Laboratory of Physiological and Molecular Imaging of the Abdomen (IPMA) and Department of Radiology, University Paris Diderot, Sorbonne Paris Cité, INSERM UMR 773, University Hospitals Paris Nord Val de Seine, Beaujon, Assistance Publique- Hôpitaux de Paris, 100 Boulevard du Général Leclerc, 92118, Clichy Cedex, France.
Eur Radiol. 2013 Aug;23(8):2156-64. doi: 10.1007/s00330-013-2789-y. Epub 2013 Mar 2.
To compare diffusion-weighted (DW) and T2-weighted MR imaging in detecting colorectal liver metastases in a rat model, using histological examination as a reference method.
Eighteen rats had four liver injections of colon cancer cells. MR examinations at 7 T included FSE-T2-weighted imaging and SE-DW MR imaging (b = 0, 20 and 150 s/mm(2)) and were analysed by two independent readers. Histological examination was performed on 0.4-mm slices. McNemar's test was used to compare the sensitivities and the Wilcoxon matched pairs test to compare the average number of false-positives per rat.
One hundred and sixty-six liver metastases were identified on histological examination. The sensitivity in detecting liver metastases was significantly higher on DW MR than on T2-weighted images (99/166 (60 %) (reader 1) and 92/166 (55 %) (reader 2) versus 77/166 (46 %), P ≤ 0.001), without an increase in false-positives per rat (P = 0.773/P = 0.850). After stratification according to metastasis diameter, DW MR imaging had a significantly higher sensitivity than T2-weighted imaging only for metastases with a diameter (0.6-1.2 mm) similar to that of the spatial resolution of MR imaging in the current study.
This MR study with histological correlations shows the higher sensitivity of DW relative to T2-weighted imaging at 7 T for detecting liver metastases, especially small ones.
• Diffusion weighted (DW) sequences are increasingly used in magnetic resonance imaging (MRI). • DW has higher sensitivity for liver metastases than T2-weighted imaging at 7 T. • This increase in sensitivity is especially marked for small liver metastasis detection. • This higher sensitivity is confirmed in an animal model with histological correlation. • DW imaging has the potential for earlier diagnosis of small liver metastases.
在大鼠模型中，通过组织学检查作为参考方法，比较弥散加权（DW）和 T2 加权磁共振成像（MR）检测结直肠癌肝转移的能力。
18 只大鼠进行了 4 次结肠癌细胞肝内注射。在 7T 进行的 MR 检查包括 FSE-T2 加权成像和 SE-DW MR 成像（b 值分别为 0、20 和 150 s/mm²），由两位独立的读者进行分析。对 0.4mm 切片进行组织学检查。采用 McNemar 检验比较敏感性，采用 Wilcoxon 配对检验比较每只大鼠的平均假阳性数量。
在组织学检查中，共发现 166 个肝转移灶。DW MR 检测肝转移的敏感性明显高于 T2 加权成像（99/166（60%）（读者 1）和 92/166（55%）（读者 2）与 77/166（46%），P≤0.001），且每只大鼠的假阳性数量没有增加（P=0.773/P=0.850）。根据转移灶直径进行分层后，DW MR 成像在直径（0.6-1.2mm）与当前研究中 MR 成像的空间分辨率相似的转移灶检测中，其敏感性明显高于 T2 加权成像。
本项有组织学相关性的 MR 研究显示，7T 时 DW 相对于 T2 加权成像在检测肝转移方面具有更高的敏感性，尤其是对于较小的转移灶。
DW 序列在磁共振成像（MRI）中越来越多地被使用。
DW 对 7T 时的肝转移的敏感性高于 T2 加权成像。
这种敏感性的提高在小肝转移灶的检测中尤为显著。
在具有组织学相关性的动物模型中，证实了这种更高的敏感性。
DW 成像有可能更早地诊断出小的肝转移灶。
