| Objective :(1)To analyze the imaging features of the focal pancreatic lesions by using contrast-enhanced ultrasound and virtual touch tissue quantification.(2)To evaluate the repeatability of shear wave velocity measurements and the value of shear wave velocity measurements in the focal pancreatic lesions.(3)To investigate the value of contrast-enhanced ultrasound combined with virtual touch tissue quantification in the clinical study of focal pancreatic lesions.Methods : 108 cases from 108 patients with focal lesions of pancreas were collected from January 2015 to January 2017.A total of 108 focal pancreatic lesions were prospectively evaluated with conventional ultrasound,contrast-enhanced ultrasound,and virtual touch tissue quantification.Firstly,pancreatic lesions were observed by conventional ultrasound in multiple sections and Color Doppler flow imaging was used to observe the internal blood flow in the lesions.Secondly,select the best observation section of the lesion into the imaging mode,and inject 2.4ml Sonovitzy in the elbow mid-vein group,observing the change of the lesion in real time.Time-intensity curves were recorded by the CEUS quantitative analysis software,comparing the differences of every CEUS parameter between focal pancreatic lesions and adjacent normal pancreatic tissue.Sensitivity,specificity and accuracy of the diagnosis were assessed through ROC curve differences analysis.To do the acoustic radiation force impulse imaging exam,the probe perpendicularly touched the surface of the lump area,placing the lump in the center of the sampling frame,which is about 2 times size of the lump area.Obtain virtual touch tissue images when patients held their breath.Switching to VTQ mode,SWV values were measured at the lesion and the region of interest of the adjacent pancreas parenchyma.The VTQ value of each lesion and corresponding pancreatic background,and the VTQ value of benign and malignant lesion were compared.The threshold of pancreatic VTQ value,which was calculated by ROC curve,was to predict the best cut-off point of pancreatic malignant focal lesions.According to the pathological results,the value of diagnosing Pancreatic solid focal lesions by SWV of the lesion,SWV of adjacent pancreatic parenchyma,and the differences of SWV between the two groups was evaluated.For the patients who were clearly diagnosed with advanced pancreatic cancer and accepted follow-up adjuvant treatment,the size of the lesion was observed.The one-way random effects model was selected to count the intraclass correlation coefficient to evaluate the repeatability of SWV measurements.Results:(1)In 54 cases of malignant pancreatic lesions,14 cases(25.93 %)showed uniform enhancement and 40 cases(74.07 %)showed uneven enhancement.In 54 cases benign pancreatic lesions,19 cases were cystic lesions,in which CEUS showed 26.32%(5/19)no enhancement,73.68%(14/19)showed enhancement in cystic wall and separation;in 35 cases of solid cystic lesions,5.71%(2/35)had no enhancement,25.71%(9/35)had uneven enhancement,68.57%(24/35)are enhanced.There was statistical difference between benign and malignant lesions(P<0.05).(2)In 33 cases with definite pathological diagnosis of pancreatic cancer,25 cases(75.76%)showed persistent hypo-enhancement,and 8 cases(24.24%)showed iso-enhancement in the arterial phase and hypo-enhancement in the venous phase.The accuracy,negative predictive value,positive predictive value,specificity and sensitivity,using hypo-enhancement as a sign of pancreatic cancer,were 93.1%,97.5%,87.5%,90.7% and 96.6%,respectively.(3)Compared with conventional ultrasound,combined diagnosis(conventional ultrasound and CEUS)or CEUS had a less scores of 3 while more scores of 1 and 5(P<0.05).There were significant differences between the two techniques in diagnosing benign and malignant pancreatic lesions(P<0.05).Meanwhile,there was no significant difference between the combined diagnosis and CEUS in diagnosing benign and malignant pancreatic lesions(P>0.05).(4)The TIC quantitative parameters of focal pancreatic lesions presented that the onset of malignant pancreatic lesions was significantly later than that of the adjacent pancreatic parenchyma(P<0.05).While there was no difference in the onset time of the adjacent pancreatic parenchyma and benign lesions(P>0.05).The wash in slopes comparison among pancreatic other benign tumors,pancreatic inflammatory lesion,pancreatic neuroendocrine tumors,pancreatic cancer :PNETs> OBTs> PIL> PC(P<0.05);1 min washout slope comparison: OBTs <pNETs <PC <PIL(P<0.05);Area under the curve and peak intensity ratio’s comparison: pNETs>OBTs>PIL>PC(P<0.05).(5)The average SWV of the adjacent pancreatic parenchyma in malignant group was 1.61 ± 0.61m/s(0.75-3.23m/s),while the malignant lesions was 2.41 ± 1.23m/s(0.59-4.40m/s)in SWV.The average SWV of the adjacent pancreatic parenchyma in the benign group was 1.46 ± 0.39m/ s(0.79-2.24m/s),and that of the benign lesions was 2.08 ± 1.06m/s(0.77-4.02m/s).There was a significant difference in mean SWV between lesions and adjacent parenchyma in both groups(P<0.05).SWV difference between benign and malignant groups,adjacent pancreatic parenchyma’s SWV and the lesion’s SWV showed no difference(P> 0.05).(6)In SWV measurement,the mean intra-group correlation coefficient of five parenchyma lesions was 0.869,and the mean intra-group correlation coefficient of five measurements of pancreatic parenchyma was 0.895.(7)In 14 patients with advanced pancreatic cancer who underwent adjuvant therapy,the mean SWV value was(0.90±0.34)m/s in the no-remission group and(2.90±0.82 m / s)in the having-remission group(P<0.05).(8)In the diagnosis of focal pancreatic lesions,there was no statistic difference in the area under the ROC curve of CEUS and combined method(CEUS and ARFI).However,the area under the curve of both was higher than that of ARFI(P <0.05).The specificity,sensitivity and accuracy of ultrasonography were 91.7 %,94.4 % and 82.5 % respectively,The specificity,sensitivity and accuracy of acoustic palpation were 81.3 %,80.2 % and 80.6 % respectively,The specificity,sensitivity and accuracy of ultrasonography combined with acoustic palpation were 93.6 %,97.3 % and 92.6 % respectively,There was statistical difference(P < 0.05).Conclusion:(1)SWV measurement is of good repeatability.Multiple measurements can improve the reliability,accuracy of the result.(2)The prognosis of advanced pancreatic cancer may choose the initial lesion SWV.(3)With the combination of CEUS microcirculation perfusion information and conventional ultrasound macro images,the diagnosis of focal lesions of the pancreas will be further improved.(4)The accuracy,specificity and sensitivity of ultrasound combined with quantitative techniques of acoustic palpation were significantly increased in the diagnosis of pancreatic focal lesions. |
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