PurposeTo investigate the effects of the low concentration contrast medium combined with optimal single source spectral imaging on displaying feeding arteries of gastrointestinal tract malignant tumors.Materials and Methods Seventy-one patients of body mass index (BMI) >25 kg/m2 with gastrointestinal tract malignant tumors were prospectively studied. All the cases were randomly divided into two groups: high concentration group (33 cases with high concentration contrast medium of 350 mgI/ml in routine scan) and low concentration group (38 cases with low concentration contrast medium of 270 mgI/ml in optimal single source spectral imaging). The optimal single source images were generated automatically. The subjective image scores, CT value of the tumor feeding arteries, image noise, contrast-to-noise ratio (CNR) and CT dose index of volume (CTDIvol) of optimal single source spectral images in two groups were compared. Results The optimal single source of low concentration group were 51-60 keV. The subjective image score of low concentration group was higher than high concentration group (Z=-4.280,P<0.01). The consistency between the two investigators was good (Kappa=0.824 and 0.843,P<0.05). The consistency between the two investigators in evaluating CT value of the tumor feeding arteries, CT value at the right erector spinal muscle, image noise and CNR data was good (ICChigh concentration group=0.998, 0.968, 0.959 and 0.990; ICClow concentration group=0.988, 0.981, 0.969 and 0.937). The CT values of the tumor feeding arteries and CNR of the low concentration group were higher than that of the high concentration group, but the image noise was lower than that of high concentration group (t=-14.937, 4.263 and-17.264,P<0.01). There was no statistical difference of CTDIvol between the two groups (t=1.278,P>0.05).Conclusion The low concentration contrast medium with optimal single source spectral imaging in patients with large BMI may improve CTA image quality of feeding arteries of gastrointestinal tract malignant tumors without increasing radiation dose.

Objective To explore the application value of optimal energy imaging technique of monoenergetic dual-energy computed tomography (DECT) in feeding arteries examination of rectal cancer.Methods The clinical data of 33 patients with rectal cancer who were admitted to the First Affiliated Hospital of Dalian Medical University from July 2012 to July 2014 were analyzed retrospectively.The polychromatic and monochromatic images of feeding arteries of tumors were reconstructed and evaluated using a subjective image quality score of 5-point scale by 2 observers.The consistency and scores of evaluation were analyzed by the κ test and MannWhitney U test.The CT value of feeding arteries of tumors and hip muscle,image noise and contrast to noise ratio (CNR) were measured and calculated by 2 observers,and were compared by the independent sample t test.The consistency of data between the 2 observers were measured by the intra-class correlation coefficients (ICC).Results Inferior mesenteric arteries were contributor of blood supply of tumors in all the 33 patients,including 4 cases with right inferior rectal artery as contributor of blood supply of tumors,2 cases with bilateral inferior rectal artery.Among patients with abnormal blood vessels,there were 8 patients with left colic artery and sigmoid artery having common trunk,4 patients with left colic artery originated from Inferior mesenteric artery,1 patient with absence of left colic artery.The 0-,1-,2-,3-,4-score polychromatic image quality of feeding arteries of tumors were detected in 0,13,13,5,2 patients and 0,11,14,6,2 patients by 2 observers,respectively.The 0-,1-,2-,3-,4-score monochromatic image quality of feeding arteries of tumors were detected in 0,0,7,7,19 patients and 0,0,6,9,18 patients by 2 observers,respectively.Good interobserver agreement was found for the evaluation of subjective scores (κ =0.864,0.897).The subjective scores of image quality of feeding arteries in the polychromatic images and in the monochromatic images were 1.9 ± 0.9 and 3.4 ± 0.8,with significant difference (Z =-5.21,P ＜ 0.05).The latter was superior to the former.The ICC values of the CT values of feeding arteries of tumor,hip muscle,image noise and CNR were 0.953,0.907,0.839,0.964 and 0.966,0.933,0.952,0.962 from the 2 observers,with a good consistency.The CT values of feeding arteries of tumor,gluteal muscles,image noise and CNR in the polychromatic images and in the monochromatic images were (234 ± 52)HU and (412±83)HU,(57±9)HU and (71 ±15)HU,(21 ±3)HU and (31 ±6)HU,9 ±3 and 11 ±4,respectively,with significant differences (t =-18.65,-4.44,-14.14,-6.55,P ＜ 0.05).The levels of monochromatic images of 33 patients were 51-61 keV,with a median of 55 keV.Conclusion The optimal energy imaging technique of monoenergetic DECT can improve the angiographic quality of feeding arteries in patients with rectal cancer.

