Camargo A, Schneider T, Liu L, Pakpoor J, Kleinberg L, Yousem D M
From the Division of Neuroradiology and Russell H. Morgan Department of Radiology and Radiological Science (A.C., L.L., J.P., D.M.Y.).
the Department of Diagnostic and Interventional Neuroradiology (T.S.), University Medical Center Hamburg-Eppendorf, Hamburg Germany.
AJNR Am J Neuroradiol. 2017 Jun;38(6):1200-1205. doi: 10.3174/ajnr.A5144. Epub 2017 Apr 13.
The response rate of vestibular schwannomas to radiation therapy is variable, and there are surgical options available in the event of treatment failure. The aim of this study was to determine whether pre- and posttreatment ADC values can predict the tumor response to radiation therapy.
From a data base of 162 patients with vestibular schwannomas who underwent radiation therapy with gamma knife, CyberKnife, or fractionated stereotactic radiation therapy as the first-line therapy between January 2003 and December 2013, we found 20 patients who had pretreatment ADC values. There were 108 patients (including these 20) had serial MR images that included DWI allowing calculated ADC values from 2-132 months after radiation therapy. Two reviewers measured the mean, minimum, and maximum ADC values from elliptical ROIs that included tumor tissue only. Treatment responders were defined as those with a tumor total volume shrinkage of 20% or more after radiation therapy.
The pretreatment mean minimum ADC for nonresponders was 986.7 × 10 mm/s (range, 844-1230 × 10 mm/s) and it was 669.2 × 10 mm/s (range, 345-883 × 10 mm/s) for responders. This difference was statistically significant ( < .001). Using a minimum ADC value of 800 × 10 mm/s led to the correct classification of 18/20 patients based on pretreatment ADC values. The intraclass correlation between reviewers was 0.61. No posttreatment ADC values predicted response.
Pretreatment ADC values of vestibular schwannomas are lower in responders than nonresponders. Using a minimum ADC value of 800 × 10 mm/s correctly classified 90% of cases.
前庭神经鞘瘤对放射治疗的反应率各不相同，若治疗失败还有手术治疗方案可供选择。本研究的目的是确定治疗前和治疗后的表观扩散系数（ADC）值是否能够预测肿瘤对放射治疗的反应。
在2003年1月至2013年12月间接受伽玛刀、射波刀或分次立体定向放射治疗作为一线治疗的162例前庭神经鞘瘤患者的数据库中，我们找到了20例有治疗前ADC值的患者。共有108例患者（包括这20例）有系列磁共振成像（MR），其中包括扩散加权成像（DWI），从而能够计算出放射治疗后2至132个月的ADC值。两名阅片者测量了仅包含肿瘤组织的椭圆形感兴趣区（ROI）的平均、最小和最大ADC值。治疗反应者定义为放射治疗后肿瘤总体积缩小20%或更多的患者。
无反应者治疗前的平均最小ADC为986.7×10⁻⁶mm²/s（范围为844 - 1230×10⁻⁶mm²/s），反应者为669.2×10⁻⁶mm²/s（范围为345 - 883×10⁻⁶mm²/s）。这种差异具有统计学意义（P <.001）。根据治疗前ADC值，使用800×10⁻⁶mm²/s的最小ADC值可正确分类18/20例患者。阅片者之间的组内相关系数为0.61。治疗后的ADC值无法预测反应情况。
反应者的前庭神经鞘瘤治疗前ADC值低于无反应者。使用800×10⁻⁶mm²/s的最小ADC值可正确分类90%的病例。
