Würtemberger Urs, Diebold Martin, Erny Daniel, Hosp Jonas A, Schnell Oliver, Reinacher Peter C, Rau Alexander, Kellner Elias, Reisert Marco, Urbach Horst, Demerath Theo
Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany.
Institute of Neuropathology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany.
Cancers (Basel). 2022 Feb 23;14(5):1155. doi: 10.3390/cancers14051155.
Purpose: Glioblastomas (GBM) and brain metastases are often difficult to differentiate in conventional MRI. Diffusion microstructure imaging (DMI) is a novel MR technique that allows the approximation of the distribution of the intra-axonal compartment, the extra-axonal cellular, and the compartment of interstitial/free water within the white matter. We hypothesize that alterations in the T2 hyperintense areas surrounding contrast-enhancing tumor components may be used to differentiate GBM from metastases. Methods: DMI was performed in 19 patients with glioblastomas and 17 with metastatic lesions. DMI metrics were obtained from the T2 hyperintense areas surrounding contrast-enhancing tumor components. Resected brain tissue was assessed in six patients in each group for features of an edema pattern and tumor infiltration in the perilesional interstitium. Results: Within the perimetastatic T2 hyperintensities, we observed a significant increase in free water (p < 0.001) and a decrease in both the intra-axonal (p = 0.006) and extra-axonal compartments (p = 0.024) compared to GBM. Perilesional free water fraction was discriminative regarding the presence of GBM vs. metastasis with a ROC AUC of 0.824. Histologically, features of perilesional edema were present in all assessed metastases and absent or marginal in GBM. Conclusion: Perilesional T2 hyperintensities in brain metastases and GBM differ significantly in DMI-values. The increased free water fraction in brain metastases suits the histopathologically based hypothesis of perimetastatic vasogenic edema, whereas in glioblastomas there is additional tumor infiltration.
胶质母细胞瘤（GBM）和脑转移瘤在传统磁共振成像（MRI）中常难以鉴别。扩散微结构成像（DMI）是一种新型磁共振技术，可用于估算白质内轴突内间隙、轴突外细胞间隙以及间质/自由水间隙的分布情况。我们假设，对比增强肿瘤成分周围T2高信号区域的改变可用于鉴别GBM和转移瘤。方法：对19例胶质母细胞瘤患者和17例转移瘤患者进行DMI检查。从对比增强肿瘤成分周围的T2高信号区域获取DMI指标。对每组6例患者的切除脑组织进行评估，观察其水肿模式及瘤周间质肿瘤浸润特征。结果：与GBM相比，在转移瘤周围的T2高信号区域，我们观察到自由水显著增加（p < 0.001），轴突内间隙（p = 0.006）和轴突外间隙（p = 0.024）均减少。瘤周自由水分数对GBM与转移瘤的鉴别具有判别意义，ROC曲线下面积为0.824。组织学上，所有评估的转移瘤均有瘤周水肿特征，而GBM中无或仅有少量瘤周水肿。结论：脑转移瘤和GBM的瘤周T2高信号区域在DMI值上有显著差异。脑转移瘤中自由水分数增加符合基于组织病理学的瘤周血管源性水肿假说，而胶质母细胞瘤中还存在额外的肿瘤浸润。
