应用扩散加权和动态对比增强 MRI 对 Lewis 肺癌肿瘤进行放疗的早期检测。

Early detection of Lewis lung carcinoma tumor control by irradiation using diffusion-weighted and dynamic contrast-enhanced MRI.

机构信息

Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei, Taiwan.

出版信息

PLoS One. 2013 May 2;8(5):e62762. doi: 10.1371/journal.pone.0062762. Print 2013.

PURPOSE

To investigate the correlation between diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) derived parameters and radioresponsiveness of Lewis lung carcinoma (LLC) tumor.

MATERIALS AND METHODS

LLC tumor growth in C57BL/6 mouse limb was used for the experiment. The tumors were irradiated with 10 Gy×5, or 30 Gy×2 vs. sham irradiation. Fourteen tumors were subjected to DW-MRI and DCE-MRI pre-radiotherapy and weekly imaging after radiotherapy. The temporal changes in apparent diffusion coefficient (ADC) and DCE-MRI derived parameters (K(trans), k(ep), v(e), and v(p)) were correlated with tumor size, and were histologically compared with CD31 staining of resected tumors.

RESULTS

The 10 Gy×5 dose inhibited tumor growth for a week, while 30 Gy×2 controlled tumor growth for a 3-week observation period. One week after radiotherapy (week 2), irradiated tumors showed significantly higher values of ADC than untreated ones (10 Gy×5, p = 0.004; 30 Gy×2, p = 0.01). Significantly higher values of v(e) were shown earlier by 30 Gy×2 vs. sham (p = 0.01) and 10 Gy×5 vs. sham irradiation (p = 0.05). Sustained higher v(e) from 10 Gy×5 compared to sham irradiated tumors was evident at week 3 (p = 0.016) and week 4 (p = 0.046). A 13.8% early increase in ADC for 30 Gy×2 tumor group (p = 0.002) and a 16.5% increase for 10 Gy×5 group were noted (p = 0.01) vs. sham irradiation (which showed a 2.2% decrease). No differences were found for K(trans), k(ep), or v(p). Both radiotherapy groups demonstrated significant reduction in microvessel counts.

CONCLUSION

Early increase in ADC and v(e) correlated with tumor control by irradiation.

目的

研究磁共振弥散加权（DW）和动态对比增强（DCE）成像衍生参数与 Lewis 肺癌（LLC）肿瘤放疗反应之间的相关性。

材料与方法

采用 C57BL/6 小鼠肢部 LLC 肿瘤模型进行实验。肿瘤接受 10 Gy×5 或 30 Gy×2 照射或假照射。14 个肿瘤在放疗前进行 DW-MRI 和 DCE-MRI 检查，每周进行一次放疗后成像。观察 ADC 和 DCE-MRI 衍生参数（Ktrans、kep、ve 和 vp）的时间变化，并与肿瘤大小进行相关性分析，同时与切除肿瘤的 CD31 染色进行组织学比较。

结果

10 Gy×5 剂量在 1 周内抑制肿瘤生长，而 30 Gy×2 剂量在 3 周观察期内控制肿瘤生长。放疗后 1 周（第 2 周），照射肿瘤的 ADC 值明显高于未照射肿瘤（10 Gy×5，p=0.004；30 Gy×2，p=0.01）。30 Gy×2 组较假照射组（p=0.01）和 10 Gy×5 组较假照射组（p=0.05）更早出现 ve 值升高。10 Gy×5 组较假照射组在第 3 周（p=0.016）和第 4 周（p=0.046）持续表现出更高的 ve 值。30 Gy×2 组肿瘤的 ADC 值早期增加 13.8%（p=0.002），10 Gy×5 组增加 16.5%（p=0.01），而假照射组则降低 2.2%。Ktrans、kep 和 vp 没有差异。两组放疗后微血管计数均明显减少。