Distinguishing treatment-related abnormalities (TRA) from tumor progression (TP) in glioblastoma patients is a diagnostic imaging challenge due to the identical morphology of conventional MR imaging sequences. Diffusion-weighted imaging (DWI) and its derived images of the apparent diffusion coefficient (ADC) have been suggested as diagnostic tools for this problem. The aim of this study is to determine the diagnostic accuracy of different cut-off values of the ADC to differentiate between TP and TRA. In total, 76 post-treatment glioblastoma patients with new contrast-enhancing lesions were selected. Lesions were segmented using a T1-weighted, contrast-enhanced scan. The mean ADC values of the segmentations were compared between TRA and TP groups. Diagnostic accuracy was compared by use of the area under the curve (AUC) and the derived sensitivity and specificity values from cutoff points. Although ADC values in TP (mean = 1.32 × 10−3mm2/s; SD = 0.31 × 10−3mm2/s) were significantly different compared to TRA (mean = 1.53 × 10−3mm2/s; SD = 0.28 × 10−3mm2/s) (p= 0.003), considerable overlap in their distributions exists. The AUC of ADC values to distinguish TP from TRA was 0.71, with a sensitivity and specificity of 65% and 70%, respectively, at an ADC value of 1.47 × 10−3mm2/s. These findings therefore indicate that ADC maps should not be used in discerning between TP and TRA at a certain timepoint without information on temporal evolution.
由于常规磁共振成像序列形态学表现相同，区分胶质母细胞瘤患者的治疗相关异常与肿瘤进展成为影像诊断的挑战。扩散加权成像及其衍生的表观扩散系数图像已被建议作为解决该问题的诊断工具。本研究旨在确定不同ADC截断值在鉴别肿瘤进展与治疗相关异常中的诊断准确性。共纳入76例治疗后出现新发强化病灶的胶质母细胞瘤患者。采用T1加权增强扫描对病灶进行分割，比较治疗相关异常组与肿瘤进展组分割区域的ADC均值。通过曲线下面积及截断点导出的敏感度与特异度评估诊断准确性。结果显示：肿瘤进展组ADC均值（1.32×10⁻³mm²/s；标准差0.31×10⁻³mm²/s）与治疗相关异常组（1.53×10⁻³mm²/s；标准差0.28×10⁻³mm²/s）存在显著差异（p=0.003），但两组数值分布存在明显重叠。ADC值鉴别肿瘤进展与治疗相关异常的曲线下面积为0.71，当截断值取1.47×10⁻³mm²/s时，敏感度与特异度分别为65%和70%。因此研究结果表明，在缺乏时间演变信息的情况下，不应仅凭特定时间点的ADC图对肿瘤进展与治疗相关异常进行鉴别诊断。
肿瘤(癌症)患者之家