Diffusion-weighted Imaging (DWI) Evaluation And Clinical Application Of Chemotherapy Put Monitoring Before Cancer Surgery

Purpose:To explore the correlation of Apparent Diffusion Coefficient (ADC) and pathological features of cervical cancer by ADC histogram analysis.Material and Methods:111patients with cervical cancer proven by biopsy who performed preoperative MRI including diffusion weighted imaging with b values of0and800s/mm2before radical resection within2weeks were retrospectively studied. ADC maps and ADC Histogram were reformated by GE post-processing software. Regions of interest were drawn around entire tumor excluding hemorrhagic, necrotic and cystic regions on each consecutive tumor containing slice. The average of ADCmean,ADCmin obtained from all tumor containing slices and the5th to95th percentile ADC values every10percent derived from the largest cross-sectional area of lesions were measured for each patient. ADCmin, percentile ADC values and ADCmean were compared between subgroups according to pathologic subtype, histological differentiation, depth of cervical infiltration and presence of lymph node metastasis or lymphovascular invasion. Receiver Operating characteristics (ROC) analysis was performed in order to evaluate the diagnostic performance of ADC value in differentiating pathological features of cervical cancer. According to the ROC curves, the optimal cut off value was extracted. Relevant factors of ADC values were analyzed by multiple stepwise regression.Results:ADCmean, any percentile ADC value and ADCmin for squamous cell carcinoma were significantly lower than that of adenocarcinoma (P<0.0001) ADCmean for differentiating squamous cell carcinoma from adenocarcinoma had a largest Az (0.882), p<0.05, A cut-off value of1100.2×10-6mm2/s for ADCmean in differentiating squamous cell carcinoma from adenocarcinoma with a specificity of89.2%, a sensitivity of88.9%. Only ADCmin and low percentile ADC values(ADC50%-ADC55%) were significantly different among different grades of squamous cell carcinoma, P<0.05. ADC5%for differentiating well/moderately from poorly differentiated squamous cell carcinoma had a largest Az(0.831), p<0.05, Threshold value of686.5X10"6mm2/s for ADC5%in differentiating well/moderately from poorly differentiated squamous cell carcinoma with a specificity of82.6%, a sensitivity of82.9%. There was no statistical difference in ADC values for different depth of cervical infiltration, lymph node with/without metastasis, lymphovascular with/without invasion, p>0.05. Only pathological type and degree of differentiation were selected to multivariate regression equation.Conclusion:ADC values are helpful in identifying squamous cell carcinoma from adenocarcinoma, differentiation of cervical squamous cell carcinoma. The role of different type of ADC value is different.There is a correlation between ADC values of cervical cancer and pathological subtype, differentiation, respectively. Purpose:To explore whether DWI is superior to conventional MRI in diagnosis of lymph nodes metastasis in patients with cervical cancer. To establish the thresholds of Apparent Diffusion Coefficients(ADC) values and morphology indexes in diagnosis of lymph nodes metastasis of cervical cancer.Material and Methods:42cervical cancer patients confirmed by operation and pathology examination who performed preoperative MRI including diffusion weighted imaging with b values of0and800s/mm2before radical resection within2weeks were retrospectively studied. Two radiological doctors fully blinded to the clinical data and histological characteristics of cervical cancer. Preoperative MR images of cervical cancer patients were analyzed and all lymph nodes with a short diameter≥5mm in axial sequence were included in this study.3cervical cancer patients with pelvic lymphatic metastasis and3patients without lymphatic metastasis were randomly selected, lymph nodes of these patients with a short diameter>5mm were identified by two doctors in consensus, short-axis(S) and long-axis diameters (L), ADCmin, ADCmean of lymph nodes and ADCmin, ADCmean of primary tumors were independently measured. L/S ratio, rADCmin and rADCmean(defined as the ratio of lymph node ADC value to the primary tumor ADC value) were independently calculated by two doctors. The inter-observer consistency of the measurements were assessed by using Bland-Altman analysis. MR images of the remaining36patients(18patients with pelvic lymphatic metastasis and18patients without lymphatic metastasis) were independently