人胰腺癌原位移植模型MRI增强扫描特征及病理对照研究

目的 探讨人胰腺癌原位移植瘤模型的MRI影像学表现及其病理基础.方法 应用3.0T磁共振成像仪及临床型乳腺线圈对30只胰腺癌裸鼠原位模型行冠状位及横断位TSE-T1 WI/T2 WI平扫,经腹腔注射钆喷酸葡胺(Gd-DTPA)行连续动态增强扫描,测量平扫和增强扫描各时相肿瘤信号强度,计算强化率,分析MR图像特征并与病理对照.结果 30只裸鼠荷瘤接种成功率为100%,组织学检查符合胰腺低分化腺癌.与邻近组织信号相比,90%(27/30)肿瘤T1 WI呈均匀稍低信号,10%(3/30)信号欠均匀;80%(24/30)肿瘤T2 WI呈不均匀高信号、内见斑片状更高或等信号区,20%(6/30)呈均匀等高信号.平扫肿瘤信号强度为228.35±11.71,增强扫描后1.5、3、6,9、12 min的肿瘤信号强度分别为258.20±11.17、301.75±17.09、358.65±25.13、480.05±19.01、558.35±40.49,均明显高于平扫(P值均<0.01);各时相强化率分别为0.13±0.04、0.35±0.11、0.56±0.10、1.10±0.10、1.45±0.18,各时相间差异均有统计学意义(P值均<0.01).MR强化明显区为供血丰富的肿瘤生长活跃区域,中央无强化区为坏死组织和(或)肿瘤细胞致密且毛细血管较少区域.结论 经腹腔注射对比剂后可获得清晰的移植瘤MRI图像,与病理检查结果具有很好的一致性.

MRI enhancement scanning features and pathology of the orthotropic transplantation nude mouse model with human pancreatic cancer

Objective To investigate the MRI imaging features, and pathologic basis of the orthotropic transplantation nude mouse model with human pancreatic cancer. Methods Adopting Siemens Magnetom Trio Tim 3.0 Tesla superconductive MRI and breast coil was used to examine 30 orthotropic transplantation nude mouse models of the human pancreatic cancer, these mouse were sampled to acquire TSE-T1 -weighted and T2-weighted transverse axial images. Intraperitoneal injection of Gd DTP A was used to perform continuous dynamic enhancement scanning. Signal intensities of tumors were measured in plain scanning and each phase' s enhancement scanning images, respectively. Intensification rates of tumors were calculated. Pathologic examination of tumors was performed to be compared with the findings of MRI scanning. Results The successful rate of inoculation of 30 nude mice was 100%. The histological findings were comparable with poorly differentiated adenocarcinoma. Compared with signal of adjacent tissues, the MRI findings of the tumors were uniformly slightly hypointensity (90% , 27/30) , or unevenly (10% , 3/30) on TSE-T1WI; uniformly (20% , 6/30) or unevenly (80% , 24/30) hyperintensity with equal or more hyper signal spots on TSE-T2WI. Signal intensities on plain scanning was 228.35 ±11.71, and 1.5,3,6,9, 12 min after enhancement scanning, thesignal intensities were 258.20 ± 11.17, 301.75 ± 17.09, 358.65 ±25.13, 480.05 ± 19.01, 558.35 ± 40.49, which were significantly higher than those in plain scanning (P <0.01). The intensification rate of every phase was 0.13 ±0.04, 0.35 ±0.11, 0.56 ±0.10, 1.10 ±0.10, 1.45 ±0.18, and the difference among these phases was statistically significant (P <0.01). The significantly intensified area was the area where the tumor cells grew actively with rich capillaries; the central area without intensification was the area of necrotic tissue and/or densely packed tumor cells and few capillaries. Conclusions High resolution MRI imaging of implanted tumors can be obtained by intraperitoneal injection of contrast, and it is consistent with pathologic examinations.