J Korean Soc Med Ultrasound.  2001 Mar;20(1):71-75.

Sonographic Measurement of Thymic Size in Healthy Korean Neonates

• Seo HJ
• Yoon DY
• Han DH
• Han SW
• Kim HC
• Kim YM
• Choi CS
• Bae SH

Abstract

PURPOSE
To assess the variation in thymic size in healthy Korean neonates by sonography and to study the possible correlation to clinical variables.
MATERIALS and METHODS
This study was made of 112 healthy Korean neonates (94 full-term and 18 preterm), at less than a week of age. The transverse diameter of the thymus was measured in a transverse scan and the largest sagittal area was assessed in a longitudinal scan. The thymic index was defined as the product of these two values. Then, this index was compared to clinical variables, such as sex, delivery method (spontaneous delivery vs cesarian section), body weight, height, body surface area, head circumference, chest circumference, gestational age, and maternal age in both full-term and preterm groups.
RESULTS
The thymic index was 9.6 +/- 3.1 (range 3.1 -20.2) in full-term and 4.2 +/- 2.4 (range 0.9 -9.9) in preterm neonates, respectively. The thymic index was positively correlated to the body weight (R=0.550 in full-term, R=0.669 in preterm) and body surface area (R=0.549 in full-term, R=0.674 in preterm) in both full-term and preterm groups (p < 0.01). There was no statistically significant correlation to sex, delivery method, height, head circumference, chest circumference, maternal age or gestational age.
CONCLUSION
The thymic index in healthy Korean neonates as measured by sonography is significantly correlated to the body weight and body surface area of the neonate.

MeSH Terms

Body Height
Body Surface Area
Body Weight
Gestational Age
Head
Humans
Infant, Newborn*
Maternal Age
Thorax
Thymus Gland
Ultrasonography*