Improvement To Ultrasonographical Differential Diagnosis Of Gastric Lesions: The Value Of Contrast Enhanced Sonography With Gastric Distention

Objective:The purpose of this retrospective study is to evaluate the diagnostic value of contrast enhanced sonography plus gastric distention,the Double Contrast-enhanced Ultrasound(DCUS)in gastric lesions.Method:From June 2014 to June 2016,107 cases with pathology confirmed gastric lesions were retrospectively reviewed,DCUS and conventional gastric distention sonography were performed in all cases prior to operation.By testing against pathological result as reference standard,the diagnostic sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV),and accuracy of US and DCUS for differentiation between benign and malignant gastric lesions were calculated based on every lesion,the diagnostic difference between US and DCUS were analyzed with the Chi-square test.Perfusion parameters including arrival time(AT),peak intensity(PI),time to peak(TTP),and area under the curve(AUC)of the lesion and surrounding normal tissue were analyzed.The differences between different lesions and its neighboring normal tissue were compared by Paired-sample T-tests,and one-way ANOVA was used to compare the difference of each CEUS parameters among the 4 different kinds of gastric lesions.Results:Of the 107 gastric lesions,75 were malignant(33gastric tumors,42 gastrointestinal stromal tumours)and 32 were benign gastric lesions(11 inflammatory masses and 21 polypoid adenomas).Compared with conventional US,DCUS achieved higher value in sensitivity(90.6% vs.70.6%),specificity(75% vs.62.5%),PPV(89.5% vs.81.5%),NPV(77.4% vs.47.6%),and overall accuracy(85.9% vs.68.2%),comparing to conventional US.The increase in correct diagnoses was significant(P =.01)when conventional US was tested against DCUS.Furthermore,gastric cancer had a faster AT,a higher PI and AUC than normal tissue(P<0.05);GIST and Inflammatory mass both had higher PI than normal tissue(P<0.05);Gastric cancer and gastrointestinal stromal tumour(GIST)had a faster AT than polypoid adenoma(P<0.05),Inflammatory mass showed a higher PI than other 3 lesions and gastric cancer had a higher PI than polypoid adenoma and GIST(P<0.05);gastric cancer and inflammatory mass had larger AUC than polypoid adenoma and GIST(P<0.05).Conclusion:1.Ultrasound with oral contrast agent and DCUS could identify malignant and benign gastric lesions.2.DCUS achieved improved diagnostic performance than conventional US,and the accuracy of DCUS was significantly greater than that of ultrasound for differential diagnosis in gasric lesions,which is worth to populate and apply in our clinical work.3.GIST showed a ring like hyper-enchancement after DCUS,this could be a differential point of GIST.4.The combination of different CEUS enhancement characteristics with quantitative perfusion parameters may provide a promising tool to help differentiate gastric cancer and GIST from benign lesions.