The Experimental Study On MR Lymphography Combining With SPECT/CT Imaging For Sentinel Lymph Node Mapping Of Rabbit VX2 Breast Cancer

Part I: The feasibility of MR lymphography combining with SPECT/CT in detecting sentinel lymph node for rabbit VX2 breast cancer ObjectiveTo explore the feasibility of magnetic resonance lymphography(MR-LG)combining with SPECT/CT in detecting axillary and internal mammary sentinel lymph node(SLN)for rabbit VX2 breast cancer,and to analyze the number of lymph nodes compared with the sentinel lymph node biopsy(SLNB).Material and methods80 purebred female New Zealand white rabbits were randomly divided into two groups randomly,and the models of rabbit VX2 breast cancer and inflammation were respectively established.Then all successful models underwent MR-LG and SPECT/CT examinations,and the raw data was post-processed and measured.The first one or several lymph nodes along the lymph-vessel draining from the injection sites to axilla or internal mammary was/were defined as SLN(s).The results of axillary and internal mammary lymph node were recorded.Then the number of lymph nodes were analyzed compared with SLNB.Results1.In tumor group,a total of 56 animal models were established(with the success rate of 93.33%),among which 55 rabbits(98.21%,55/56)completed the MR-LG and SPECT/CT examinations,even succeeded in SLNB.In inflammation group,a total of 19 models were established(with the success rate of 95%),and all completed the examinations and succeeded in SLNB.Finally,total 74 rabbits were enrolled our study.2.A total of 168 LNs,149 ALNs,19 IMLNs,92 SLNs,77 A-SLNs,15 IM-SLNs were identified by MR-LG;A total of 173 LNs,144 ALNs,29 IMLNs,94 SLNs,74 A-SLNs,20 IM-SLNs were identified by SPECT/CT;A total of 200 LNs,164 ALNs,36 IMLNs,101 SLNs,77 A-SLNs,24 IM-SLNs were identified by MR-LG combining with SPECT/CT;A total of 258 LNs,208 ALNs,50 IMLNs,128 SLNs,94 A-SLNs,34 IM-SLNs were obtained by SLNB.3.There were significant differences between the MR-LG examination and SLNB on the numbers of LN,ALN,IMLN,SLN,A-SLN,IM-SLN mapping(all P<0.05);but there were strong correlations by these two methods(Spearman's rho correlation coefficient,r=0.718,0.678,0.752,0.695,0.348,0.705).There were significant differences between the SPECT/CT examination and SLNB on the lymph node numbers(all P<0.05),but strong correlations(r=0.713,0.621,0.765,0.689,0.186,0.765).And there were significant differences between the MR-LG examination combining with SPECT/CT and SLNB(all P < 0.05),but strong correlations(r=0.816,0.756,0.901,0.810,0.348,0.890).ConclusionMR-LG combining with SPECT/CT can effectively show the axillary and internal mammary lymph nodes for rabbit VX2 breast cancer,and has a good correlation with SLNB on the lymph node numbers.Part ?: An Experimental Study on the Influences of MR-LG combining with SPECT/CT in Detecting Internal Mammary Sentinel Lymph Node of Rabbit VX2 Breast CancerObjective To explore the feasibility of magnetic resonance lymphography(MR-LG)combining with SPECT/CT in detecting internal mammary sentinel lymph node(IM-SLN)for rabbit VX2 breast cancer,and to analyze the influences.Material and methods 80 purebred female New Zealand white rabbits were randomly divided into two groups randomly,and the models of rabbit VX2 breast cancer and inflammation were respectively established.Then all successful models underwent MR-LG and SPECT/ CT examinations,and the raw data was post-processed and measured.The results of IM-SLN and lymph-vessel were recorded,and the factors affecting IM-SLN imaging were analyzed,and then compared with the results of SLNB surgery.Results 1.Finally,total 74 rabbits were enrolled our study.On MR-LG image,the detection rate of IM-SLN was 20.27%(15/74),on SPECT/CT images,the detection rate was 24.32%(18/74),on the images of MR-LG combining with SPECT/CT,the rate was 29.73%(22/74),and