Application Of MDCT In Assessment Of Peripancreatic Vascular Invasion In Pancreatic Ductal Adenocarcinoma

Part one:Prediction of Vascular Invasion Using a Three-Point Scale CT Grading System in Pancreatic Ductal Adenocarcinoma:Correlation with SurgeryObjective:To evaluate the correlation between a 3-point scale multidetector computed tomography(MDCT)grading system and surgical exploration in predicting vascular invasion and resectability in patients with pancreatic ductal adenocarcinoma(PDA).Methods:Fifty-seven patients with surgical and pathologic confirmation of PDA were retrospectively analyzed by 2 abdominal radiologists independently.All patients had MDCT examination with cross axial images,multiplanar reformatted(MPR)images,CT angiography(CTA).The location and size of the tumor was recorded.Based on the lastest Clinical Practice guidelines of National Comprehensive Cancer Network(NCCN)and expert consensus of PDA,a 3-point scale CT grading system of tumor-to-vessel contact(TVC)was used in evaluating the invasion of 5 main peripancreatic vessels(CA,HA,SMA,PV and SMV).The Spearman correlation coefficient was used to analyze the consistency of the results of two doctors in the evaluation of the classification of vascular invasion.And consistency analysis was made on the grading evaluation results of CT and surgical vascular invasion for each vessel.With the results of operation and pathology as control,Areas under the receiver operating characteristic curve(ROC)was used to assess the diagnostic efficiency of MDCT prediction of tumor resectability associated with peripancreatic vascular invasion.The tumor size was correlated with the outcome of the3-point scale CT grading system for peripancreatic vascular invasion.Results:Tumor location was correctly identified in all patients.There was a high consistency between the results of peripancreatic vascular invasion assessment by two abdominal radiologists using TVC 3-point scale CT grading system(r=0.791,P=0.000).After the two readers had consistent opinion,the CT grading results of the 5 main peripancreatic vessels were in good agreement with the results of surgical(r=0.809,P=0.000)?The consistency of CT and surgical grading in the venous group(PV?SMV)was better than that in the arterial group(CA?HA?SMA)(venous group r=0.829,P=0.000,arterial group r=0.602,P=0.000).The sensitivity,specificity,PPV,NPV,and accuracy of MDCT were 90.5%(38/42)?80.0%(12/15)?92.7%(38/41)?75.0%(12/16)and87.7%(50/57),respectively,in predicting tumor resectability associated with peripancreatic vascular invasion compared with surgery and pathology.The AUC was 0.852(95%CI,0.723 0.982),high diagnostic efficacy was demonstrated.The correlation between the tumor size and the TVC grading of peripancreatic vessels was poor(r=0.340,P=0.008)in 57 cases and so does pancreatic head/uncinate process adenocarcinoma(r=0.468,P=0.001).On the contrary,the correlation between the tumor size and the TVC grading of peripancreatic vessels was high in pancreatic body/tail adenocarcinoma(r=0.710,P=0.000).Conclusions:The 3-point scale CT grading system is a simple and practical method in predicting peripancreatic vessel invasion,the CT grading results are in good agreement with the results of surgical.And importantly,it can be used in predicting tumor resectability associated with peripancreatic vascular invasion,the diagnostic efficacy is high.The tumor size of pancreatic body/tail adenocarcinoma is closely related to peripancreated vascular invasion.Axial images combined with MPR and CTA can strengthen the comprehensive evaluation of peripancreatic vascular invasion.Part two:Evaluation of Peripancreatic Vascular Invasion in Pancreatic Ductal Adenocarcinoma using MDCT Vessel Analysis SoftwareObjective:The purpose of this study was to preoperatively evaluate peripancreatic vessels invasion on MDCT using tumor-to-vessel contact(TVC)and luminal narrowing rate(LNR)by vessel analysis software(VAS)in patients with pancreatic ductal adenocarcinoma(PDA).Methods:Seventy-five patients who had been surgically and pathologically diagnosed with PDA were retrospectivelyanalyzed.All patients underwent non-enhanced and dual-phase enhanced CT examinations.Based on the latest National Comprehensive Cancer Network(NCCN)guidelines and a recent consensus statement,vessel resectability evaluation was determined by the TVC and LNR criteria using the VAS.Spearman analysis was performed to evaluate the consistency between the two reviewers.ROC image analysis and Kappa test,taking LNR value with the highest sensitivity and specificity as the cutoff level.The results of LNR and TVC combined LNR grading evaluation were compared with the operation grade,and the consistency was evaluated.Coronary resection of vascular invasion was predicted by TVC,LNR and TVC combined LNR,and the results of CT vascular invasion in all cases were compared with the surgical resectability.The sensitivity?specificity?Positive predictive value(PPV)and negative predictive value(NPV)and accuracy of each method were obtained,and compared the area under the ROC curve(AUC/Az)to evaluate the predictive accuracy of each method.Results:(1)Based on the VAS software,the consistency between the two readers was high(r=0.904,P=0.000).(2)29%was the cutoff level of LNR.Using 29%as the cutoff level of LNR,the consistency between the two readers was high(r=0.861,P=0.000).(3)The results of LNR and TVC combined LNR were consistent with the surgical grade(r=0.781,P=0.000;r=0.729,P=0.000).The consistency of assessment in the vein group was slightly higher than the arterial group.(4)According to the TVC criterion,tumor resectability had a sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV),and accuracy of 95.9%,80.8%,90.4%,91.3%,and 90.7%,respectively.When the LNR was determined>29%as a threshold for vessel unresectability,the corresponding values were 93.9%,84.6%,92%,88%,and 90.7%,respectively.When the LNR was combined with TVC,the corresponding values were91.8%?92.3%?95.7%?85.7%and 92.0%,.The area under ROC curve(A_Z)was 0.940,and the diagnostic performance was highest.Conclusion:MDCT uses VAS software to provide objective and quantifiable data for the assessment of the major peritumoral vascular invasion of the PDA,improving the consistency of the results of different diagnostic physician evaluations.LNR can be used for the assessment of peripancreatic vascular invasion when LNR>29%is used as a critical threshold for tumor and vascular inseparability.The specificity,PPV and accuracy of TVC combined with LNR in predicting the resectability of peripancreatic vascular invasion are higher than those of TVC or LNR alone,and the diagnostic efficacy is the best.