Davanian Fariba, Faeghi Fariborz, Shahzadi Sohrab, Farshifar Zahra
Department of Radiology Technology, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Department of Neurosurgery, Shohada Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Basic Clin Neurosci. 2017 Jan;8(1):13-18. doi: 10.15412/J.BCN.03080102.
The most common primary tumors of brain are gliomas and tumor grading is essential for designing proper treatment strategies. The gold standard choice to determine grade of glial tumor is biopsy which is an invasive method. The purpose of this study was to investigate the role of fiber density index (FDi) by means of diffusion tensor imaging (DTI) (as a noninvasive method) in glial tumor grading.
A group of 20 patients with histologically confirmed diagnosis of gliomas were evaluated in this study. We used a 1.5 Tesla MR system (AVANTO; Siemens, Germany) with a standard head coil for scanning. Multidirectional diffusion weighted imaging (measured in 12 noncollinear directions), and T1 weighted nonenhanced were performed for all patients. We defined two regions of interest (ROIs); 1) White matter fibers near the tumor and 2) Similar fibers in the contralateral hemisphere.
FDi of the low-grade gliomas was higher than those of high-grade gliomas, which was significant (P=0.017). FDi ratio (ratio of fiber density in vicinity of the tumor to homologous fiber tracts in the contralateral hemisphere) is higher in low-grade than high-grade tumors, (P=0.05). In addition, we performed ROC (receiver operating characteristic) curve and the area under curve (AUC) was 0.813(P=0.013).
Our findings prove significant difference in FDi near by low-grade and high-grade gliomas. Therefore, FDi values and ratios are helpful in glial tumor grading.
脑最常见的原发性肿瘤是胶质瘤，肿瘤分级对于设计恰当的治疗策略至关重要。确定胶质肿瘤分级的金标准选择是活检，这是一种侵入性方法。本研究的目的是通过扩散张量成像（DTI，一种非侵入性方法）研究纤维密度指数（FDi）在胶质肿瘤分级中的作用。
本研究评估了一组20例经组织学确诊为胶质瘤的患者。我们使用一台1.5特斯拉磁共振系统（AVANTO；德国西门子公司）及标准头部线圈进行扫描。对所有患者进行多方向扩散加权成像（在12个非共线方向测量）和T1加权非增强成像。我们定义了两个感兴趣区（ROI）：1）肿瘤附近的白质纤维；2）对侧半球的类似纤维。
低级别胶质瘤的FDi高于高级别胶质瘤，差异具有统计学意义（P = 0.017）。低级别肿瘤的FDi比率（肿瘤附近纤维密度与对侧半球同源纤维束密度之比）高于高级别肿瘤（P = 0.05）。此外，我们绘制了ROC（受试者工作特征）曲线，曲线下面积（AUC）为0.813（P = 0.013）。
我们的研究结果证明低级别和高级别胶质瘤附近的FDi存在显著差异。因此，FDi值和比率有助于胶质肿瘤分级。
