Department of Diagnostic Imaging, The Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8, Canada.
Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.
Pediatr Radiol. 2019 Aug;49(9):1201-1208. doi: 10.1007/s00247-019-04436-y. Epub 2019 Jun 15.
Concern regarding gadolinium deposition in the brain after repeated administration of intravenous gadolinium-based contrast agents has prompted evaluation of imaging alternatives.
The study purpose was to determine if magnetic resonance imaging (MRI) using conventional sequences with diffusion-weighted imaging (DWI) instead of gadolinium-based contrast-enhanced MRI is valid for local staging and guiding biopsies in osseous sarcomas.
Initial pretreatment MRI with DWI and gadolinium-based contrast-enhanced images in patients ≤ 18 years with histopathologically proven osseous sarcomas were included. Two radiologists blinded to collated demographic and clinical data, independently reviewed conventional/DWI and conventional/gadolinium-based contrast-enhanced MRI then conventional sequences alone, recording tumor size, skip lesions, necrosis, neurovascular invasion, enlarged lymph nodes and diffusion restriction. Discrepancies were resolved by a third reader. A single reader measured apparent diffusion coefficient (ADC) values in non-necrotic tumors, then correlated minimum ADC values -- with and without normalization to skeletal muscle -- with relative enhancement.
Twenty-one patients (mean age: 11.3±4.2 years, 15 [71%] females) had 14 osteosarcomas and 7 Ewing sarcomas, 50% centered in the femur. Conventional/DWI versus conventional/gadolinium-based contrast-enhanced MRI showed agreement for tumor size estimation with significant associations for necrosis (P=0.021), neurovascular involvement (P<0.001) and enlarged lymph nodes (P=0.005). Diagnostic accuracy of conventional/DWI is comparable to conventional/gadolinium-based contrast-enhanced MRI and superior to conventional sequences alone. Comparison between minimum ADC values and relative enhancement showed no correlation (P>0.05).
Significant associations of key imaging features in the initial assessment of osseous sarcomas support DWI as an alternative to gadolinium-based contrast-enhanced MRI. The lack of association between ADC values and relative enhancement suggests that they measure independent constructs, DWI dependent upon tumor cellularity and perfusion.
在反复静脉注射钆基造影剂后，人们对大脑中钆沉积的担忧促使人们对替代成像方法进行评估。
本研究旨在确定是否可以使用常规序列联合弥散加权成像（DWI）替代钆基对比增强 MRI 对骨源性肉瘤进行局部分期和引导活检。
纳入了≤18 岁经组织病理学证实的骨源性肉瘤患者的初始治疗前 MRI 检查，包括 DWI 和钆基造影增强图像。两名放射科医生在不了解收集的人口统计学和临床数据的情况下，独立地对常规/DWI 和常规/钆基造影增强 MRI 进行了评估，然后仅对常规序列进行了评估，记录肿瘤大小、跳跃病变、坏死、血管神经侵犯、淋巴结肿大和弥散受限。分歧由第三位读者解决。一名读者测量了非坏死肿瘤的表观弥散系数（ADC）值，然后将最小 ADC 值与（不与骨骼肌归一化的）最小 ADC 值与相对增强进行了相关性分析。
21 例患者（平均年龄：11.3±4.2 岁，15 例[71%]女性）中 14 例为骨肉瘤，7 例为尤文肉瘤，50%位于股骨。常规/DWI 与常规/钆基造影增强 MRI 对肿瘤大小的评估具有一致性，与坏死（P=0.021）、血管神经侵犯（P<0.001）和淋巴结肿大（P=0.005）有显著相关性。常规/DWI 的诊断准确性与常规/钆基造影增强 MRI 相当，优于单独常规序列。最小 ADC 值与相对增强之间的比较无相关性（P>0.05）。
在骨源性肉瘤的初步评估中，关键影像学特征的显著相关性支持 DWI 作为钆基造影增强 MRI 的替代方法。ADC 值与相对增强之间缺乏相关性表明它们测量的是独立的结构，DWI 依赖于肿瘤细胞密度和灌注。
