| Objective: (1) To observe MRI manifestation of gastric carcinoma, and to evaluate the usefulness of dynamic MRI in the preoperative staging of gastric carcinoma.(2) To investigate the correlation between the dynamic MRI enhancement characteristics and tumor angiogenesis in gastric carcinoma.Materials and methods: (1) Dynamic MRI was performed on 35 patients with gastric carcinoma and 10 normal adults as control group. Dynamic MRI were prospectively assessed for manifestation of gastric carcinoma, enhanced pattern of the lesion and normal gastric wall and adjacent organs, the depth of the cancer invasion, and regional lymph node metastasis and determined staging on MR images. These MR evaluations including MR staging were correlated with the surgicopathologic findings. In addition, The pathological basis of gradual enhancement from the inner side of the lesion was discussed especially.(2) Histopathological slides of 30 patients were underwent CD34 and vascular endothelial growth factor (VEGF) immunohistochemical staining. Microvessel density(MVD) and VEGF protein expression were analysed with their relation to pathological features. The dynamic MRI characteristics including the maximum contrast enhancement ratio(CERmax) were correlatively studied with MVD and VEGF expression. Results: (1) The several layers of gastric wall were displayed on 54.3%(19/35) of cases with the moderate or plentiful water-filling method. But it could demonstrate the thickness of gastric wall, the position of the lesion and the general form of gastric carcinoma. Two patterns of manifestation on dynamic contrast-enhanced MR imagings were seen: irregularly enhancement(n=24) and delaminated enhancement(n=11). The peak time of enhancement was 53-133s, 74.3% (26/35) of which was 80-107s. The accuracy of dynamic MRI in determining T-staging was 82.9%(29/35). The sensitivityand specificity for the presence or absence of extraserosal invasion were 96.3%(26/27) and 75%(6/8), respectively. The accuracy of N-staging was 53.3%( 16/30), in which uderstaging and overstaging were noted in 36.7%(11/30) and 10%(3/30), respectively. The sensitivity and specificity for the presence or absence of lymph node metastasis were 63.6%(14/22) and 62.5%(5/8), respectively. The accuracy of M-staging was 100%(7/7).(2) In 30 cases, MVD was 13.00 to 68.25 per vision field with an average of 42.95 14.79. The low expression rate of VEGF was 30%(9/30), while the high expression rate of VEGF was 70%(21/30). MVD and VEGF expression correlated with lymph node metastasis(P < 0.05), but their relationships to the degree of differentiation and depth of invasion were not significant(P > 0.05). MVD was related to TNM-staging of gastric carcinoma(P < 0.05). The expression of VEGF between the stage of I and IV had significant differences(P < 0.05). MVD was higher in VEGF-high expression than in VEGF-low expression(P < 0.05). MVD was significantly correlated with CERmax (r=0. 556, P=0. 0014). The distribution features and shape of microvessels within gastric carcinoma were related to the enhancement characteristics such as irregularly enhancement and delaminated enhancement. The correlation between CERmax and expression of VEGF was not significant(P > 0.05).Conclusion: (1) MRI may be a promising modality for imaging gastric tumors. Dynamic MR imaging is very useful for TNM-staging gastric carcinoma.(2)The manifestations on dynamic MR imagings can reflect the distribution features and shape of microvessels within gastric carcinoma. Dynamic MR imaging may prove to be a valuble means in estimating the MVD of gastric carcinoma noninvasively, father predicting the biological behavior of gastric carcinoma, and judging prognosis. |
PDF Full Text Request