Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, 53792-3252, USA.
AJR Am J Roentgenol. 2012 May;198(5):1100-7. doi: 10.2214/AJR.11.7361.
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.
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.
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.
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.
内脏脂肪堆积和肝脂肪变性可能与代谢综合征相关，但目前这些并非诊断标准的一部分。我们在未增强 MDCT 上评估了这些特征。
在未增强 MDCT 上，使用专用软件（Fat Assessment Tool，EBW 版本 4.5），在脐水平测量 474 例成年人（217 例男性，257 例女性；平均年龄 58.3 岁）的皮下脂肪面积、内脏脂肪面积和内脏脂肪百分比。还记录了未增强肝脏的衰减值。代谢综合征按照国际糖尿病联合会 2005 年提出的标准定义。
男性中代谢综合征的患病率为 35.0%（76/217），女性中为 35.8%（92/257）。男性内脏脂肪面积的受试者工作特征曲线下面积（AUC）为 0.830（95%CI，0.784-0.867），女性为 0.887（0.848-0.918）（p = 0.162）。男性的皮下脂肪面积 AUC 为 0.865（0.823-0.899），女性为 0.762（0.711-0.806）（p = 0.024）。男性的内脏脂肪百分比 AUC 为 0.527（0.472-0.581），女性为 0.820（0.774-0.859）（p < 0.001）。肝脏衰减的 AUC 为 0.706（0.653-0.754）。男性的皮下脂肪面积大于 204cm²，女性的内脏脂肪面积大于 70cm²，肝脏衰减值小于 50HU 时，其敏感性和特异性分别为 80.3%和 83.7%；83.7%和 80.0%；22.0%和 96.7%。55%（11/20）无代谢综合征但有心血管事件或并发症的患者，以及 32.1%（9/28）体重指数（BMI）为 30kg/m²或以下的患者内脏脂肪面积升高。
女性中内脏脂肪堆积是代谢综合征的最佳预测指标。出乎意料的是，男性中内脏脂肪百分比是代谢综合征的一个较差预测指标，而皮下脂肪面积则是最好的预测指标。肝脏衰减值的敏感度不高，但特异性高，可用于代谢综合征的诊断。这些性别特异性差异的意义以及基于脂肪的 CT 测量与心血管风险的关系值得进一步研究。
