Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
University of Cincinnati College of Medicine, 3230 Eden Ave., Cincinnati, OH, 45267, USA.
Pediatr Radiol. 2022 Jun;52(7):1306-1313. doi: 10.1007/s00247-022-05313-x. Epub 2022 Mar 1.
Non-alcoholic fatty liver disease (NAFLD) is increasing in prevalence and is the most common cause of pediatric chronic liver disease. Objective US-based measures of hepatic steatosis are an unmet clinical need.
To evaluate the diagnostic performance of quantitative measurement of liver echogenicity (hepatorenal index, or HRI) for hepatic steatosis in a pediatric cohort.
We identified pediatric patients (≤18 years old) who underwent both clinically indicated abdominal US and MRI with liver proton-density fat fraction (PDFF) within the 3-month period during the timeframe of July 2015-April 2020 (n=69). Using ImageJ, we drew small circular regions of interest (ROIs) and large freehand ROIs in the liver and right kidney on single longitudinal and transverse images to measure echogenicity (arbitrary units). We calculated four HRIs (liver-to-kidney ratio) as well as liver histogram features. Five pediatric radiologists independently reported the qualitative presence/absence of hepatic steatosis. We used Pearson correlation (r) to assess associations and receiver operating characteristic (ROC) curve analyses to evaluate diagnostic performance. Multivariable logistic regression was used to further assess relationships.
Mean patient age was 11.6 (standard deviation [SD] 4.7, range 0.3-18) years; 27/69 (39.1%) were female. Mean PDFF was 12.5% (SD 13.1%, range 1-48%); 34/69 (49.3%) patients were classified as having hepatic steatosis by MRI (PDFF ≥6%). There were significant, positive correlations between all four US HRI methods and PDFF (r=0.51-0.61); longitudinal freehand ROIs exhibited the strongest correlation (r=0.61; P<0.0001). Longitudinal freehand ROI HRI had moderate diagnostic performance for the binary presence of steatosis (area under the curve [AUC]=0.80, P<0.0001), with an optimal cut-off value >1.75 (sensitivity=70.6%, specificity=77.1%). Radiologists' sensitivity for detecting hepatic steatosis ranged from 79.4% to 97.1%, and specificity ranged from 91.2% to 100%. Significant multivariable predictors of PDFF ≥6% included HRI (P=0.002; odds ratio [OR]=34.2), body mass index (BMI) percentile (P=0.005; OR=1.06), and liver gray-scale echogenicity standard deviation (P=0.02; OR=0.79) (receiver operating characteristic AUC = 0.92).
Quantitative US HRI has moderate diagnostic performance for detecting liver fat in children and positively correlates with MRI PDFF. Incorporation of BMI-percentile and gray-scale echogenicity standard deviation improved diagnostic performance.
非酒精性脂肪性肝病（NAFLD）的患病率正在上升，是儿童慢性肝病的最常见原因。基于美国的肝脂肪变性客观测量方法是一种未满足的临床需求。
评估在儿科队列中定量测量肝回声（肝肾指数，HRI）对肝脂肪变性的诊断性能。
我们在 2015 年 7 月至 2020 年 4 月期间的 3 个月内，确定了同时接受临床指征腹部超声和 MRI 检查且肝质子密度脂肪分数（PDFF）的儿科患者（≤18 岁）（n=69）。使用 ImageJ，我们在单个纵向和横向图像上对肝脏和右肾的小圆形感兴趣区（ROI）和大徒手 ROI 进行测量，以测量回声（任意单位）。我们计算了四种 HRI（肝/肾比）以及肝直方图特征。五名儿科放射科医生独立报告了肝脂肪变性的定性存在/不存在。我们使用 Pearson 相关（r）评估相关性，并使用接收器操作特征（ROC）曲线分析评估诊断性能。多变量逻辑回归用于进一步评估相关性。
患者平均年龄为 11.6 岁（标准差[SD] 4.7，范围 0.3-18）；27/69（39.1%）为女性。平均 PDFF 为 12.5%（SD 13.1%，范围 1-48%）；34/69（49.3%）的患者通过 MRI（PDFF≥6%）被归类为患有肝脂肪变性。所有四种 US HRI 方法与 PDFF 之间均存在显著正相关（r=0.51-0.61）；纵向徒手 ROI 相关性最强（r=0.61；P<0.0001）。纵向徒手 ROI HRI 对脂肪变性的二进制存在具有中等的诊断性能（曲线下面积[AUC]=0.80，P<0.0001），最佳截断值>1.75（灵敏度=70.6%，特异性=77.1%）。放射科医生检测肝脂肪变性的灵敏度范围为 79.4%至 97.1%，特异性范围为 91.2%至 100%。PDFF≥6%的显著多变量预测因素包括 HRI（P=0.002；优势比[OR]=34.2）、体重指数（BMI）百分位数（P=0.005；OR=1.06）和肝灰阶回声标准差（P=0.02；OR=0.79）（ROC 曲线 AUC=0.92）。
定量 US HRI 对儿童肝脏脂肪的检测具有中等的诊断性能，与 MRI PDFF 呈正相关。BMI 百分位数和灰阶回声标准差的纳入提高了诊断性能。