analysed by two doctors. The location of lymph nodes were recorded. The above morphology indexes and ADC values were measured. MRI findings were compared with the post operative pathologic findings in all cases. The morphology indexes and ADC values were compared between metastatic and non-metastatic lymph nodes. Receiver operator characteristic curve(ROC) analyses were performed in order to identify optimal cut-off value for L, S, S/L ratio, ADCmin, ADCmean, rADCmin, rADCmeain the diagnosis of lymphatic metastasis. The optimal thresholds were selected as the diagnostic criteria of lymphatic metastasis.Inter-observer agreement for classification of metastasis on regional level by conventional MRI or DWI were respectively tested by Kappa statistics.Results:The inter-observer consistency of morphology indexes and ADC values measurement were good. Long-axis diameter, Short-axis diameter, S/L ratio of metastatic lymph nodes were significantly longer than non-metastatic ones, P<0.05. The ADCmin, ADCmean, rADCmin, rADCmean of metastatic lymph nodes were significantly lower than non-metastatic ones, P<0.05. The Az of the ADCmin(0.918) was largest, P<0.05. An optimal cut-off ADCmin of757.9×10-6mm2/s for differentiating metastatic from non-metastatic lymph nodes with a sensitivity of88.0%, a specificity of84.7%. The Az of ADCmin, ADCmean, rADCm=in, rADCmean were significantly greater than L or S/L ratio-based criteria, P<0.05. Only the Az of ADCmin was significantly greater than S-based criteria, P<0.05. The Kappa value for agreement of metastasis diagnosis on regional level by conventional MRI or DWI was0.543,0.528, respectively, P<0.05.Conclusion:Diagnostic performance of DWI in differentiating metastatic from non-metastatic pelvic lymph nodes in patients with cervical cancer is better than the conventional MRI. Inter-observer agreement for classification of pelvic lymphatic metastasis on regional level in cervical cancer is moderate. Purpose:To investigate the value of ADC histogram analysis based on monoexponential signal decay model and DWI with multiple b values based on biexponential signal decay model in accessing cervical cancer response to concurrent chemoradiotherapy.Material and Methods:Twenty-eight patients with cervical cancer proven by biopsy who received concurrent chemoradiotherapy were prospectively included. Pelvic MR scans were performed before therapy within2weeks,7days and21days after the therapy initiated,1month after the treatment completed. DW1with b values of0,800s/mm2and b values of0,50,450,850s/mm2were performed respectively in all cases. Tumor volumes, ADCmin,5th to95th percentile ADC values every10percent (ADC5%, ADC15%…ADC955%), ADCmean,ADCslow、 ADCfast、Ffas were measured at each time point of MR examination. Poor or good clinical outcome was defined according to with/without tumor residue, recurrence, distant metastases during follow-up(9-25.5months). Tumor volumes before therapy and tumor shrinkage rate1month after conclusion of therapy were compared between groups of good and poor clinical outcome. Variation tends of tumor volumes and ADC values at different time points before and after treatment were analysed. ADC values and its rate of change at each time point were compared between different outcome groups.Results:Tumor volume before therapy and tumor shrinkage rate1month after conclusion of therapy were not statistically different between good and poor outcome group(P>0.05). Pretreatment ADCmin,ADC5%and ADCslow for good clinical outcome were significantly higher than those of poor clinical outcome (P<0.05). ADCfast and its rate of change before and after treatment were not significantly different between good and poor outcome group(P>0.05).Ffast andits rate of change were significantly higher in good outcome group than that in poor outcome group7days after the therapy initiated (P<0.05). Ffast during treatment in good outcome group significantly higher compared with pretreatment ones(P<0.05), while Ffast gradually increasing in poor outcome group, were not significantly higher than that of pretreatment(P<0.05). Only the absolute value of change rate of ADCslow in good outcome group was significantly higher than that in poor outcome group1month after conclusion of therapy.Conclusion:ADCmin, ADC5%, ADCslow before the start of the treatment, variation tendency of Ffast before and after therapy, change rate of ADCslow1month after conclusion of therapy have the potential to predict the outcome of cervicalcancer to concurrent chemoradiotherapy.