Investigation of the diffusion abnormality index as a new imaging biomarker for early assessment of brain tumor response to radiation therapy
Investigation of the diffusion abnormality index as a new imaging biomarker for early assessment of brain tumor response to radiation therapy
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DOI：
10.1093/neuonc/not153
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发表时间：
2014-01-01
期刊：
影响因子：
15.9
通讯作者：
Cao, Yue
中科院分区：
文献类型：
--
作者：
Farjam, Reza;Tsien, Christina I.;Cao, Yue
扩散MRI虽然有可能成为早期评估肿瘤对治疗反应的生物标志物，但可能受到脑肿瘤内或附近水肿和坏死的混淆。本研究旨在开发和研究弥散异常指数（DAI）作为早期评估脑转移瘤放射治疗（RT）反应的新的影像学生物标志物的能力。建立患者特异性扩散异常概率函数（DAProF），以不同地解释异常的低和高表观扩散系数，反映各自的高细胞性和水肿/坏死。然后通过DAProF加权的肿瘤表观扩散系数直方图的积分来计算病灶的DAI。评价了从RT前到2 W的DAI变化，以区分反应性、稳定性和进展性肿瘤，并与相同时间间隔内的大体肿瘤体积和常规扩散指标的变化进行比较。在全脑RT治疗的病变中，DAI在预测脑转移瘤对RT的治疗后反应的所有指标中表现最好。在全脑RT硼替佐米治疗的病变中，尽管DAI是最好的预测因子，但与第一组相比，所有指标的表现都变差了。DAI用于早期评估脑转移瘤对RT反应的能力取决于治疗方案。
Diffusion MRI, although having the potential to be a biomarker for early assessment of tumor response to therapy, could be confounded by edema and necrosis in or near the brain tumors. This study aimed to develop and investigate the ability of the diffusion abnormality index (DAI) to be a new imaging biomarker for early assessment of brain metastasis response to radiation therapy (RT).Patients with either radiosensitive or radioresistant brain metastases that were treated by whole brain RT alone or combined with bortezomib as a radiation sensitizer had diffusion-weighted (DW) MRI pre-RT and 2 weeks (2W) after starting RT. A patient-specific diffusion abnormality probability function (DAProF) was created to account for abnormal low and high apparent diffusion coefficients differently, reflecting respective high cellularity and edema/necrosis. The DAI of a lesion was then calculated by the integral of DAProF-weighted tumor apparent diffusion coefficient histogram. The changes in DAI from pre-RT to 2W were evaluated for differentiating the responsive, stable, and progressive tumors and compared with the changes in gross tumor volume and conventional diffusion metrics during the same time interval.In lesions treated with whole brain RT, the DAI performed the best among all metrics in predicting the posttreatment response of brain metastases to RT. In lesions treated with whole brain RT bortezomib, although DAI was the best predictor, the performance of all metrics worsened compared with the first group.The ability of DAI for early assessment of brain metastasis response to RT depends upon treatment regimes.