MRI enhancement scanning features and pathology of the orthotropic transplantation nude mouse model with human pancreatic cancer / 中华胰腺病杂志

ABSTRACT

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.