Department of Radiology, Institute for Radiological Imaging Science, Wonkwang University School of Medicine, Shinyong-dong, Iksan, Jeonbuk, Korea.
Acad Radiol. 2011 Apr;18(4):504-11. doi: 10.1016/j.acra.2010.10.017. Epub 2011 Jan 8.
The aim of this study was to assess the feasibility of thermally cross-linked superparamagnetic iron oxide nanoparticle contrast (TCL-SPION) in magnetic resonance (MR) imaging (MRI) for the detection of lymph node metastasis in experimental model.
B16F1 human melanoma cells were subcutaneously injected into the thighs of C57BL/6 mice (n = 10). MRI was performed 21 days after tumor injection using a 4.7-T MR scanner. In vivo MRI was performed before and after the intravenous administration of TCL-SPION using T2 fast spin-echo and T2 gradient-echo pulse sequences. Then, ex vivo MR images were obtained for resected inguinal lymph nodes (n = 18) using the same pulse sequences as for in vivo imaging. On the basis of hematoxylin and eosin staining results, the lymph nodes were classified into three groups: group 1, nonmetastatic; group 2, tumor volume <50% of the resected sample; and group 3, tumor volume >50% of the resected sample. Size, signal-to-background ratio, and enhancement pattern were evaluated in each of the three groups on ex vivo images.
The findings observed on ex vivo MR images of 18 inguinal lymph nodes were compared with histopathologic findings. All nodes were classified into three groups: group 1, n = 6; group 2, n = 5; and group 3, n = 7. The sizes of the lymph nodes in group 1 were significantly different from the sizes of those in group 3 (P = .014), but there was no significant difference in lymph node sizes between groups 1 and 2 (P = .792). Signal-to-background ratios of samples in groups 2 and 3 were significantly higher than those of samples in group 1 (P = .045 and P = .007, respectively). Each group of lymph nodes showed characteristic enhancement patterns that were well correlated between the images and pathology, except for one node.
The features and extent of metastasis in the lymph nodes corresponded to those observed on TCL-SPION-enhanced MR images. TCL-SPION-enhanced MRI is useful for the detection and estimation of lymph node metastasis.
本研究旨在评估热交联超顺磁性氧化铁纳米颗粒对比剂（TCL-SPION）在磁共振成像（MRI）检测实验模型中淋巴结转移的可行性。
将 B16F1 人黑色素瘤细胞皮下注射到 C57BL/6 小鼠大腿中（n=10）。肿瘤注射后 21 天，使用 4.7-T MR 扫描仪进行 MRI。在静脉注射 TCL-SPION 前后，使用 T2 快速自旋回波和 T2 梯度回波脉冲序列进行体内 MRI。然后，使用与体内成像相同的脉冲序列对切除的腹股沟淋巴结（n=18）进行离体 MR 成像。基于苏木精-伊红染色结果，将淋巴结分为三组：第 1 组，无转移；第 2 组，肿瘤体积<切除样本的 50%；第 3 组，肿瘤体积>切除样本的 50%。在离体图像上评估每组的大小、信号背景比和增强模式。
将 18 个腹股沟淋巴结的离体 MR 图像观察结果与组织病理学发现进行比较。所有淋巴结均分为三组：第 1 组，n=6；第 2 组，n=5；第 3 组，n=7。第 1 组淋巴结的大小与第 3 组淋巴结的大小有显著差异（P=0.014），但第 1 组和第 2 组淋巴结的大小无显著差异（P=0.792）。第 2 组和第 3 组样本的信号背景比明显高于第 1 组（P=0.045 和 P=0.007）。各组淋巴结的增强模式均具有特征性，图像与病理学之间相关性良好，除一个淋巴结外。
淋巴结转移的特征和范围与 TCL-SPION 增强 MRI 图像观察到的结果一致。TCL-SPION 增强 MRI 有助于检测和评估淋巴结转移。
