Caro-Domínguez Pablo, Gupta Abha A, Chavhan Govind B
Department of Diagnostic Imaging, The Hospital for Sick Children, Medical Imaging, University of Toronto, 555 University Ave., Toronto, ON, M5G 1X8, Canada.
Department of Hematology and Oncology, The Hospital for Sick Children, Toronto, ON, Canada.
Pediatr Radiol. 2018 Jan;48(1):85-93. doi: 10.1007/s00247-017-3984-9. Epub 2017 Sep 18.
There are limited data on utility of diffusion-weighted imaging (DWI) in the evaluation of pediatric liver lesions.
To determine whether qualitative and quantitative DWI can be used to differentiate benign and malignant pediatric liver lesions.
We retrospectively reviewed MRIs in children with focal liver lesions to qualitatively evaluate lesions noting diffusion restriction, T2 shine-through, increased diffusion, hypointensity on DWI and apparent diffusion coefficient (ADC) maps, and intermediate signal on both, and to measure ADC values. Pathology confirmation or a combination of clinical, laboratory and imaging features, and follow-up was used to determine final diagnosis.
We included 112 focal hepatic lesions in 89 children (median age 11.5 years, 51 female), of which 92 lesions were benign and 20 malignant. Interobserver agreement was almost perfect for both qualitative (kappa 0.8735) and quantitative (intraclass correlation coefficient [ICC] 0.96) diffusion assessment. All malignant lesions showed diffusion restriction. Most benign lesions other than abscesses were not restricted. There was significant association of qualitative restriction with malignancy and non-restriction with benignancy (Fisher exact test P<0.0001). Mean normalized ADC values of malignant lesions (1.23x10 mm/s) were lower than benign lesions (1.62x10 mm/s; Student's t-test, P<0.015). However, there was significant overlap of ADC between benign and malignant lesions, with wide range for each diagnosis. Receiver operating characteristic (ROC) analysis revealed an area under the curve (AUC) of 0.63 for predicting malignancy using an ADC cut-off value of ≤1.20x10 mm/s, yielding a sensitivity of 78% and a specificity of 54% for differentiating malignant from benign lesions.
Qualitative diffusion restriction in pediatric liver lesions is a good predictor of malignancy and can help to differentiate between benign and malignant lesions, in conjunction with conventional MR sequences. Even though malignant lesions demonstrated significantly lower ADC values than benign lesions, the use of quantitative diffusion remains limited in its utility for distinguishing them because of the significant overlap and wide ranges of ADC values.
关于扩散加权成像（DWI）在评估儿童肝脏病变中的应用数据有限。
确定定性和定量DWI是否可用于鉴别儿童肝脏良性和恶性病变。
我们回顾性分析了患有局灶性肝脏病变儿童的MRI，以定性评估病变，记录扩散受限、T2穿透效应、扩散增加、DWI及表观扩散系数（ADC）图上的低信号以及两者均为中等信号，并测量ADC值。通过病理证实或结合临床、实验室和影像学特征以及随访来确定最终诊断。
我们纳入了89名儿童（中位年龄11.5岁，51名女性）的112个局灶性肝脏病变，其中92个病变为良性，20个为恶性。观察者间在定性（kappa值0.8735）和定量（组内相关系数[ICC]0.96）扩散评估方面的一致性几乎完美。所有恶性病变均表现出扩散受限。除脓肿外，大多数良性病变无扩散受限。定性扩散受限与恶性病变显著相关，无扩散受限与良性病变显著相关（Fisher精确检验P<0.0001）。恶性病变的平均标准化ADC值（1.23×10⁻³mm²/s）低于良性病变（1.62×10⁻³mm²/s；Student t检验，P<0.015）。然而，良性和恶性病变之间的ADC值存在显著重叠，每种诊断的范围都很广。受试者操作特征（ROC）分析显示，使用≤1.20×10⁻³mm²/s的ADC临界值预测恶性病变时，曲线下面积（AUC）为0.63，鉴别恶性与良性病变的灵敏度为78%，特异度为54%。
儿童肝脏病变中的定性扩散受限是恶性病变的良好预测指标，结合传统MR序列有助于鉴别良性和恶性病变。尽管恶性病变显示出的ADC值明显低于良性病变，但由于ADC值存在显著重叠且范围较宽，定量扩散在区分它们的应用中仍然有限。
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