CT-based body composition analysis
Overview
Quantitative measurement of skeletal muscle and adipose tissue cross-sectional areas from CT images at a standardized vertebral level, typically the third lumbar vertebra (L3). Hounsfield-unit thresholds separate skeletal muscle (−29 to 150 HU) from adipose tissue (−190 to −30 HU); areas are normalized to height squared to produce the lumbar skeletal muscle index (SMI, cm²/m²) and adipose index (ADI, cm²/m²). Patients may be dichotomized as sarcopenic (skeletal muscle depleted) using published sex-specific SMI thresholds. Whole-body lean body mass (LBM) and fat mass (FM) can be estimated from L3 cross-sections using published formulae. This method is used to evaluate body composition as a prognostic factor or treatment toxicity endpoint in oncology.
Used by
- PMID:30179230 — pre- and post-RT L3 body-composition measurements (skeletal muscle area, adipose area, SMI, ADI) performed on 215 HNSCC patients in the MD Anderson archive using Pinnacle v9.6 with HU thresholds −29 to 150 (muscle) and −190 to −30 (adipose); the dataset is the first publicly shared HNSCC RT dataset supporting body composition as a risk factor or endpoint; sarcopenia defined as SMI <52.4 cm²/m² (men) or <38.5 cm²/m² (women) PMID:30179230.
Notes
- SMI thresholds (52.4/38.5 cm²/m²) are inherited from prior cancer-cohort literature and were not re-derived for HNSCC; their applicability to head and neck populations may differ from the derivation cohorts PMID:30179230.
- Contours for body-composition measurements were reviewed by a single radiation oncologist with 5 years of post-residency experience; inter-rater reliability was not reported for this dataset PMID:30179230.
- LBM and FM are derived indirectly from L3 cross-sectional areas via published regression formulae, not from whole-body DXA or anthropometry.
Sources
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