title: Measurement of waist circumference for retrospective studies - prospective validation of use of CT images to assess abdominal circumference.
abstract: BACKGROUND
  To validate the use of supine position and CT images for assessing abdominal circumference (AC).
  
  
  METHODS
  A prospective study in consecutive patients undergoing scheduled abdominal CT at our center between 17 and 25 September 2012. AC was measured four times: Measurements 1 and 2 were sequentially done by the same trained nurse before abdominal CT just above the iliac crest, while measurements 3 and 4 were done on the last abdominal CT slice not showing the iliac bone. Student's t tests and Q-Q and Bland-Altman plots were used for statistical analysis.
  
  
  RESULTS
  A total of 102 patients were recruited. Mean age, 60 (35-78) years. Mean BMI, 25 (18-39) kg/m(2). Mean AC, 93.2 (73-135) cm. No significant differences were found between the four ACs measured (Student's t test, P=0.83). Q-Q and Bland-Altman plots showed good overlapping for the low and central values (73-110 cm) with a greater scatter for extremely high values. For the ellipse estimation, R(2) was 0.987 with a mean error of 0.4 cm and a stretch dispersion between 1.1 and -0.3 cm.
  
  
  CONCLUSIONS
  Supine (either measured or estimated on CT images by free hand elliptical ROI or ellipse formula) and standing measurements appear to be equivalent for abdominal circumferences <110 cm.
authors.affiliation: Urology Department, Hospital Clínic Barcelona, Spain; Urology Department, Fundación Sanitaria Hospital de Mollet, Barcelona, Spain. Electronic address: alexciudin@yahoo.com.
authors.forename: Alexandru
authors.initials: A
authors.lastname: Ciudin
authors.affiliation: Radiology Department, Hospital Clínic Barcelona, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Salvador
authors.affiliation: Radiology Department, Hospital Clínic Barcelona, Spain.
authors.forename: Alex
authors.initials: A
authors.lastname: Budoy
authors.affiliation: Endocrinology Department, Hospital Vall d'Hebron Barcelona, Spain.
authors.forename: Andreea
authors.initials: A
authors.lastname: Ciudin
authors.affiliation: Radiology Department, Hospital Parc Tauli Sabadell, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Spinu
authors.affiliation: Urology Department, Hospital Clínic Barcelona, Spain.
authors.forename: Mihai Gabriel
authors.initials: MG
authors.lastname: Diaconu
authors.affiliation: Surgery and Urology Department, Hospital "Sf Pantelimon" Bucharest, Romania.
authors.forename: Vlad
authors.initials: V
authors.lastname: Constantin
authors.affiliation: Urology Department, Hospital Clínic Barcelona, Spain; Urology Department, Fundación Sanitaria Hospital de Mollet, Barcelona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Sánchez
authors.affiliation: Radiology Department, Hospital Clínic Barcelona, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Nicolau
authors.affiliation: Urology Department, Hospital Clínic Barcelona, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Alcaraz
mesh_terms: D000328:Adult; D000368:Aged; D001837:Body Weights and Measures / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055105:Waist Circumference
keywords: Abdominal CT; Abdominal circumference; Decúbito supino; Ellipse perimeter; Perímetro abdominal; Perímetro elipse; Supine position; Tomografía axial computarizada abdominal