Alamdaran1, Masoud Mahdavi Rashed1, Mohammad Yekta1
1Department of Radiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
Insights
Ultrasound can visualize the thymus in children of all ages. The thymus echo-texture changes with age, but its volume does not significantly correlate with age or sex.
Area of Science:
- Pediatric Radiology
- Medical Imaging
- Anatomy
Background:
- Ultrasound evaluation of the thymus in children presents challenges, particularly in differentiating normal variations from abnormalities.
- Few studies have comprehensively investigated age-related sonographic changes in the pediatric thymus.
Purpose of the Study:
- To investigate age-specific sonographic changes in the normal thymus of healthy children.
- To establish reference sonographic features of the pediatric thymus across different age groups.
Main Methods:
- A cross-sectional study involving 118 healthy children, categorized into six age groups.
- Sonographic assessment of thymic features including volume, position, symmetry, and echo-texture using ultrasound.
- Data collection from the suprasternal view, recording thymic visibility and characteristics.
Main Results:
- The thymus was consistently visualized via ultrasound in all age groups from the suprasternal view.
- Thymic echo-texture demonstrated distinct age-related patterns: hypoechoic (below 2-3 years), echogenic foci/starry sky (2-14 years), and uniform/geographic hyperechoic (above 14 years).
- No significant correlation was found between age and sex with total thymic volume; mean volume was 21.3 ± 10.5 mm.
Conclusions:
- Ultrasound is a reliable modality for visualizing the pediatric thymus across all ages.
- The echo-texture of the normal thymus exhibits significant age-dependent variations, aiding in its sonographic characterization.
- Thymic volume shows no significant correlation with age or sex, reinforcing ultrasound's role in pediatric thymic evaluation.
Background:
Ultrasound evaluation of normal, ectopic, asymmetric, and hyperplastic thymus and also its differentiation from abnormalities are challenging in children, and few studies have addressed this issue. This study aimed to investigate the thymus sonographic changes with age.
Methods:
In this cross-sectional study, 118 healthy children were categorised into six age groups. Sonographic features of the thymus, including volume, anatomical position, symmetry, and echo-texture, were recorded.
Results:
The thymus was visible at all ages from the suprasternal view. In 77.5% of participants, the thymus gland volume in lobes was symmetrical; however, left (21.2%) and right (1.3%) predominance were also found. The most common position of the thymus was in front of the great vessels (100%) with suprasternal extension (97.5%). The mean volume of thymus was 21.3 ± 10.5 (mm). There was no significant difference in the volumes of the thymus between different age groups. The predominant echo-texture of the thymus in different age groups was hypoechoic with thin echogenic septa (liver-like) in below 2-3 years of age, the appearance of echogenic foci and hyperechoic echo-texture (liver-like with starry sky) in 2-14 years, and uniform hyperechoic echo-texture (fatty liver-like) or geographic echo-texture with coarse reticular pattern in above 14 years.
Conclusion:
In children, the thymus gland is visible in ultrasound examination in all age groups from the suprasternal view; however, the echo-texture of the normal thymus changes with age. There was no significant correlation between age and sex with total thymic volume. The specificity of these appearances has made ultrasound a problem-solving modality in children.
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