Elson Andrew, Paulson Eric, Bovi Joseph, Siker Malika, Schultz Chris, Laviolette Peter S
Department of Radiation Oncology, Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Froedtert Hospital East Clinics 3rd Floor, Milwaukee, WI, 53226, USA,
J Neurooncol. 2015 May;123(1):179-88. doi: 10.1007/s11060-015-1782-5. Epub 2015 Apr 17.
To investigate the association of pre-radiotherapy apparent diffusion coefficient (ADC) abnormalities with patterns of recurrence and outcomes in patients with glioblastoma multiforme (GBM).
Fifty-two patients with recurrent GBM were retrospectively evaluated. Diffusion MRI images were acquired for all patients postoperatively prior to radiotherapy. ADC images were evaluated for geographic regions of diffusion restriction (hypointensity) within the FLAIR volume. If identified, the ADC map and the T1+C MRI at the time of recurrence were registered to the original plan to determine the pattern of recurrence and the coverage of the ADC abnormality by the 60 Gy isodose line (IDL). Progression-free and overall survival was determined for patients with and without an ADC hypointensity.
An ADC hypointensity was identified in 32 (62%) of cases. The recurrence pattern in these cases was central in 27/32 (84%), marginal in 4/32 (13%) and distant in 1/32 (3%). The recurrence overlapped with the ADC hypointensity in 28 (88%) patients. The ADC hypointensity was covered by 95% of the 60 Gy IDL in all cases. Kaplan-Meier analysis revealed inferior progression free survival and overall survival in patients with an ADC hypointensity compared to those without, despite similarities between the groups in terms of age, RT dose, performance status, and extent of resection.
The presence of an ADC hypointensity on pre-radiotherapy diffusion-weighted imaging is associated with the location of tumor recurrence as demonstrated by frequent overlap in this series, and is associated with a trend toward inferior outcomes. This abnormality may reflect a high risk region of hypercellularity and warrants consideration with respect to radiotherapy planning.
探讨多形性胶质母细胞瘤（GBM）患者放疗前表观扩散系数（ADC）异常与复发模式及预后的相关性。
对52例复发性GBM患者进行回顾性评估。所有患者在放疗前术后均行扩散加权磁共振成像（MRI）检查。评估液体衰减反转恢复（FLAIR）序列图像上扩散受限（低信号）的区域。若发现扩散受限区域，则将复发时的ADC图和T1增强MRI图像与原始计划图像配准，以确定复发模式以及60 Gy等剂量线（IDL）对ADC异常区域的覆盖情况。比较有和没有ADC低信号的患者的无进展生存期和总生存期。
32例（62%）患者发现ADC低信号。这些病例的复发模式为中心型27/32（84%）、边缘型4/32（13%）和远处型1/32（3%）。28例（88%）患者的复发区域与ADC低信号区域重叠。所有病例中，95%的60 Gy IDL覆盖了ADC低信号区域。Kaplan-Meier分析显示，与无ADC低信号的患者相比，有ADC低信号的患者无进展生存期和总生存期较差，尽管两组在年龄、放疗剂量、功能状态和切除范围方面相似。
放疗前扩散加权成像上存在ADC低信号与肿瘤复发位置相关，本系列研究中二者频繁重叠即证明了这一点，且与预后较差的趋势相关。这种异常可能反映了细胞增多的高风险区域，在放疗计划时值得考虑。
