Body composition estimation from selected slices: equations computed from a new semi-automatic thresholding method developed on whole-body CT scans

Abstract

BackgroundEstimating volumes and masses of total body components is important for the study and treatment monitoring of nutrition and nutrition-related disorders, cancer, joint replacement, energy-expenditure and exercise physiology. While several equations have been offered for estimating total body components from MRI slices, no reliable and tested method exists for CT scans. For the first time, body composition data was derived from 41 high-resolution whole-body CT scans. From these data, we defined equations for estimating volumes and masses of total body AT and LT from corresponding tissue areas measured in selected CT scan slices.MethodsWe present a new semi-automatic approach to defining the density cutoff between adipose tissue (AT) and lean tissue (LT) in such material. An intra-class correlation coefficient (ICC) was used to validate the method. The equations for estimating the whole-body composition volume and mass from areas measured in selected slices were modeled with ordinary least squares (OLS) linear regressions and support vector machine regression (SVMR).Results and DiscussionThe best predictive equation for total body AT volume was based on the AT area of a single slice located between the 4th and 5th lumbar vertebrae (L4-L5) and produced lower prediction errors (|PE| = 1.86 liters, %PE = 8.77) than previous equations also based on CT scans. The LT area of the mid-thigh provided the lowest prediction errors (|PE| = 2.52 liters, %PE = 7.08) for estimating whole-body LT volume. We also present equations to predict total body AT and LT masses from a slice located at L4-L5 that resulted in reduced error compared with the previously published equations based on CT scans. The multislice SVMR predictor gave the theoretical upper limit for prediction precision of volumes and cross-validated the results.

Sex‐specific functional adaptation of the femoral diaphysis to body composition

“…It has been shown that CT scan slices located at the waist level are the most efficient way to estimate total body components mass or volumes when those cannot be directly estimated with whole‐body based techniques (Kvist, Chowdhury, Grangard, Tylen, & Sjöström, ; Lacoste Jeanson et al, ; Lemieux, Lesage, & Bergeron, ; Mourtzakis et al, ). We estimated total body FM and FFM, and calculated the resulting body fat percentage (BF%) from these data, using a new set of regression equations from a slice located between the 4th and 5th lumbar vertebrae (Lacoste Jeanson et al, ). The cross‐validation test for those equations showed absolute prediction errors not greater than ± 3.67 kg for FFM, and 1.71 kg for FM by individual (Lacoste Jeanson et al, ).…”

“…We estimated total body FM and FFM, and calculated the resulting body fat percentage (BF%) from these data, using a new set of regression equations from a slice located between the 4th and 5th lumbar vertebrae (Lacoste Jeanson et al, ). The cross‐validation test for those equations showed absolute prediction errors not greater than ± 3.67 kg for FFM, and 1.71 kg for FM by individual (Lacoste Jeanson et al, ).…”

Percutaneous CT‐Guided Cryovagotomy in Patients with Class I or Class II Obesity: A Pilot Trial

“…Body composition was measured using CT during the procedure and at terminal follow‐up, according to established methods . Specifically, from each procedure image set, an axial section that crossed the L1 center was identified.…”

Diaphysator: An online application for the exhaustive cartography and user‐friendly statistical analysis of long bone diaphyses

“…To test the efficiency of both the Extractor and Diaphysator, we used a sample of whole‐body CT scans performed on cadavers at the University of Copenhagen, Department of Forensic Medicine, Unit of Forensic Anthropology in Copenhagen, Denmark (Lacoste Jeanson, Dupej, et al, ; Lacoste Jeanson, Santos, et al, ; Villa et al, ). The bodies have not been positioned in a standardized fashion prior to scanning.…”

“…The sample consists of 36 males and 42 females. Full descriptive data of the sample can be found elsewhere (Lacoste Jeanson, Dupej, et al, ; Lacoste Jeanson, Santos, et al, ; Villa et al, ). The full data, along with those of the tibial diaphysis, are publicly available on Zenodo (Lacoste Jeanson, ) or by clicking the “Help” button in the Diaphysator user interface.…”