| Part ?THE VALUE OF CEMRI IN EVALUATION OF THE TREATMENT OF RENAL CELL CARCINOMA AFTER MICROWAVE ABLATIONObjectiveTo investigate the value of contrast-enhanced magnetic resonance imaging(CEMRI)in evaluating the curative effect of renal cell carcinoma(RCC)after microwave ablation(MWA).MethodsThe data of 52 patients with RCC treated by MWA and followed up by MRI from June 2012 to May 2019 were collected as study objects,including 36 males and 16 females,at the age of 34-82 years with an average age of 57.Among them,there were 3 cases of an isolated kidney,4 cases of multiple cysts in both kidneys,5 cases of renal insufficiency,2 cases of malignant tumor complicated with other organs,and 8 cases of cardiopulmonary dysfunction or infirmity.There were 52 lesions,28 in the left kidney and 24 in the right one,with a maximum diameter of 1.1?3.9cm and an average diameter of 2.3cm.All cases underwent puncture biopsy before operation.Pathology confirmed renal cell carcinoma.Conventional MRI scans and CEMRI were performed on these cases within 1 week before MWA and 1 day,1 month,3 months and 6 months after MWA.The variation characteristics of conventional MRI and CEMRI image signals in the follow-up time before and after MWA were observed,in order to summarize their wariation laws.Chi-square test was applied to comparing the dynamic changes of tumor contrast-enhanced scanning after MWA for RCC.ResultsAccording to the follow-up results as a standard,after 52 cases of RCC were treated by MWA,49 cases were completely ablated,1 case remained,and 2 cases found local tumor progression 12 months and 40 months after operation respectively.ON the first day after complete ablation,all MWA areas typically exhibited hyperintensity on T1WI and hypointensity on T2WI with fat suppression.As time went on,T1WI signal intensity tended to decrease and T2WI signal rose,unevenly,showing mixed signal 3 months and 6 months later.The lesions completely ablated showed annular enhancement(40/48)one day after MWA.At 1 month,the annular enhanced lesions(20/36)decreased,and some lesions showed no enhancement(16/36);There was no enhancement after 3 and 6 months(22/27,23/30).Except that there was no difference at 3 and 6 months after the operation,the difference between the other groups was statistically significant(P<0.015).The 1 case of residual lesion and 2 cases of recurrent lesion had irregular edge of MWA region,nodular T2WI with fat suppression image with slightly higher signal,T1WI with equal signal and obvious enhancement in CEMRI dermomedullary phase.ConclusionMRI manifestations of renal cell carcinoma in different time periods after MWA treatment have certain characteristics.Due to the different dynamic enhancement manifestations of various tissues,CEMRI can effectively differentiate the completely necrotic region,active tumor tissue and normal renal tissues,accurately evaluate the curative effect,and provide an objective basis for clinical follow-up treatmentPart ?THE VALUE OF DWI IN EVALUATION OF THE TREATMENT OF RENAL CELL CARCINOMA AFTER MICROWAVE ABLATIONObjectiveTo investigate the value of magnetic resonance diffusion-weighted imaging(MR-DWI)in evaluating the curative effect of renal cell carcinoma(RCC)after microwave ablation(MWA).MethodsThe data of 52 patients with RCC treated by MWA and followed up by MRI from June 2012 to May 2019 were collected as study objects,including 36 males and 16 females,at the age of 34-82 years with an average age of 57.Among them,there were 3 cases of an isolated kidney,4 cases of multiple cysts in both kidneys,5 cases of renal insufficiency,2 cases of malignant tumor complicated with other organs,and 8 cases of cardiopulmonary dysfunction or infirmity.There were 52 lesions,28 in the left kidney and 24 in the right one,with a maximum diameter of 1.1?3.9cm and an average diameter of 2.3cm.All cases underwent puncture biopsy before operation.Pathology confirmed renal cell carcinoma.Conventional MRI scans,diffusion weighted imaging(DWI)and contrast-enhanced MRI on these cases within 1 week before MWA and 1 day,1 month,3 months and 6 months after MWA.Variations of DWI signal changes and ADC value changes were observed before and after MWA.ResultsAccording to the follow-up results as a standard,after 52 cases of RCC were treated by MWA,49 cases were completely ablated,1 case remained,and 2 cases found local tumor progression 12 months and 40 months after operation respectively.The first day after the operation,the complete ablation area had hypointensity of DWI,surrounded by annular reaction zone with hyperintensity.The peripheral reaction zone became thinner at 1 month,disappeared basically at 3 months.The ablation focus showed mixed signals.Tumor residual and local tumor progression showed irregular annular or nodular slightly hyperintensity between the ablation area and normal renal tissue.When b value was 800s/mm2,the variation of ADC values changes between different tissues at different time pre-and post-ablation showed that:?ADC values of RCC is lower than that of normal renal tissue.?There was no statistical difference in ADC values between the two groups in the complete ablation zone at each follow-up time after operation,which,however,was significantly different from those before operation.Specifically,ADC values were all decreased.ROC curves were drawn based on ADC values of complete ablation zone and RCC before operation at each follow-up time after operation.The areas under ROC curves were 0.87,0.84,0.86 and 0.85 respectively.On the 1st day after operation,when the threshold value was 1.505x 10-3m m2/s,the sensitivity,specificity and Youdan Index for distinguishing complete ablation zone and RCC were 95.83%,71.79%and 0.676 respectively.?ADC values of different tissues(lesions,peripheral annular reaction zone,and normal renal tissue)at different follow-up times after operation were statistically significant.?There was no difference between ADC values of residual/locally progressive tissues and those of renal carcinoma before operation.ConclusionDue to the different changes in the microstructure of tumor and surrounding tissues after MWA of renal cell carcinoma,theoretically,MR-DWI and ADC values can sensitively reflect this change characteristic in the early stage,effectively distinguish completely necrotic region,active tumor tissue and normal renal tissues,and discover tumor residual/locally advanced tissues.Combined application with CEMRI can improve the detection rate of residual/locally advanced tissues.MR-DWI can provide more diagnostic information than conventional MR when patients cannot be examined with CEMRI due to renal insufficiency or gadolinium allergy.The change of ADC value after operation has high clinical value in early efficacy evaluation. |
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