Correlation Between Rectal Cancer Multi-slice Spiral CT Perfusion Parameters And MVD,VEGF

Objective: To investigate the correlation between rectal cancer perfusion parameters and tumor microvessel density (MVD) and vascular endothelial growth factor (VEGF).Methods: 30 proctoscope and pathology confirmed rectal cancer patients were randomised selected as test group, 19 men and 11 women; age range, 28- 78 years; mean age 56.4 years. They were all adeno carcinoma. And 12 healthy volunteers were randomised selected as control group. Anisodamine was injected through vein. All patients underwent perfusion scan by Light speed pro32.The technical parameters of perfusion were as follows: a 18-gauge needle was inserted into the antebrachial vein of each patient, and 50ml of nonionic iodinated contrast medium was injected by high pressure syringe at a flow rate of 5ml/s; perfusion scanning delay was 10s. 160 sequential 5-mm-thick transverse images were obtained after 40s perfusion scanning. We used 5mm slice width in perfusion scan. Patients were asked to hold their breath during perfusion scan. All images were obtained with 400mAs, 120KV, a matrix of 512×512. All perfusion-images were sent to advantage work-station 2.0 and calculated by the CT Perfusion 2.6.8 software. The time-density curves and perfusion parameters, including blood volume (BV), blood flow (BF), mean transit time (MTT) and permeability (PS) were generated after tissue limits were defined between -200-120Hu.All rectal cancer patients in test group received operation to ectomise the tumor and we got everyone's tissue of rectal cancer. Tissue of rectal cancer and normal rectum after operation were fixed by Formaldehyde and then paraffin imbedding .Tissue sections were immuno- histochemically stained using a monoclonal antibody directed against factorⅧ-related antigen. Tissue samples were examined with an immunohistochemical stain for the expression of the VEGF. The MVD and VEGF were captured using a computerized image analysis system (Spot Cool CCD, United States) composed of a trichip RGB video-cemera (Sony ,Japan ) intalled on a light microscope (Nikon E600, Japan) .The results were measured using the Image Pro Plus 4 image analysis software (Version 4.1.0.9). and then we did following comparisons and analysis:1 the compare of CT perfusion parameters between test and control group;2 the correlation between CT perfusion parameters and MVD,VEGF of rectal cancer . All data were expressed as mean±standard error. T test was employed to compare two samples'means .Spearman analysis was used to do corralative research. P<0.05 was considered to be statistically significant. All results were caculated in a statistic software (SAS Version6.12).Results: After statistic analyzing the data of perfusion parameters and immunohistochemical result, we came to following conclusions:1 The compare of perfusion parameters between test and control group (Table 1 )Each perfusion parameter of normal rectum and rectal cancer was different.Compared with normal rectum, rectal cancer had larger BF, BV, PS, but shorter MTT.The p value was 0.0002, 0.0002, 0.0208, 0.0030, respectively.2 The correlation between perfusion parameters and VEGF, MVD of rectal cancer. (Table 2)VEGF, MVD both had positive correlation with BF, BV; negative correlation with MTT; and no correlation with PS. Conclusion: 1 CT perfusion imaging could evaluate the change of hemodynamics of rectal cancer;morbid physiology alternation generated by tumor angiogenesis could be reflected by CT perfusion imaging .2 MVD,VEGF of rectal cancer had positive correlation with BF,BV;and negative correlation with MTT.3 CT perfusion imaging could reflex tumor angiogenesis and hemodynamics,which could make the foundation for studying invasion and metastasis of rectal cancer .