Objective To assess the utility of single source-dual energy CT for distinguishing bladder cancer from hematoma. Methods We retrospectively identified 14 patients with postoperative or follow-up bladder hematoma who had undergone dual energy protocol (40-140 keV)scanning by single source-dual energy CT.The subjective scoring of tumor detection and image quality,the optimal monochrome images and iodine-water images were evaluated by two radiologists who didn’t know the results.The consistency of two observers was analyzed by Kappa test.Mann-Whitney U test was used to compare the difference between the two kinds of diseases and ROC curve was used to analyze the diagnostic efficiency.The statistical differences of image quality scoring among different images were obtained by using Mann-Whitney U test.Results The consistency of the two observers about scoring of lesion detection was good for all groups.There were statistical differences between two groups in non-enhanced phase and arterial phase of mixed-energy images,non-enhanced phase,arterial phase and delayed phase of optimal monochromatic images,and all phase of iodine-water images. The AUC of iodine-water images in the four phases (0.985,1.000,0.955,0.924,respectively)were all higher than that of polychrome unenhanced and arterial phase images (0.909,0.909).The diagnostic efficiency of arterial phase on iodine-water images was the highest.Sensitivity and specificity were both 100% when score was greater than 2.5.There was no statistical difference between two kinds of diseases on non-enhanced phase,delayed phases of mixed-energy or monochromatic images(P >0.05).There were no statistical differences in image quality scoring among the three groups with the same phases (P>0.05).Conclusion Optimal monochromatic images and iodine-water images of single source-dual energy CT are more effective than conventional CT in distinguishing bladder cancer from hematoma.

Objective To explore the feasibility of axial whole-liver one-stop examination with Revolution CT.Methods Totally 19 patients were underwent upper-abdominal enhanced examination with Revolution CT and acquired whole-liver CT perfusion (CTP),vein phase and balanced phase enhanced images.Two observers recorded the rank and peak CT value corresponding to time-density curve (TDC) of abdominal aorta and portal vein respectively on the CTP images.The perfusion parameters including blood flow (BF),blood volume (BV),hepatic arterial fraction (HAF),mean transit time (MTT),time to peak (TP) of left and right liver lobe were measured.The images of hepatic artery CTA and portal vein CTV were reconstructed and the arterial phase enhanced images were extracted using the images corresponding to abdominal aorta and portal vein peak TDC.And the radiation dose of CT perfusion and one-stop examination were recorded.The differences between perfusion parameters of left and right liver lobe were compared and the consistency of two observers were analyzed.Results The differences between BV and MTT of left and right liver lobe were statistical significance (both P＜0.05).The subjective scores of hepatic artery CTA,portal vein CTV and arterial phase images were greater than 1 point.The two observers were in great consistence (Kappa＞0.6).The effective radiation dose in perfusion phase and one-stop examination were 14.47 mSv and 21.29 mSv.Conclusion With low radiation dose,Revolution CT axial wholeliver perfusion one-stop examination can provide multiple quantitative parameters of liver CTP and clear hepatic artery CTA,portal vein CTV and 3 phase enhanced scan images,which has broadly prospective in clinical application.

