Between-slice intervals in quantification of adipose tissue and muscle in children

Area of Science:

• Pediatric imaging
• Body composition analysis
• Biomedical engineering

Background:

• Magnetic Resonance Imaging (MRI) is vital for in vivo quantification of adipose tissue (AT) and skeletal muscle (SM) in children.
• The applicability of the adult 5 cm whole-body MRI protocol in pediatric populations remains uncertain.

Purpose of the Study:

• To evaluate the appropriateness of the 5 cm whole-body MRI protocol for pediatric body composition analysis.
• To compare the accuracy of different MRI slice intervals for quantifying AT and SM in children.

Main Methods:

• Whole-body MRI with continuous 1 cm slices was performed on 73 healthy children (aged 5-17).
• Images were segmented into subcutaneous AT (SAT), visceral AT (VAT), intermuscular AT (IMAT), and SM.
• Volumes were compared between continuous acquisition and estimated protocols with 2, 3, 4, and 5 cm intervals.

Main Results:

• Percentage differences in volume measurements increased with larger slice intervals, depot size, weight, and BMI percentile.
• For group comparisons, a 5 cm interval protocol requires <5.4% more subjects for equivalent statistical power compared to a 1 cm protocol.
• Individual comparisons showed reliable detection of SM/SAT volume differences of 1-5% (0.14-0.64 L) and VAT/IMAT differences of 10-30% (0.06-0.21 L) with interval protocols.

Conclusions:

• The 5 cm MRI protocol is accurate for group comparisons of SM and SAT in children, similar to contiguous protocols.
• For individual comparisons, the 5 cm protocol is adequate for SM and SAT but less accurate for VAT and IMAT.
• Smaller slice intervals are recommended for precise individual VAT and IMAT quantification in pediatric populations.