Preparation And MRI Research Of Postsurgery Scar Tissue And Recurrent Tumor Model

Objective:To prepare the postoperative scar models and research it's pathology findings.Methods:Postoperative scar models were made in the hind thigh of 9 New Zealand white rabbits. After anesthetize with Su Mian XinⅡby intramuscular injection, In the sterile environment, we blunt dissected and partly mutilate the hind thigh muscles. Then we folded and packed a asepsis saline sooked gauze of 3cm2 between the muscle bellies. The gentamicin sulfate was used to prevent infection after operation. Two weeks later, the gauze was surgically removed in aseptic conditions. After 3 weeks of observation, we took the scar tissue to do pathology examination and make microphotograph under the microscope.Results:All the 9 postoperative scar models were successful. The size of the scar tissue was about 1.3-2.6cm, The main color was white. Under the microscope, a lot fibroblasts were hyperplasia and collagen fibrils deposited in the scar tissue. In the scar, there was some small vessels remnant and some phlegmasia cells infiltrated. Conclusion:To blunt dissected the muscles and packed gauze between the muscle bellies is a good method to make the postoperative scar models. The pathology appearances of the models were similar to the hyperplastic scar. Objective:To establish experimental animal models of postoperative scar tissue and determine whether MRI and pathology of postoperative scar are associated. Materialand Methods:Postoperative scar models were made in the hind thigh of 20 New Zealand white rabbits. In the sterile environment, we blunt dissected and partly mutilate the post thigh muscles after anesthetize. Then we folded and packed a asepsis saline sooked gauze of 3cm2 between the muscle bellies. The gentamicin sulfate was used to prevent infection after operation. Two weeks later, the gauze was surgically removed in aseptic conditions. After 3 weeks of observation, we used Ge Excite 1.5T superconducting MR device to made plain MRI scanning,DWI and DCE-MRI. We took the scar tissue to do pathology examination after scanning. Results:All the 20 postoperative scar models were successful. Under the microscope, a lot fibroblasts were hyperplasia and collagen fibrils deposited in the scar tissue. In the scar, there was some small vessels remnant. The scar tissue appeared middling T1 and long T2 signal in the plain scanning. On DWI, the scar tissue appeared high signal. On ADC imaging, the scar tissue appeared middle or slightly low signal. When we used b=200s/mm2, the difference of ADC were not statistically significant between the scar and muscle. But at b=400s/mm2 and b=600s/mm2, the difference of ADC were statistically significant between the scar and muscle. On DCE-MRI, the time-signal intensity curve was ascended slowly in 12 cases. In the other 8 cases, the time-signal intensity curve was keeping a relative high level after ascended the maximum intensity. The difference of the time-signal intensity curve was statistically significant between the scar and muscle. Conclusion:The.findings of post operative scar tissue were similar to some benign lesions on MRI. The appearances of post operative scar tissue on MRI were the reflection of their pathology. Objective:Our purpose is to establish experimental animal models of postoperative scar and recurrent tumor, and to investigate in vivo proton magnetic resonance spectroscopy (1H MRS) features of the models. Material and Methods:We used 20 New Zealand white rabbits to establish the models. In the sterile environment, we blunt dissected and partly mutilate the post right thigh muscles of the rabbits after anesthetize. Then we folded and packed two asepsis saline sooked gauzes of 3cm2 between the muscle bellies. At the same time, we implanted with 1ml VX2 tumor tissue suspension in the left proximal thighs. The gentamicin sulfate was used to prevent infection after operation. Two weeks later, the gauzes and the tumor was surgically removed in aseptic conditions. But the peplos of the tumor was remained partly. After 3 weeks of observation, We performed MRI and 1H MRS and analyzed the 1H MRS features of postoperative scar tissue and recurrent VX2 tumors in all rabbits. Results:Twenty models were all successful. A lot fibroblasts were hyperplasia and collagen fibrils deposited in the scar tissue. In the scar, there was some small vessels remnant. In the recurrent tumors, the tumor cells were distributed diffusion or like nests. The nuclear of the recurrent tumor was obviously heteromorphy. Among the interstitial substances of the recurrent tumor, there was a lot of immature vascular hyperplasia. Cho, Cr and lipid peak were seen in the in vivo 1H MRS of normal muscle. The Lip peak was the highest, the Cr was higher, and the Cho was low. The 1H MRS of 17 cases was successfully acquired in the 20 postoperative scar models. Five had the very low Cho and Cr peak of the 17 cases. There were no Cho and Cr in the other 12 cases. The Lip and the Cho peak of all the recurrent tumors were obviously high. But the Cr was low. The Lip was lower than the muscle and the Cho was higher than the muscle. Conclusion:The postoperative scar and recurrent VX2 tumor of rabbits showed great difference in 1H MRS. In vivo 1H MRS may reveal the difference of metabolism information in the postoperative scar and recurrent tumor. Maybe 1H MRS can be used to the differential diagnosis between the postoperative scar tissue and the recurrent tumor. Objective:To study the DCE-MRI findings of the postoperative scar tissue and the recurrent tumor models. Correlate the DCE-MRI findings and the pathology findings of the postoperative scar tissue and recurrent tumor to analysis their associativity. To investigate the differentiation diagnosis value of DCE-MRI in postoperative scar and recurrent tumor.Material and Methods:20 New Zealand white rabbits were used to establish the models. In the sterile environment, we blunt dissected and partly mutilate the post right thigh muscles of the rabbits after anesthetize. Then we folded and packed two asepsis saline sooked gauzes of 3cm2 between the muscle bellies. At the same time, we implanted with lml VX2 tumor tissue suspension in the left proximal thighs. The gentamicin sulfate was used to prevent infection after operation. Two weeks later, the gauzes and the tumor was surgically removed in aseptic conditions. But the capsule of the tumor was remained partly. After 3 weeks of observation, We performed DCE-MRI used 3D-FSPGR series and analyzed the DCE-MRI features of postoperative scar tissue and recurrent VX2 tumors in all rabbits. We used GD-DTPA as the contrast media. To compare the time-signal intensity curve and the Emax, Es value between the postoperative scar tissue and the recurrent tumor.Results:Twenty models were all successful. A lot fibroblasts were hyperplasia and collagen fibrils deposited in the scar tissue. In the scar, there was some small vessels remnant. In the recurrent tumors, the tumor cells were distributed diffusion or like nests. The nuclear of the recurrent tumor was obviously heteromorphy. Among the interstitial substances of the recurrent, there was a lot of immature vascular hyperplasia. The time-intensity curve of scar tissue in 11 rabbits ascended slowly but descended not obvious. In 9 rabbits, The time-signal intensity curve of scar tissue ascended quickly and keep a relative high level after reaching the peak value. The time-signal ntensity curve of recurrent tumor ascended suddenly and descended slowly after reaching the peak value in 13 rabbits. In 7 rabbits, The time-signal intensity curve of recurrent tumor ascended and descended quickly. The Emax and Es value of postoperative scar respectively were 57.63±15.02 and 0.62±0.35. The Emax and Es value of recurrent tumor respectively were 125.26±27.61 and 1.38±0.47.Their difference was statistically significant (p<0.05). Conclusion:The difference of the maximum percentage of enhancement (Emax) and enhancement slope(Es) between postoperative scar tissue and recurrent tumor are all significant. The difference is the reflection of their pathology. MR perfusion weighted imaging may be efficacious method to distinguish postoperative scar tissue and recurrence tumor.