Study Of Achieving CTE Scan By Use Of Bolus Tracking On SMV

Objective: Discovering the relationship between superior mesenteric vein(SMV)and small intestinal wall enhancement effect in contrast-enhanced CT scan and performing the single-phase enhanced CTE scan with a novel SMV contrast agent tracking technique.Compared with traditional aortic contrast media tracking technique.Methods: Contrast-enhanced CT scan was performed on midsection of patients without intestinal disease,we monitored ROI on SMV and small intestinal wall in case to achieve the relevance of time and enhancement effects,and then determine the threshold CT value,and we used these to perform SMV bolus tracking and automatic triggering scan to complete CTE examination.At the same time,retrospectively study the same patients were performed conventional three-phase CTE examination.Then,we compared the images obtained by these two methods.Contents:(1)We chose patients without entric desease and performed midsection contrast-enhanced CT scan.During the examination,experienced radiologist selected a layer that can show the duodenal wall and SMV.Two small ROIs were placed at the duodenal intestinal wall and SMV as monitoring points.The layer was scanned continuously after injecting contrast agents in 35s~55s,average interval was 1s,then we got the CT attenuation value of duodenal wall and SMV at every points of time.We concluded the intensity-time relevance of enhancement effects of them.,and then get the SMV CT value when the duodenal wall enhanced effect is strongest,determine threshold of starting scan.(2)We chose some patients without hemorrhage of digestive tract and performed CTE examination for them.Unlike conventional enhanced CT scans that ROI was placed in the aorta,we placed ROI in SMV,then set the corresponding threshold to finish single phase CTE scan by using automatic triggering technique.The image data were transferred to the post-processing station,we completed the reconstruction of the image and measure record the CT value of each part of intestinal wall to evaluate the strength of its enhancement effects.(3)Retrospective study of nagetive patients who had finished three-phase CTE scan.Using traditional aortic contrast media tracking technique,we placed the ROI in the abdominal aorta 1 cm below the diaphragm.For obtaining image,we set the corresponding threshold and completed the three phase enhanced scan including arterial phase,intestinal phase and portal phase by use of automatic trigger scanning technology.The image data were transferred to the post-processing station to reconstruct the image.Then we measured and recorded the CT value of each section of the intestinal wall in the three phase,in order to evaluate the strength of its enhancement effect.These data and the data acquired from single-phase enhanced CTE in(2)were analyzed statistically.At the same time,more than two experienced deputy(or above)physician performed a double-blind comparison of the diagnostic efficacy of the images obtained from(2)and(3).Result:(1)The average time to peak of SMV subjects is 45.83 ± 6.037 s after injection of contrast agent,and duodenal intestinal wall is 40.24 ± 8.907 s.The different between them is not statistically significant.The average CT value of duodenal wall is 65.87±8.246 HU at the time 4seconds earier than SMV reach the peak.(2)The subjects who the diagnosis of CTE is negative that use SMV contrast agent tracking technology for single-phase enhanced scan of each group of bowel intestinal wall average CT values are: duodenal is 115.63±15.38HU、jejunum is 108.57±12.82 HU 、 ileum is 90.35 ± 13.34 HU.There are no statistically significant in the different CT value of the intestinal wall between the duodenum and the jejunum(P>0.05).(3)The subjects who the diagnosis of CTE is negative that performed three-phase enhanced scan by using aortic contrast agent tracking technology.The CT value of duodenum,jejunum,ileal gut were 65.68±15.36HU、64.61±20.23HU、60.18±12.25 HU in arterial phase,117.66±29.87HU、 110.37±24.92HU、87.54±18.19 HU in enteric phase,85.76±30.09 HU,、78.03±15.43HU、68.56±14.42 HU in portal phase.The CT value of duodenum,jejunum,ileac gut in intestine phase were higher than that in portal and arterial phase,and the differences were statistically significant(P<0.05)and there are no statistically significant in the different CT value between arterial and portal phase(P>0.05);.The differences of the CT value of the intestine wall between SMV method and aortic method were not statistically significant(P>0.05).Conclusion: It is feasible that CTE enhanced scanning use contrast media tracing technique on SMV,and the image quality obtained by this way is as good as the enteric phase that gets best contrast ratio by traditional aortic tracing method.