Castellano Antonella, Donativi Marina, Rudà Roberta, De Nunzio Giorgio, Riva Marco, Iadanza Antonella, Bertero Luca, Rucco Matteo, Bello Lorenzo, Soffietti Riccardo, Falini Andrea
Neuroradiology Unit and CERMAC, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Via Olgettina 60, 20132, Milano, Italy.
Department of Mathematics and Physics "Ennio De Giorgi" and A.D.A.M. (Advanced Data Analysis in Medicine), University of Salento, Lecce, Italy.
Eur Radiol. 2016 May;26(5):1263-73. doi: 10.1007/s00330-015-3934-6. Epub 2015 Aug 30.
To explore the role of diffusion tensor imaging (DTI)-based histogram analysis and functional diffusion maps (fDMs) in evaluating structural changes of low-grade gliomas (LGGs) receiving temozolomide (TMZ) chemotherapy.
Twenty-one LGG patients underwent 3T-MR examinations before and after three and six cycles of dose-dense TMZ, including 3D-fluid-attenuated inversion recovery (FLAIR) sequences and DTI (b = 1000 s/mm(2), 32 directions). Mean diffusivity (MD), fractional anisotropy (FA), and tensor-decomposition DTI maps (p and q) were obtained. Histogram and fDM analyses were performed on co-registered baseline and post-chemotherapy maps. DTI changes were compared with modifications of tumour area and volume [according to Response Assessment in Neuro-Oncology (RANO) criteria], and seizure response.
After three cycles of TMZ, 20/21 patients were stable according to RANO criteria, but DTI changes were observed in all patients (Wilcoxon test, P ≤ 0.03). After six cycles, DTI changes were more pronounced (P ≤ 0.005). Seventy-five percent of patients had early seizure response with significant improvement of DTI values, maintaining stability on FLAIR. Early changes of the 25th percentiles of p and MD predicted final volume change (R(2) = 0.614 and 0.561, P < 0.0005, respectively). TMZ-related changes were located mainly at tumour borders on p and MD fDMs.
DTI-based histogram and fDM analyses are useful techniques to evaluate the early effects of TMZ chemotherapy in LGG patients.
• DTI helps to assess the efficacy of chemotherapy in low-grade gliomas. • Histogram analysis of DTI metrics quantifies structural changes in tumour tissue. • Functional diffusion maps (fDMs) spatially localize the changes of DTI metrics. • Changes in DTI histograms and fDMs precede changes in conventional MRI. • Early changes in DTI histograms and fDMs correlate with seizure response.
探讨基于扩散张量成像（DTI）的直方图分析和功能扩散图（fDM）在评估接受替莫唑胺（TMZ）化疗的低级别胶质瘤（LGG）结构变化中的作用。
21例LGG患者在密集剂量TMZ化疗三个周期和六个周期前后接受3T-MR检查，包括三维液体衰减反转恢复（FLAIR）序列和DTI（b = 1000 s/mm²，32个方向）。获得平均扩散率（MD）、各向异性分数（FA）和张量分解DTI图（p和q）。对配准后的基线和化疗后图像进行直方图和fDM分析。将DTI变化与肿瘤面积和体积的改变[根据神经肿瘤学反应评估（RANO）标准]以及癫痫发作反应进行比较。
根据RANO标准，TMZ化疗三个周期后，21例患者中有20例病情稳定，但所有患者均观察到DTI变化（Wilcoxon检验，P≤0.03）。六个周期后，DTI变化更明显（P≤0.005）。75%的患者有早期癫痫发作反应，DTI值显著改善，FLAIR图像保持稳定。p和MD第25百分位数的早期变化可预测最终体积变化（R²分别为0.614和0.561，P < 0.0005）。TMZ相关变化主要位于p和MD fDMs上的肿瘤边界处。
基于DTI的直方图和fDM分析是评估TMZ化疗对LGG患者早期疗效的有用技术。
• DTI有助于评估低级别胶质瘤化疗疗效。• DTI指标的直方图分析可量化肿瘤组织的结构变化。• 功能扩散图（fDM）在空间上定位DTI指标的变化。• DTI直方图和fDM的变化先于传统MRI的变化。• DTI直方图和fDM的早期变化与癫痫发作反应相关。
