23-Year-Old Man with Body Mass Index of 25.1.Left:UDFF—operator places crossbar at liver capsule, with sample ROI fixed 1.5 cm deep from crossbar, to ensure measurement obtained sufficiently deep to liver capsule. Overall UDFF was 3%.Right:Median MRI PDFF from three acquisitions was 3%, demonstrating agreement.
June 7, 2022 —According to ARRS’American Journal of Roentgenology(AJR), ultrasound-derived fat fraction (UDFF) is strongly associated with MRI proton-density fat fraction (PDFF) and provides high sensitivity for detectinghepatic steatosis.
俄亥俄辛辛那提儿童医院医学中心的相应作者Andrew T. Trout指出，减少测量次数足以确定总体UDFF(即三次测量中五次测量中位数的中位数)，“>5%的UDFF截止值可提供较高的AUC和灵敏度，尽管特异性较低，但用于检测MRI PDFF≥5.5%，”。
Trout and team’s cross-sectional study registered 56 overweight and obese adolescents and adults (≥16 years) who underwent investigational ultrasound (ACUSON Sequoia; deep abdominal transducer) and MRI examinations of the liver during a single visit from August to October 2020. Ultrasound examinations included three UDFF acquisitions of five measurements each. MRI examinations included three PDFF acquisitions with calculation of an overall median PDFF.
Ultimately, UDFF was positively associated with MRI PDFF (rho=0.82 [95% 0.71-0.89]; p<.001), with mean bias between methods of 4.0%. In addition, UDFF had an AUC of 0.90 (95% CI: 0.79-0.96, p<.001) for identifying an MRI PDFF ≥5.5%, with a cutoff value of >5% having 94.1% sensitivity and 63.6% specificity.
“In clinical practice,the authors of thisAJRarticle concluded, “three measurements are likely sufficient for determining UDFF.”
For more information:www.arrs.org
August 10, 2022
