The Value Of ¹⁸F-FDGPET/CT In Differentiating Noninvasive From Malignant Pancreatic Cystic Lesions?PCLs? And Comparison With CT And MRI

Part One The value of¹⁸F-FDG PET/CT in differentiating noninvasive from malignant pancreatic cystic lesions?PCLs?Objective As the development of imaging technology,more and more pancreatic cystic lesions?PCLs?are detectable.The role of ¹⁸F-FDG PET/CT in diagnosing pancreas cancer is very important,but there is no clear position for the examination in the diagnosis of PCLs so far.The research aim to discuss the value of ¹⁸F-FDG PET/CT in differentiating noninvasive from malignant PCLs.Methods Retrospective analysis of patients with PCLs confirmed by pathology or follow-up from 2010.08 to 2015.12 who had ¹⁸F-FDG PET/CT examination in our nuclear medicine department.A total of 125 patients had pathology or typical imaging performance with ?12 months follow-up.There are 59 females and 66 males,age from 13 to 83 years old,and 74 cases had pathological results,1 case had surgical exploration result,50 cases were followed up.132 PCLs were found in 125 patients?1 female and 6 male patients had two separate PCLs?.The accuracy,sensitivity,specificity,positive predictive value,and negative predictive value of ¹⁸F-FDG PET/CT examination were calculated by using pathological or follow-up results as gold standard.Noninvasive and malignant PCLs' size,SUVmax,delayed SUVmax and RI are analyzed using SPSS¹⁸.0 software?when P<0.05 has statistical significance?.If every parameter obey normal distribution and satisfy homogeneity of variance test,then we can do the t test,otherwise do nonparametric test.Draw receiver operating characteristic?ROC?curve of SUVmax,delayed SUVmax and RI,and compare the differences between them.Results The median values of size,SUVmax,delayed SUVmax,RI are 2.2?0.7⁹.1?vs 3.9?1.0¹0.3?cm,1.5?0.5⁷.4?vs 6.4?1.1²0.9?,1.5?0.4⁷.7?vs 6.4?1.1²2.5?,-6.3?-40.6²6.7?vs 17.5?-9.6⁶8.2??%?respectively.The size,SUVmax,delayed SUVmax and RI between noninvasive and malignant PCLs have significant statisti cal differences?P<0.05?.SUVmax's area under the curve?AUC?and cutoff values are 0.969 and 2.5 by drawing ROC curve,corresponding accuracy,sensitivity,specificity,positive predictive value,negative predictive value are 92.4%,93.0%,91.8%,93.0%,91.8%,respectively.Delayed SUVmax's AUC and cutoff value is 0.969 and 2.7,corresponding accuracy,sensitivity,specificity,positive predictive value,negative predictive value are 94.3%,96.7%,91.1%,93.5%,95.3%,respectively.SUVmax and delayed SUVmax have no significant difference,but SUVmax and delayed SUVmax have higher diagnostic efficacy than RI.Conclusion The¹⁸F-FDG PET/CT examination have high value in differentiating noninvasive from malignant PCLs.Malignant PCLs' size,SUVmax,delayed SUVmax and RI are higher than noninvasive lesions generally.The SUVmax > 2.5 and delayed SUVmax > 2.7 indicate malignancy,delayed scan failed to further improve the diagnostic efficacy of ¹⁸F-FDG PET/CT in differentiating noninvasive from malignant PCLs.Part Two Comparison of ¹⁸F-FDG PET/CT,enhanced CT and MRI in differentiating noninvasive from malignant pancreatic cystic lesionsObjective Comparison of ¹⁸F-FDG PET/CT,CT and MRI in differentiating noninvasive from malignant pancreatic cystic lesions.Methods The group of ¹⁸F-FDG PET/CT and enhanced CT: retrospective analysis of patients who had ¹⁸F-FDG PET/CT and enhanced CT examination meanwhile during the period from 2010.8 to 2015.12.There were 47 patients?19 females and 28 males,aged 24⁸1 years old?satisfied the condition.26 patients had pathological results,1 patient had surgical exploring results,and 20 patients confirmed by follow-up.A total of 50 pancreatic cystic lesions?PCLs?were founded?3 female patients had two separate lesion?.The group of ¹⁸F-FDG PET/CT and MRI: retrospective analysis of patients who had ¹⁸F-FDG PET/CT and MRI examination meanwhile during the period from 2010.8 to 2015.12.There were 61 patients?39 patients had enhanced MRI and 22 patients had only MRCP,19 females and 28 males,aged 26⁸1 years old?satisfied the condition.34 patients had pathological results and 31 patients confirmed by follow-up.A total of 65 PCLs were founded?4 female patients had two separate lesions?.Calculate the accuracy,sensitivity,specificity,positive predictive value and negative predictive value of ¹⁸F-FDG PET/CT,enhanced CT and MRI examination through crosstabulation.Compare ¹⁸F-FDG PET/CT with enhanced CT and MRI using ?2 and Kappa test,then get the level of each method's diagnostic efficacy.Results The accuracy,sensitivity,specificity,positive predictive value and negative predictive value of ¹⁸F-FDG PET/CT vs enhanced CT were 94.0% vs 82.0%,95.8% vs 75.0%,92.3% vs 88.5%,92.0% vs 85.7%,96.0% vs 79.3% respectively.The accuracy,sensitivity,specificity,positive predictive value and negative predictive value of ¹⁸F-FDG PET/CT vs MRI were 96.9% vs 83.1%,96.8% vs 83.9%,97.1% vs 82.4%,96.8% vs 81.3%,97.1% vs 84.8%respectively.Only the combined ?2 test's value of ¹⁸F-FDG PET/CT vs MRI less than 0.05,all the value of Kappa test less than 0.40.The results combined ?2 test with Kappa test reveal that the accuracy,sensitivity and specificity of ¹⁸F-FDG PET/CT disagreed with enhanced CT and MRI examination.We can speculate that ¹⁸F-FDG PET/CT has higher diagnostic efficacy in differentiating noninvasive from malignant PCLs than enhanced CT and MRI examination.Conclusion It suggests a trend that the diagnostic efficacy of ¹⁸F-FDG PET/CT in diagnosis of PCLs is superior to the enhanced CT and MRI examination.