多参数分析渗透率和 ADC 直方图指标对小儿脑肿瘤分级的分类。
Multiparametric Analysis of Permeability and ADC Histogram Metrics for Classification of Pediatric Brain Tumors by Tumor Grade.
机构信息
From the Departments of Radiology (S.V., D.B., P.R.J., T.Y.P.)
Harvard Medical School (S.V., M.W.K., H.G.W.L., T.Y.P.), Boston, Massachusetts.
出版信息
AJNR Am J Neuroradiol. 2018 Mar;39(3):552-557. doi: 10.3174/ajnr.A5502. Epub 2018 Jan 4.
BACKGROUND AND PURPOSE
Accurate tumor grading is essential for treatment planning of pediatric brain tumors. We hypothesized that multiparametric analyses of a combination of permeability metrics and ADC histogram metrics would differentiate high- and low-grade tumors with high accuracy.
MATERIALS AND METHODS
DTI and dynamic contrast-enhanced MR imaging using T1-mapping with flip angles of 2°, 5°, 10°, and 15°, followed by a 0.1-mmol/kg body weight gadolinium-based bolus was performed on all patients in addition to standard MR imaging. Permeability data were processed and transfer constant from the blood plasma into the extracellular extravascular space, rate constant from the extracellular extravascular space back into blood plasma, extravascular extracellular volume fraction, and fractional blood plasma volume were calculated from 3D tumor volumes. Apparent diffusion coefficient histogram metrics were calculated for 3 separate tumor volumes derived from T2-FLAIR sequences, T1 contrast-enhanced sequences, and permeability maps, respectively.
RESULTS
Results from 41 patients (0.3-16.76 years of age; mean, 6.22 years) with newly diagnosed contrast-enhancing brain tumors (16 low-grade; 25 high-grade) were included in the institutional review board-approved retrospective analysis. Wilcoxon tests showed a higher transfer constant from blood plasma into extracellular extravascular space and rate constant from extracellular extravascular space back into blood plasma, and lower extracellular extravascular volume fraction ( < .001) in high-grade tumors. The mean ADCs of FLAIR and enhancing tumor volumes were significantly lower in high-grade tumors ( < .001). ROC analysis showed that a combination of extravascular volume fraction and mean ADC of FLAIR volume differentiated high- and low-grade tumors with high accuracy (area under receiver operating characteristic curve = 0.918).
CONCLUSIONS
ADC histogram metrics combined with permeability metrics differentiate low- and high-grade pediatric brain tumors with high accuracy.
背景与目的
准确的肿瘤分级对于小儿脑肿瘤的治疗计划至关重要。我们假设，通过对通透性指标和 ADC 直方图指标的组合进行多参数分析，可以高精度地区分高低级别肿瘤。
材料与方法
除了标准磁共振成像外，所有患者还进行了弥散张量成像和动态对比增强磁共振成像，使用 T1 映射翻转角为 2°、5°、10°和 15°，随后给予 0.1mmol/kg 体重的钆基造影剂。从 3D 肿瘤体积中计算了从血浆到细胞外细胞外空间的渗透率数据和转移常数、从细胞外细胞外空间回到血浆的速率常数、细胞外细胞外容积分数和血容量分数。从 T2-FLAIR 序列、T1 对比增强序列和渗透率图分别计算了 3 个独立肿瘤体积的表观扩散系数直方图指标。
结果
纳入了 41 名新诊断为对比增强脑肿瘤（低级别 16 例，高级别 25 例）的患者，这些患者的年龄为 0.3-16.76 岁，平均年龄为 6.22 岁。Wilcoxon 检验显示，高级别肿瘤的血浆到细胞外细胞外空间的转移常数和细胞外细胞外空间回到血浆的速率常数更高，细胞外细胞外容积分数更低（ <.001）。高级别肿瘤的 FLAIR 和增强肿瘤体积的平均 ADC 值明显较低（ <.001）。ROC 分析显示，血管外容积分数和 FLAIR 体积平均 ADC 值的组合可以高精度地区分高低级别肿瘤（接受者操作特征曲线下面积 = 0.918）。
结论
ADC 直方图指标与通透性指标相结合，可以高精度地区分低级别和高级别小儿脑肿瘤。
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