Comparison Of Multi-slice Spiral CT And Capsule Endoscopy In Diagnosing Obscure Gastrointestinal Bleeding

Part one: study on multi-slice CT entrography for normal human small intestineObjectives: To inspect hypotonic multi-slice CT entrography(MSCTE) for normal human small intestine assisted by isotonic solutions of mannitol.Methods: MSCTE images of patients with satisfactory bowel filling and clinical and imaging diagnosis were collected from the First People’s Hospital of Nantong between November 2011 and January 2013. A total of 20 cases were included in the study, 11 male and 9 female with a mean age of 48.9±15.3 years. Excluded were those patients who had digestive system diseases, malignant tumors in other regions of the body, autoimmune disease, hepatic cirrhosis, heart failure, mental diseases or iodine allergy. Before the examination, patients received 1500~2000ml of 2.5% isotonic solution of oral mannitol at three different times, once every 15 mins. Siemens Somatom Sensation 64-slice spiral CT was applied for the examination. First performed was plain scan, after which the patients received intravenous administration of 370 mg Iml-1iopromide and underwent arterial phase and portal venous phase scans. Post-scan processing included multi-planar reconstruction(MPR), maximum intensity projection(MIP) and volume rendered technique(VRT). Two experienced doctors good at gastrointestinal diseases endoscopy diagnosis inspected the images of normal small bowels for canal diameters of filled bowel,attenuation values of bowel wall and its thicknesses. These values were measured twice and the mean value of the two readings were then analyzed with STATA9.0, results considered statistically significant when P<0.05.Results:(1) The mean diameter of filled normal small bowel was 18.3±3.7mm with no statistical differences(P>0.05) among different regions.(2) The mean thicknesses of normal bowel wall was 2.3±0.4mm, different regions having no statistical differences(P>0.05).(3) The attenuation values of normal small bowel canal during plain scan,arterial phase scan and portal venous phase scan were respectively 29.1±2.0HU,61.0±2.8HU and 79.1±4.7HU, no statistical differences(P>0.05) being found in different regions at the same phases.(4) The attenuation values of bowel walls in different scan phases showed statistical differences(P<0.05).(5) 49 out of 60(81.7%) mesenteric vessels were successfully imaged.(6) 19 cases of patients received hypotonic enterography, one of which had diarrhea after the examination and the rest showed no adverse reactions.Conclusions:(1) Hypotonic multi-slice CT entrography with oral isotonic solutions of mannitol can clearly display the structure of small bowel wall and mesenteric vessels.(2)A better understanding of MSCTE for normal intestine is helpful for the diagnosis and differential diagnosis of small intestine diseases.Part two: imaging techniques of MSCTA for normal human small intestineObjectives: To optimize the post-imaging processing methods by evaluating the performance of multi-slice CT angiography(MSCTA) in superior mesenteric artery(SMA)ramification imaging and its ability of continuous display when different methods are applied.Methods: Imaging records of patients who had multi-slice CT enterography(MSCTE)in combination with MSCTA in the First People’s Hospital of Nantong between November2011 and January 2013 were collected. All cases had satisfactory bowel filling and clinical and imaging diagnosis. Those who had digestive system diseases, malignant tumors in other regions of the body, autoimmune disease, hepatic cirrhosis, heart failure, metal diseases or iodine allergy were ruled out. In the 60 cases chosen for the study, 35 weremale and 25 were female, aged 45.0±12.7 years. Scanning methods and parameters were the same as in Part One. The captured raw images were delivered to the workstation for the reconstruction of mesenteric artery and its branches. Reconstruction methods included multiplanar reconstruction(MPR), thin maximum intensity projection(thin-MIP) and volume rendering technique(VRT). Both the conventional coronal view(parallel to the long axis of SMA main trunk) and the oblique coronal view(parallel to the long axis of ileocolic artery or jejunal arteries) were processed by thin-MIP. Two experienced radiologists good at gastrointestinal diseases diagnosis observed the reconstructed images independently. Performances data of the five processing methods in displaying the four branches of SMA and its continuity were analyzed by SPSS16.0 and with Chi-square test and Fisher’s exact test. The results were statistically significant when P<0.05.Results:(1) MSCTA showed that 9 to 13 jejunal arteries branched out from the superior mesenteric artery and later displayed were 3 to 8 jejunal arteries and 3 to 7ileocolic arteries.