Objective To assess the value of spectral CT imaging in distinguishing mass type colorectal adenocarcinoma from colorectal adenoma. Methods Forty patients underwent preoperative abdominal dual energy spectral CT scan were analyzed restrospectively, including 17 with colorectal adenomas and 23 with mass type colorectal adenocarcinomas proven by endoscopic and surgical pathology. All patients underwent plain and three-phase enhanced CT scanning. The conventional polychromatic CT value and its pre- and postcontrast CT values, monochromatic CT value of 40 to 100 keV, the slope of spectral curve and iodine(water) concentration were measured, and the maximum diameter of the lesion was recorded. The maximum diameters of the lesions and imaging parameter differences between the adenomas and adenocarcinomas in plain and three-phase enhanced scan were analyzed with independent sample t tests. The data of the parameters with significant differences were further analyzed by ROC curves. Results The maximum diameters of the adenomas and mass type adenocarcinomas were (1.97 ± 0.54), (2.32±0.53) cm respectively, and there was no statistically significant difference (t=-2.011, P=0.051). There was no statistically differences of the conventional polychromatic CT value and its pre-and postcontrast CT values between the two groups in 4 phases (P>0.05). However, in the arterial phase, the CT values of adenomas were significantly lower than those of adenocarcinomas at low (40, 50 keV) energy (P<0.05). The values did not differ significantly between these two groups at other phases (P>0.05). The slope of spectral curve and the iodine(water) concentration both showed significant differences in the arterial phase between the two groups (P<0.05), while they were not significantly different at other phases (P>0.05).The largest area under the ROC curve of the iodine(water) concentration in the arterial phase was 0.757 in differentiating adenomas and mass type adenocarcinomas, with sensitivity of 73.9%and specificity of 82.4%at the cut-off of 21.02 mg/cm3. Conclusion Spectral CT imaging is valuable in differentiating colorectal adenoma from mass type colorectal adenocarcinoma with the parameters of the arterial phase.

Objective:To analyze and compare the survival rate between patients with screen-detected and non-screening detected colorectal cancer in Shanghai from 2013 to 2015. Methods:Patients with screen-and non-screening detected colorectal cancer from 2013 to 2015 were collected from Shanghai Colorectal Cancer Screening Program and the Population-Based Cancer Registry.The results presented were based on data collected by December 31,2020.Survival rates were stratified by year of diagnosis,gender,site,age-group,stage at diagnosis and histopathologic category when analyzed.The 5-year observed survival rates were calculated based on the life table,and then the cumulative expected survival rates were calculated according to the Ederer Ⅱ method.Finally,the 5-year relative survival rate was calculated.The COX proportional hazard regression model was used for the multivariate analysis. Results:2 108 patients with screening-detected colorectal cancer and 14 154 patients with non-screening colorectal cancer from 2013 to 2015 were included in the analysis,and the proportions of phase Ⅰ were 35.53％and 9.33％,respectively.The stage distribution of colorectal cancer was significantly different between patients with screen-detected and non-screening detected colorectal cancer(P＜0.05).The 5-year relative survival rates of patients with screen-detected and non-screening detected colorectal cancer were 84.66％(95％confidence interval:82.87％-86.45％)and 63.51％(95％confidence interval:62.64％-64.38％),respectively.The patients with screen-detected colorectal cancer had a significantly improved 5-year relative survival rate in comparison with the patients with non-screening detected colorectal cancer.The survival rates of females in both groups were higher than those of males.The relative survival rate decreased with the increase of age and gradually decreased with the increase of stage at diagnosis.The relative survival rate of patients with non-screening detected colon cancer was significantly lower than that of patients with rectal cancer. Conclusion:Patients with colorectal cancer found at screening had a significantly improved survival rate compared to patients with non-screening detected colorectal cancer.Staging at diagnosis is a key factor,which indicates that enhancing screening and early diagnosis has important meaning to further improve the survival of patients with colorectal cancer and reduce the burden of disease.