| Part 1 CTE imaging and energy spectrum characteristics of normal small intestineObjective The CTE image characteristics and energy spectrum characteristics of small intestine in normal people were observed.Methods Thirty patients who underwent CTE combined with GSI in the First Affiliated Hospital of Anhui Medical University from July 2018 to April 2020 were selected as the observation objects.The patients were divided into group A(18-30 years old,n = 6),group B(31-50 years old,n = 13)and group C(? 50 years,n = 11).The imaging features and energy spectrum characteristics of CT plain scan and dual phase enhancement were observed: 1)The optimal iodine(water)concentration and the best single energy in arterial phase were measured on spectral CT images.2)The best single energy level of each patient was measured with intestinal fluid as background.The best single energy group image was obtained by the best contrast to noise ratio(CNR)single energy curve.3)The thickness of intestinal wall and the diameter of intestinal canal after filling were measured,and the difference of wall thickness and filling degree of different parts of small intestine was compared.4)Each segment of the small intestine was observed to see if there was intestinal wall stratification.5)The CT value and single energy CT value of each segment of small intestine wall were measured and compared.The above data were measured by two senior doctors in the Department of radiology.Results 1)The iodine(water)concentration and CNR distribution of GSI images in groups a,B and C were statistically analyzed.The results showed that the iodine(water)concentration and CNR distribution in the small intestine of normal people of different age groups had a certain range,and the difference was not statistically significant(P > 0.05).2)The average thickness of intestinal wall of duodenum,jejunum and ileum was(2.02 ± 0.18)mm(1.60mm-2.50mm).There was no significant difference in the thickness of duodenum,jejunum and ileum(F = 0.126,P = 0.901).The diameter of small intestine with good filling was 15.00 mm-35.20 mm,with an average of(22.60 ± 2.85)mm.The average diameter of duodenum,jejunum and ileum after filling was statistically significant(F = 7.095,P= 0.001).3)The CT value of normal duodenum was(29.16 ± 4.00)Hu,that of jejunum and ileum was(29.00 ± 3.81)Hu and(28.90 ± 3.90)Hu,respectively.There was no significant difference in CT value of each segment of small intestine(F = 0.255,P = 0.801).The average CT values of the small intestine wall in arteriovenous phase were(65.30 ± 10.05)Hu and(81.50 ± 11.50)Hu respectively,and the difference was statistically significant(t = 5.810,P < 0.001).The CT values of duodenum,jejunum,ileum in arterial phase and venous phase were 73.50 ± 6.88 vs 86.33 ± 10.85,68.50 ± 9.11 vs 80.0 ±10.26 and 58.65 ± 9.73 vs 78.40 ± 10.20,respectively.4)There was no significant difference in CT value of duodenum,jejunum and ileum in plain scan(P > 0.05).In arterial phase and venous phase,there were significant differences in CT values between 40 ke V and 100 ke V segments(all P < 0.05),while there was no significant difference in CT values between 110 ke V and 140 ke V(P > 0.05).Conclusion It is helpful for the diagnosis and differential diagnosis of intestinal diseases to master CT quantitative parameters and energy spectrum curve characteristics of CTE segments in normal populationPart 2 Diagnostic efficacy of energy spectrum CT for terminal ileitisObjective To observe the image characteristics of gemstone energy spectrum CT imaging(GSI)and compare its diagnostic efficacy with that of conventional CT enterography(CTE)in the diagnosis of terminal ileitis.Methods Case-control study was used,120 patients who were initially diagnosed as terminal ileitis in our hospital from Dec.2015 to Apr.2019 were randomly selected as the objects of observation.Among them,70 patients were examined by conventional CTE from Dec.2015 to Jun.2018,and 50 patients were examined by GSI from Jul.2018 to Apr.2019.Observed the characteristics of the images(single energy imaging,energy spectrum curve and iodine base map)of terminal ileitis on GSI.The gold standard was pathological examination results obtained by colonoscopy,the sensitivity and specificity of the two methods in the examination of terminal ileitis were compare,drew(receiver operating characteristic curve,ROC)curve of the two methods and compared the difference of area under the curve(area under curve,AUC).Results The results showed that the lesions were clear on low KeV single energy imaging;the energy spectrum curve could clearly identify the lesion wall,the normal wall,the fluid in the intestinal cavity and the adjacent fat;the iodine concentration in the arterial and venous phase of terminal ileitis was(10.90 ± 0.55)and(14.33 ± 0.75)?g/cm3,respectively.70 patients were examined by conventional CTE,and 43 patients were confirmed to be terminal ileitis by pathology;50 patients were confirmed by GSI,and 29 patients were confirmed to be terminal pathology by final pathology.41 cases of terminal ileitis were reported by conventional CTE,but only 28 cases were diagnosed correctly by pathology.The sensitivity and specificity of CTE were 65.1% and 51.9% respectively.28 cases of terminal ileitis were reported by GSI,25 cases were diagnosed correctly by pathology.The sensitivity and specificity of GSI were 86.2% and 85.7% respectively.The sensitivity and specificity of GSI were significantly better than that of CTE(P sensitivity = 0.046,P specificity = 0.014).The AUC of GSI was 0.860,which was better than that of CTE(Z = 2.420,P= 0.015).Conclusion GSI can clearly show the imaging characteristics of terminal ileitis.It has better diagnostic efficacy for terminal ileitis than conventional CTE. |
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