Functional MRI Study Of Soft Tissue Tumors

Part â… : Correlation study between diffusion weighted imaging and pathology of VX₂ soft-tissue tumor in rabbitsObjective To establish an experimental animal model of malignant soft tissue tumor and determine whether diffusion weighted imaging(DWI) and diffusion tensor imaging(DTI) of soft tissue tumors are feasible. Methods 20 Newzealand white rabbits were implanted with 0.2ml VX₂ tumor tissue suspension in the right proximal thighs. 40 days later, MRI and DWI/DTI were performed on these rabbits, then the images were transmitted to AW4.0 workstation. The apparent diffusion coeffient (ADC), average diffusion coefficient(ADC), fractional anisotropy(FA), isotropic(Iso), volume ratio anisotropy(VrA) of the central parenchyma area, the necrosis area, the peripheral area of the tumor, the normal muscle around the tumor and the contralateral normal muscle were calculated and analyzed. The correlation study between MRI and pathological findings was done. Results All experimental animal model of rabbit VX₂ soft tissue tumors were successfully established. The difference of FA between the central parenchyma area and the necrosis area, the peripheral area of the tumor, the adjacent and contralateral normal muscle was statistically significant (P<0.01). The ADC and VrA of the central parenchyma area of tumors had statistical difference with the necrosis area of tumors, the adjacent and contralateral normal muscle (P<0.01), but had no statistic difference with the peripheral area of tumors. The difference of ADC, FA, VrA and Iso between the adjacent and contralateral normal muscle was not statistically significant. The Iso of the normal muscle had statistic difference with the tumors. On pathological inspection, all cases of VX₂ soft tissue tumors demonstrated the central necrosis area in the lesions and undiscriminated borders with the normal muscle. Conclusion The animal model of rabbit VX₂ soft tissue tumor can be used as an experimental animal model of soft tissue tumors. DWI and DTI are beneficial to demonstrate the structure of soft tissue tumors and its border and the application value of DWI/DTI in the differentiating of benign and malignant soft tissue tumor needs further study.Part â…¡: ¹H MR spectroscopy study of VX₂ soft tissue tumors in rabbitsObjective To investigate in vivo and in vitro proton magnetic resonance spectroscopy (¹H MRS) features of normal muscle tissues and VX₂ soft tissue tumors in rabbits and to determine whether in vivo ¹H MRS of soft tissue tumors is feasible. Material and Methods 20 Newzealand white rabbits were implanted with 0.2ml VX₂ tumor tissue suspension in the right proximal thighs. We performed MRI and ¹H MRS and analyzed the ¹H MRS features of normal muscle tissue and VX₂ soft tissue tumors in all rabbits before implantation and 40 days after implantation respectively. Cho/Cr and Lipid/Cr were calculated on workstation and a student's t-test of significance was done. After the animals were sacrificed, in viro ¹H MRS of the fresh sample of normal muscle and VX₂ soft tissue tumors and its correlation with in vivo ¹H MRS findings were performed. Results: Cho, Cr and lipid peak were seen in the in vivo ¹H MRS of normal muscle and VX₂ soft tissue tumors in all rabbits. In vivo ¹H MRS in VX₂ soft tissue tumors showed prominent Cho peak and decreased Lipid peak. The average values of Cho/Cr of the VX₂ soft tissue tumors and the normal muscles were 1.7572±0.3478 and 0.6432±0.1763 and the average values of Lipid/Cr were 1.2209±0.3412 and 7.6723±2.7864 respectively. The differences of Cho/Cr and Lipid/Cr between VX₂ soft tissue tumors and normal muscles were statistically significant(P<0.01). In contrast to normal muscle, in vitro ¹H MRS revealed increased Ala, Glu, Cho, PC, Lac, mI and Gly peak and decreased Lipid and Glc peak in all cases of the VX₂ soft tissue tumor. In vivo ¹H MRS changes of Cho and Lipid in th VX₂ soft tissue tumors was consistent with in vitro ¹H MRS. Conclusion: The normal muscle and VX₂ soft tissue tumor of rabbits showed great difference in ¹H MRS. In vivo ¹H MRS findings demonstrated great consistence with that of in vitro ¹H MRS. In vivo ¹H MRS can reveal the metabolism information of the soft tissue tumors and it is feasible to diagnose the soft tissue tumors. Part III: Correlation study between diffusion weighted imaging and pathology of benign and