The Diagnostic Value Of CT And MRI In Benign And Malignant Tumors For Primary Retroperitoneal

Objective: To retrospectively analyze the CT and MRI features of 83 cases with primary retroperitoneal tumor and evaluate the accuracy of CT and MRI in localization,qualitative,pathological diagnosis and differential diagnosis.Methods:Clinical and imaging information of 83 patients with primary retroperitoneal tumor after biopsy or pathological resection in our hospital were collected from January2017 to October 2019.The CT and MRI manifestations were observed,according to the tumor’s growth patterns,location,blood supply and some of its characteristic components(calcification,cystic degeneration or necrosis,fat,mucous matrix),and compared with pathological results,comparing the difference of CT and MRI in judging the localization,differentiating benign or malignant and estimating the pathological type for primary retroperitoneal tumor.The statistical analysis of all data was carried out by using SPSS21.0 software,the specific contents included :(1)The sensitivity and specificity of CT or MRI signs in the diagnosis of partial pathological types were calculated.The forma is that the sensitivity is equal to the number of true positive/true positive+false negative,the specificity is equal to the number of true negative/true negative+false positive.(2)Chi-square test was used to analyze the morphological features and internal components and the relationship between benign and malignant,sensitivity and specificity were used for diagnostic ability.P<0.05 was considered statistically significant.(3)The long and short diameter of tumors were statistically analyzed by the rank sum test of two independent samples(Mann-Whitney U Test),then the ROC curve was made to obtain the optimal diagnostic threshold,sensitivity and specificity.Results:1.Among the 83 cases of primary retroperitoneal tumors,44 cases(53%)were benign tumors,39 cases(47%)were malignant tumors.25 cases(30.1%)were lobar tumors,38 cases(45.8%)were neurogenic tumors,9 cases(10.8%)were lymphoid tumors,4 cases(4.8%)were genitourinary tumors,and 7 cases(8.4%)were other tumors.2.There were 7 cases misdiagnosed as adrenal sources,2 cases misdiagnosed as sources of kidneys and 4cases misdiagnosed as sources of abdominal cavity.CT and MRI showed no statistical difference in the location,benign and malignant judgment and pathological type estimation of primary retroperitoneal tumors(x~2=1.578,P=0.372;x~2=1.391;P=0.474;x~2=0.576,P=0.748).3.The shape,boundary,invasion or not in diagnosis of benign and malignant were statistically significant(x~2=25.984、87.596;x~2=32.435、93.676;x~2=17.508、91.646,P<0.001).The diagnosis of primary retroperitoneal tumor based on calcification,cystic change or necrosis,fat or lipid were not statistically significant(P>0.05).Either the long diameter or the short diameter were statistically significant in judging the nature of lesions(P=0.000).The optimum diagnostic threshold was length diameter >7.6cm and short diameter >6.25 cm.The sensitivity,specificity of diagnosis were 84.6%,69.2% and 75.0%,79.5% respectively.The sensitivity and specificity in diagnosing malignant lesions were 84.6% and 90.9%(c 2=47.732,p=0.000)when the total scores beyond 2.5 by using combined score(irregular morphology,unclear boundary,long diameter >7.6cm,short diameter >6.25 cm,invasion of surrounding tissues,1 point for each of the above ones).4.The sensitivity and specificity of cystic degeneration or necrosis for paraganglioma and schwannoma were 90.9%,52.1% and 76.9%,52.1% respectively.The sensitivity and specificity of significantly enhanced in diagnosing paraganglioma were 100% and 71%.The sensitivity and specificity of fat in the diagnosis of liposarcoma were 72.7% and93.3%.All the neurogenic tumors were located in the spinal column or in the anterior sacral sympathetic chain.The sensitivity and specificity of peritoneal vascular growth to lymphoma were 100% and 98.7%.Conclusion:1.The CT and MRI have the same value for judging the tumor’s localization,benignancy or malignancy and the estimation of pathological type.But for the recognition of the components inside the tumor,the two are complementary.2.The size,morphology,boundary and invasion or not are valuable for the judgment of benign and malignant;the internal components of tumor(calcification,cystic change or necrosis,fat)are of no value to the judgment of benign and malignant,but it can narrow the differential diagnosis.3.combined score can improve the accuracy of diagnosis.