Ultrasound estimates of visceral and subcutaneous-abdominal adipose tissues in infancy

Area of Science:

• Pediatric imaging
• Body composition analysis
• Infant growth studies

Background:

• Quantifying infant internal-abdominal adiposity (IA-AT) and subcutaneous-abdominal adiposity (SCA-AT) is challenging due to impractical imaging techniques.
• Magnetic Resonance Imaging (MRI) is a reference standard but not always feasible for infant adiposity assessment.

Purpose of the Study:

• To validate ultrasound (US) measurements of visceral and subcutaneous-abdominal depths against MRI for assessing IA-AT and SCA-AT in infants.
• To analyze the association between US-derived abdominal adiposity and anthropometric measures at 3 and 12 months of age.

Main Methods:

• Twenty-two infants underwent both MRI and US for abdominal adiposity quantification.
• The Cambridge Baby Growth Study (CBGS) assessed US abdominal parameters and anthropometrics in 487 infants at 3 months and 495 at 12 months.
• Correlation analyses were performed between US and MRI measures, and between US measures and anthropometric data.

Main Results:

• US visceral and subcutaneous-abdominal depths showed significant correlations with MRI-quantified IA-AT (r=0.48) and SCA-AT (r=0.71), respectively.
• Mean US-visceral depths increased by approximately 20% between 3 and 12 months, being lower in breastfed infants.
• US measures demonstrated the ability to rank infants by IA-AT and SCA-AT, with distinct associations with birth and current skinfold thickness.

Conclusions:

• Ultrasound is a validated, practical method for assessing infant IA-AT and SCA-AT, correlating well with MRI.
• US abdominal adiposity measures provide insights into infant body composition and its regulation.
• Differential associations suggest distinct regulatory mechanisms for visceral and subcutaneous abdominal fat during infancy.