title: Laser beam measurement of abdominal sagittal diameter in obese children: a validation study.
abstract: OBJECTIVE
  Sagittal diameter (SAD) has been reported to correlate to visceral fat and cardiovascular risk factors. SAD is measured with the individual lying down, halfway between the lower rib margin and the iliac crest; it represents the mid-height of the abdomen. The aim of this study was to validate SAD measured using a recently-developed laser beam device (SAD(LDB) ) against SAD measured using MRI (SAD(MRI)).
  
  
  METHODS
  Of 48 obese children (25 boys, 23 girls) aged 9-11 years on the waiting list for obesity treatment, 34 agreed to a baseline measurement, which was followed by repeated measurements 6 and 12 months later in 31 and 22 children respectively. MRI was used to examine SAD(MRI) at 5 cm above (SAD(MRI,cra) ) and below (SAD(MRI,cau)) the mid plane of the L4-5 intervertebral disc.
  
  
  RESULTS
  Each of the differences SAD(LBD) - SAD(MRI, cau) and SAD(LBD) - SAD(MRI,cra) was subjected to a repeated-measurements ANOVA; the visit did not have a statistically significant effect in either case (p = 0.19 and p = 0.72, respectively). The difference SAD(LBD) - SAD(MRI, cau) was 1.50 on average (p < 0.0001; CI 1.26-1.74) while the corresponding figure for SAD(LBD) -SAD(MRI, cra) was 1.26 (p < 0.0001; CI 1.04-1.49). Regression of the difference on the mean gave slopes of -0.09 (p = 0.25) and -0.04 (p = 0.57) respectively. Prediction of SAD(MRI) from SAD(LDB) can be performed in different ways: by means of linear regression or by means of an additive correction.
  
  
  CONCLUSIONS
  Thus, this laser device can be used instead of MRI to estimate SAD by using a simple correction.
authors.affiliation: Childhood Obesity Unit, Childhood Centre Malmö, Skåne University Hospital, Malmö, Sweden. carl-erik.flodmark@skane.se
authors.forename: C E
authors.initials: CE
authors.lastname: Flodmark
authors.forename: W
authors.initials: W
authors.lastname: Shen
authors.forename: M
authors.initials: M
authors.lastname: Punyanitya
authors.forename: P
authors.initials: P
authors.lastname: Leander
authors.forename: J
authors.initials: J
authors.lastname: Lanke
authors.forename: A
authors.initials: A
authors.lastname: Pietrobelli
mesh_terms: D000005:Abdomen / Q000473:pathology*; D000704:Analysis of Variance; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000517:prevention & control; D002648:Child; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000473:pathology*; D007834:Lasers; D008279:Magnetic Resonance Imaging; D008297:Male; D056128:Obesity, Abdominal / Q000175:diagnosis*; D011627:Puberty; D015203:Reproducibility of Results; D012307:Risk Factors; D013057:Spectrum Analysis / Q000379:methods*; D013548:Sweden