title: Visceral adiposity and hepatic steatosis at abdominal CT: association with the metabolic syndrome.
abstract: OBJECTIVE
  Visceral adiposity and hepatic steatosis may correlate with the metabolic syndrome but are not currently among the diagnostic criteria. We evaluated these features at unenhanced MDCT.
  
  
  METHODS
  Semiautomated measurements of subcutaneous fat area, visceral fat area, and visceral fat percentage were obtained at the umbilical level at unenhanced MDCT of 474 adults (217 men, 257 women; mean age, 58.3 years) using a dedicated application (Fat Assessment Tool, EBW version 4.5). Unenhanced liver attenuation was also recorded. Metabolic syndrome was defined using the criteria proposed by the International Diabetes Federation in 2005.
  
  
  RESULTS
  The prevalence of metabolic syndrome was 35.0% (76/217) among men and 35.8% (92/257) among women. The area under the receiver operating characteristic curve (AUC) for visceral fat area was 0.830 (95% CI, 0.784-0.867) in men and 0.887 (0.848-0.918) in women (p = 0.162). The AUC for subcutaneous fat area was 0.865 (0.823-0.899) in men and 0.762 (0.711-0.806) in women (p = 0.024). The AUC for visceral fat percentage was 0.527 (0.472-0.581) in men and 0.820 (0.774-0.859) in women (p < 0.001). The AUC for liver attenuation was 0.706 (0.653-0.754). Thresholds of subcutaneous fat area greater than 204 cm(2) in men, visceral fat area greater than 70 cm(2) in women, and liver attenuation less than 50 HU yielded a sensitivity and specificity of 80.3% and 83.7%; 83.7% and 80.0%; and 22.0% and 96.7%, respectively. Visceral fat area was elevated in 55% of patients without metabolic syndrome (11/20) but with a documented cardiovascular event or complication and in 32.1% of patients with a body mass index of 30 kg/m(2) or less.
  
  
  CONCLUSIONS
  Accumulation of visceral fat was the best predictor for metabolic syndrome in women. Unexpectedly, the percentage of visceral fat was a poor predictor for metabolic syndrome in men and subcutaneous fat area was best. Decreased liver attenuation was insensitive but was highly specific for metabolic syndrome. The implications of these sex-specific differences and the relationship of fat-based CT measures to cardiovascular risk warrant further investigation.
authors.affiliation: Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, 53792-3252, USA. ppickhardt2@uwhealth.org
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Pickhardt
authors.forename: Young
authors.initials: Y
authors.lastname: Jee
authors.forename: Stacy D
authors.initials: SD
authors.lastname: O'Connor
authors.forename: Alejandro Muñoz
authors.initials: AM
authors.lastname: del Rio
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D016009:Chi-Square Distribution; D005234:Fatty Liver / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000000981:diagnostic imaging*; D008297:Male; D024821:Metabolic Syndrome / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008875:Middle Aged; D015995:Prevalence; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*