malignant soft-tissue tumor in humanObject To explore the application value of diffusion weighted imaging(DWI) and diffusion tensor imaging(DTI) in the differetiation diagnosis between benign and malignant soft tissue tumors. Materials and Methods Of 34 cases of soft tissue tumors, there are 14 cases of benign tumors and 20 cases of malignant tumors. MRI and DWI/DTI were performed on all cases, then the images were transmitted to AW4.0 workstation. The apparent diffusion coefficient (ApDC), average diffusion coefficient(AvDC), fractional anisotropy(FA), isotropic(Iso), volume ratio anisotropy(VrA) of the central parenchyma area, the necrosis area, the peripheral area of the tumor and the normal muscle around the tumor were calculated and analyzed. The correlation study between MRI and pathology was done. Results The ADC and average ADC of the central parenchyma area and the peripheral area between the benign and malignant soft tissue tumors had significant statistical difference (P<0.01) . The difference of FA , ISO and VrA of the peripheral area between the benign and malignant soft tissue tumors was statistically significant (P<0.01) , but there was no difference in the central parenchyma area of 34 cases of tumors. On pathological inspection, 14 of 16 cases of malignant soft tissue tumors demonstrated undiscriminated borders with the normal muscle. Of 14 cases of benign soft tissue, 11 cases revealed the entire capsule around the tumors and the clear borders with the normal muscle. Conclusion DWI and DTI are beneficial to demonstrate the structure of soft tissue tumors and its border and have great application value in the differentiating diagnosis of benign and malignant soft tissue tumor.Part IV: ¹H MR spectroscopy study of benign and malignant soft tissue tumors in humanObjective To investigate the proton magnetic resonance spectroscopy (¹H MRS) features of benign and malignant soft tissue tumors in human and to explore its feasibility and application value in the differentiation diagnosis of the soft tissue tumors. Material and Methods 44 cases were included in the study and divided into three groups. There were 10 cases in nomal group, 14 cases in benign tumor group and 20 casese in malignant tumor group respectively. MRI and in vivo ¹H MRS were performed on all cases and in vitro ¹H MRS of fresh samples were studied on 20 cases of soft tissue tumors. The ¹H MRS features of all 44 cases were analyzed and the correlation study between in vivo ¹H MRS findings and that of in vitro ¹H MRS was performed. Cho/Cr and Lipid/Cr were calculated on workstation and a statistic test was done. We caculated the cell density of 30 soft tissue tumors and performed pearson correlation analysis between the cell density and Cho/Cr value. Results: Lactate peak were demonstrated in 8 cases of malignant soft tissue tumors and no case in the benign tumors and normal muscles. The ¹H MRS in malignant soft tissue tumors showed prominent increased Cho peak and decreased Lipid peak. Among 14 cases of benign soft tissue tumors, only one case revealed significant increased Cho peak and the decreased Lipid peak. The Cho/Cr value in the malignant tumor was larger than in the benign tumor and normal muscle, but the Lipid/Cr value was smaller than in the benign tumor and normal muscle. The differences of Cho/Cr value and Lipid/Cr value between malignant and benign soft tissue tumors were statistically significant(P<0.01). In contrast to benign tumor group, in vitro ¹H MRS revealed increased Cho, Lac and mI peak and decreased Lipid and Glc peak in 12 cases of the malignant tumor ,as well as increased Ala, Glu, PC and Gly peak in 8 cases of the malignant tumors. In vivo ¹H MRS changes of Cho and Lipid peak in th soft tissue tumors was consistent with in vitro ¹H MRS. The average cell density was 152/FOV in the malignant tumor group and 57/FOV in the benign tumor group. The difference of the average cell density between the two groups was statistically significant. The value of the cell density had a significant positive correlation with the Cho/Cr value in soft tissue tumors (r=0.891, P<0.001). Conclusion: The benign and malignant soft tissue tumors in human showed great difference in ¹H MRS. In vivo ¹H MRS findings demonstrated great consistence with that of in vitro ¹H MRS. In vivo ¹H MRS has high application value in the differentiation diagnosis of soft tissue tumors.