(2) As for displaying ileocolic arteries, middle colic arteries and jejunal arteries to at least their tertiary branches, thin-MIP, in both conventional coronal view and oblique coronal view, was, showing more ramifications, better than VRT and MPR(P<0.05).(3) For displaying ileocolic and middle colic arteries to the tertiary branches and more, thin-MIP in oblique coronal view was better than in conventional coronal view(P<0.05).(4) In displaying jejunal arteries and ileocolic arteries for their ramifications, no statistical differences were found of thin-MIP in oblique coronal view and in conventional coronal view(P>0.05).(5) Comparing with other five simple processing methods,combining both views in thin-MIP could notably increase the successful rate of displaying jejuna and ileocolic arteries to their tertiary branches and more(P<0.05).(6) VRT had better performance than MPR and thin-MIP in a continuous display of the whole artery course(P<0.05).(7) For a complete display of the artery ramification, thin-MIP in both views was obviously better than in single view(P<0.05).Conclusions:(1) Combining MSCTA and MSCTE in one examination can play out the advantages of both, promoting the display of mesenteric vessels and improvinglesions location and qualitative diagnosis.(2) For displaying ileocolic arteries, middle colic arteries and jejunal arteries, thin-MIP in the conventional coronal view had better images than MPR and VRT.(3) For displaying the distant branches of the four main trunks of SMA and for a continuous display of the artery course, thin-MIP in both views was obviously better than only in the conventional coronal view. As a convenient and effective post-imaging processing method, combining both views in thin-MIP is recommended as the common method for processing images of mesenteric artery CTA.Part three: comparison of multi-slice spiral CT and capsule endoscopy in diagnosing obscure gastrointestinal bleedingObjectives: To explore the differences between capsule endoscopy(CE) and multi-slice CT enterography(MSCTE) in combination with MSCT angiography(MSCTA)in diagnosing obscure gastrointestinal bleeding(OGIB).Methods: Enrolled in the study were OGIB patients from the First People’s Hospital of Nantong between May 2008 and September 2013. After screening to certain criteria, the selected cases were then numbered chronologically and grouped randomly, using SPSS,into MSCT group, CE group and MSCT&CE group. 127 cases in all completed the examination, of which 82(aged 42.7±19.1 years; 34 males) received MSCT diagnosis, 67(aged 53.9±16.2 years; 28 males) received CE diagnosis, and 22(aged 54.1±19.1 years; 12males) received both with the examination interval of 2 to 6 days and a mean interval of3.52±2.70 days. For the MSCT examination, patients received oral mannitol 2.5% isotonic solution, intramuscular anisodamine injection and post-scan intravenous administration of non-ionic contrast(370mg Iml-1iopromide). Afterwards, multiphase scans consisting of arterial phase, small intestinal phase, and portal venous phase were applied and followed by the same processes as described in Part Two. With bowel preparation for patients in the same way, the CE examination was performed using an OMOM capsule endoscope from Jianshan Science and Technology Group Co. Ltd, Chongqing, China. MSCT and CE images were reviewed respectively by two groups of doctors, one group of radiologistsspecializing in digestive tract diseases diagnosis and the other of gastroenterologists engaging in gastrointestinal diseases endoscopy diagnosis. Each group had two doctors and both doctors had over ten years of clinical experience. Within the group, the two doctors would discuss to reach a conclusion when they read different results. Gold standards included double balloon enteroscopy(DBE), digital subtraction angiography(DSA),intraoperative pathological examination and/or clinical diagnosis. All data were analyzed with SPSS v. 19.0 and considered statistically significant when P<0.05.Results:(1) Administration of anisodamine significantly increased the satisfaction rate of bowel filling(94.67% vs 28.57%; P<0.001) but not the diagnostic yield(P=0.293)of MSCT.(2) Compared with MSCT, CE showed an improved overall diagnostic yield(68.66% vs 47.56%; P=0.010), which was also observed in patients under 40 years old(85% vs 51.28%; P=0.024) and having overt bleeding(76.19% vs 51.02%; P=0.013).(3)CE and MSCT had similar positive predictive values in diagnosing OGIB(P=0.05).(4) No significant differences were found between CE and MSCT in their diagnostic efficiency among the 22 cases that had both examinations(P=0.4597).Conclusions:(1) Both CE and MSCT are noninvasive, safe and effective diagnostic methods for OGIB.(2) CE is the first choice for examining OGIB patients, especially those who are under 40 years old or show overt bleeding.(3) Either of CE and MSCT has its own advantage, and if use wisely, OGIB will be better diagnosed.