The Clinical Value Of Virtual Touch Quantification Technique In The Diagnosis Of Fatty Pancreas

Part 1 The feasibility study of Virtual Touch Quantification Technique for quantitative diagnosis of Fatty PancreasObjective To explore the feasibility of quantitative diagnosis of fatty pancreas(FP)by Virtual touch quantification(VTQ)technique.Methods This study was a prospective study.After excluding the infeasible factors against VTQ technique such as gastrointestinal interference,a total of 97 patients with FP diagnosed by conventional ultrasound and CT scan in the Health Promotion Center of our hospital from October 2017 to June 2018 were selected as the FP group,another 67 subjects with normal pancreas diagnosed by conventional ultrasound and CT scan were selected as the control group.The FP criteria for CT scan diagnosis is:the difference between the pancreas and spleen attenuation(P-S)<-20 or the ratio of the pancreas to spleen attenuation(P/S)<0.7;the conventional ultrasound diagnosis of FP criteria is:pancreatic echo is significantly enhanced by liver,kidney or SMA peripheral tat echo.First,we measured subjects of the FP group including of the anteroposterior diameter of the head,body,and tail of pancreas,and the fat thickness of abdominal wall at pancreatic level as well as the fat thickness around superior mesenteric artery(SMA).Second,we operated VTQ technical examination.The shear wave velocity(SWV)in the region of interest(ROI)of the head,body and tail of pancreas were measured and the corresponding sampling depth was obtained.Then,we recorded the client general clinical data from on-the-spot inquirv and the healthy examination results,but the control group only recorded the name,age and gender and then underwent the pancreatic VTQ technique examination.After that,we compared the difference between the two groups of pancreatic SWV and evaulated the repeatability of VTQ measurements in the FP group.In the end.the correlation between SWV and pancreatic size,fat thickness of abdominal wall at pancreatic level,fat thickness around SMA and general clinical data of patients were analyzed.Results The SWV of the head.body.tail and the integral of pancreas in the FP group was(1.01±0.24)m/s,(1.17±0.29)m/s,(0.99±0.22)m/s and(1.05±0.19)m/s,respectively;the SWV of the head,body,tail and the integral of pancreas in the control group was(1.28±0.15)m/s,(1.42 ± 0.16)m/s,(1.22±0.18)m/s and(1.31±0.13)m/s,respectively.The SWV of different regions of pancreas in the FP group was significantly lower than those in the control group(P<0.001).In addition,there was no significant difference in SWV of different pancreatic regions between different genders in both two groups but there was significant difference in SWV between the different age(age<50 years old and age ?50 years old)sub groups in the control group(P<0.001),while this difference was not shown in the FP group.The correlation analysis of pancreatic SWV in FP group showed that SWV of pancreatic body was negatively correlated with the depth of pancreatic body's ROI(r=-0.200,P=0.049),and the SWV of pancreatic tail and integral pancreas were both negatively correlated with the concentration of triglyceride(TG)(r=-0.31 1,P=0.002;r=-0.226,P=0.026),but the SWV of pancreatic tail was positively correlated with the concentration of high density lipoprotein(HDL)(r=0.205,P=0.044).However,there was no significant correlation between the SWV which was of the remaining regions in pancreas and age,height,weight,body mass index(BMI),abdominal circumference,smoking,fatty liver,systolic blood pressure(SBP),diastolic blood pressure(DBP),pancreatic size,abdominal wall at pancreatic level,fat thickness around SMA,depth of ROI as well as the concentration of TQ total cholesterol(TC),HDL,and low density lipoprotein(LDL)(P>0.05).The same examiner repeatedly measured the SWV of FP with good reliability(ICC>0.75).The receiver operating characteristic(ROC)curve was used to analyze the quantitative diagnostic value of SWV for FP.The area under the curve(AUC)was 0.89(95%Cl,0.83-0.93;P<0.001),and the sensitivity,specificity and accuracy of SWV with the best cut-off value of 