in surgery of IM-SLN biopsy,the rate was 36.49%(27/74).2.The IMLN detection between tumor and inflammatory groups of MR-LG,SPECT/CT examinations,method of combine and SLNB had no statistical differences(all P>0.05).The detection number of IMLN between tumor and inflammatory groups analyzed with MR-LG combining with SPECT/CT had statistically significant difference(P<0.05).3.In MR-LG examinations of the tumor group,the experimental rabbits' weight,growth period,primary lesion size,the number and status of ASLN,as well as presence or absence of internal mammary lymph-vessels showed no statistical differences in the detection of IM-SLN(all P>0.05),while the size of ASLN(long diameter)showed significant differences(P<0.05).On SPECT/CT examinations,the above influence factors showed no statistical differences in the detection of IM-SLN(all P>0.05).4.Considering the SLNB as gold standard,the accuracy,false negative rate and false positive rate of IM-SLN detection on MR-LG were 83.78%(62/74),44.44%(12/27)and 0(0/47),which on SPECT/CT were 87.84%(65/74),25.93%(7/27)and 0(0/47),and on combining method were 93.24%(69/74),18.52%(5/27)and 0(0/47),respectively.The long diameters of IM-SLN measured by surgical specimens were greater than those of MR-LG,and the short diameters measured by surgical specimens were less than those of MR-LG,while there were no statistical differences(both P>0.05),and there was statistical difference in long and short diameter ratio(L/S)between these two groups(P=0.001).Conclusion MR-LG combining with SPECT/CT can effectively detect IM-SLN of rabbit VX2 breast cancer,but the overall imaging rate is low,and how to improve the detection rate needs further study.Part ?: An Experimental Study on the Status of Axillary Sentinel Lymph Node for Rabbit VX2 Breast Cancer using MR-LG combining with SPECT/CTObjective To explore the application value on evaluating the status of axillary sentinel lymph node(ASLN)for the rabbit VX2 breast cancer using MR-LG combining with SPECT/CT.Material and methods 80 purebred female New Zealand white rabbits were randomly divided into two groups randomly,and the models of rabbit VX2 breast cancer and inflammation were respectively established.Then all successful models underwent MR-LG and SPECT/CT examinations,and the raw data was post-processed and measured.The ASLNs were measured and recorded,and compared with SLNB and pathology.Results 1.Between SLNs and n-SLNs in the inflammatory group,there were not statistically significant differences in the short diameter,long diameter as well as short-long diameter ratio(S/L)and shape(all P>00.05).But the differences in the filling defect pattern and tumor-normal ratio(T/N)was statistically significant(?2=15.651,P=0.001 and Z=-2.232,P=0.019).2.The long diameter and short diameter of the SLNs in tumor group were greater than those of n-SLNs,and the differences were statistically significant(t=2.904,P=0.004 and t=2.379,P=0.019).Also,there were statistically significant differences between the two groups of lymph node filling defects(?2=10.437,P=0.005)and T/N ratio(Z=-3.542,P < 0.001).3.The long diameter and short diameter of axillary metastatic SLNs were bigger than those of non-metastatic SLNs(9.29 mm±2.96 mm vs.7.27 mm±1.92 mm,and 7.08 mm±2.13 mm vs.5.08 mm±1.29 mm),and the differences had statistical significance(both P < 0.05),and the shape,filling defect patterns,T/N ratio of SLNs also had significant differences(all P < 0.05).4.The area under the ROC curve(AUC)of long diameter,short diameter and T/N ratio of the SLNs were 0.733,0.815 and 0.815,respectively,of which the short diameter and T/N ratio was the largest.Conclusion MR-LG combining with SPECT/CT can be used to accurately locate SLN for breast cancer,and the short diameter,long diameter,shape as well as T/N ratio and filling defect patterns of the SLN can help to evaluate the status.