1.11m/s was 78.4%,94.0%and 85.4%,respectively.Conclusion The SWV of FP is slower than that of normal pancreas.VTQ as a new ultrasound technique has good reliability,so it can be used as an important auxiliary method for clinical quantitative diagnosis of FP.Part 2 The value of Virtual Touch Quantification Technique in the diagnosis of Fatty PancreasObjective To explore the clinical value of Virtual touch quantification(VTQ)technique in the diagnosis of fatty pancreas(FP)under the standard of CT scan examination result as a definite diagnosis of FP.Methods This study was a prospective study.After excluding the infeasible factors against VTQ technique such as gastrointestinal interference,a total of 56 patients with FP diagnosed by conventional ultrasound in the Health Promotion Center of our hospital from July 2018 to October 2018 were enrolled.Among them.41 patients with FP diagnosed by CT were selected as the positive group and another 15 patients with normal pancreas diagnosed by CT were selected as the false positive group.Besides,40 persons who underwent conventional ultrasound diagnosis of normal pancreas during the same period were selected as the negative group.VTQ technique examination was performed in all groups to measure the shear wave velocity(SWV)of the integral pancreas,and the correlation between pancreatic CT attenuation,spleen CT attenuation,the difference between the pancreas and spleen attenuation(P-S),the ratio of the pancreas to spleen attenuation and the integral pancreatic SWV value was analyzed.The integral pancreatic SWV and general clinical data were compared between the positive group and the false positive group.According to the results of the first part of the study,this study used the integral pancreatic SWV cut-off value? 1.11m/s for the VTQ technique to diagnose the FP.CT was used as the standard for the definite diagnosis of FP,then the ROC curve of VTQ technique and conventional ultrasound for the diagnosis of FP was drawn and the area under the curve(AUC)was calculated to analyze the diagnostic efficiency of VTQ technique for FP.According to the general clinical data and medical history data of the subjects,there were 10 healthy subjects in the false positive group and 5 patients with type 2 diabetes(T2DM),therefore,the false positive group was divided into the healthy group and the T2DM group,and the difference of the integral pancreatic SWV between the two subgroups was compared.Results The pancreatic CT attenuation,P-S and P/S were significantly positively correlated to pancreatic SWV in 56 subjects with FP diagnosed by conventional ultrasound.(P<0.001).and the correlation coefficient r was 0.552.0.556 and 0.568.respectively.The integral pancreatic SWV in the positive group was(1.02±0.13)m/s,and the integral pancreatic SWV in the false positive group was(1.48±0.23)m/s.Obviously,there was a significant difference in the integral pancreatic SWV value between the two groups(P<0.001).There was no significant difference in age,height,weight,body mass index(BMI),abdominal circumference,systolic blood pressure(SBP),diastolic blood pressure(DBP),and the concentration of fasting blood glucose(FBG),triglyceride(TG),total Cholesterol(TC),high density Lipoprotein(HDL),and low density Lipoprotein(LDL)between the positive group and the false positive group(P>0.05).The AUC of VTQ technique and conventional ultrasound for FP diagnosis were 0.89 and 0.86,respectively,the sensitivity were 80.5%and 100.0%,respectively,the specificity were 98.2%and 72.7%,respectively,and the accuracy were 90.6%and 84.4%,respectively.The integral pancreatic SWV in the healthy group was(1.36±0.13)m/s,and that in the T2DM group was(1.70±0.23)m/s.The integral pancreatic SWV in the two subgroups was significantly different(P=0.002).Conclusion VTQ technique can identify and correct some misdiagnosis of FP by conventional ultrasound,and improve the diagnostic accuracy of FP for ultrasonography.In addition,we also find that VTQ has the potential to quantitatively assess the extent of pathological changes in pancreatic tissue of patients with long-term T2DM,but which requires further exploration.