Study On The Value Of Magnetic Resonance Imaging In Normal Small Intestine Wall Structure And The Diagnosis Of Small Intestinal Disease

PART ONEEXPERIMENTAL STUDY OF NORMAL DOG INTESTINAL WALL STRUCTURE ON MRIObjectives:By the high resolution magnetic resonance examination of the small intestine in vivo in dogs, to show the effect of MRI on the display of intestinal wall layers; and by comparative analysis with histology, to evaluate the display capabilities of intestinal wall structure in MRI, so as to provide a valuable theoretical basis for the clinical application of MRI in the examination of small intestine disease.Material and methods:3 adult healthy normal male dogs were selected as experimental animal, and examined with 3.0T MRI. Before MRI examination, food and water were banned for 8-12 hours to the dog. The non fat suppressed T1WI and T2WI and fat suppression sequence T2WI scanning were examined with FSE sequences. For each sequence, the image display and signal characteristics of each layer in different parts of small intestine wall were recorded, the total thickness and each layer thickness of corresponding parts of the intestinal wall were measured; each layer takes small intestine wall thickness ratio was calculated. After MRI examination, the small intestines of dogs were histological specimens according to the location of duodenum, jejunum, ileum, and HE staining was done with followed steps. Motic Images Plus 2 ML digital medical image analysis system was used to multi-range observe and measure of the duodenum, jejunum, ileum, histological sections. The total intestinal wall thickness of each intestinal segment were measured for each site, and the mucosa, submucosa, muscular layer were measured too. The layers thickness was measured three times in continuous 3 pieces tissue, and the average value was recorded; each layer thickness ratio of small intestine was calculated and recorded. The histological and MRI measurement results were analyzed with statistical software SPSS17.0.Results:The FSE sequence of 3.0TMRI can display each layer structure of dog intestinal wall effectively, while the fat suppression T2WI is the valuable scanning sequence. In different part of small intestine, MRI image can display 3 or 4 layers signal of the intestine wall. The mucosal layer of duodenal and jejunal showed two layer signal change, they are medium high signal in the outer layer, and medium signal in the inner layer; jejunum mucosa layer is displayed as a medium signal; the submucosa and muscular signal layer of duodenum, jejunum and ileum were low signal and medium signal separately. In histological measurement, the duodenal was the most thickness wall of the intestinal, followed by the jejunum and ileum. In each layer takes the intestinal wall thickness ratio, the ratio of the duodenal mucosa is the biggest (72.94%±9.33%), followed by the ileal mucosa layer (72.69% ±8.24%), ileum mucosa layer (56.36%± 11.89%); the submucosa and muscular layer ratio of ileum were higher than those in the jejunum and duodenum, thickness ratio accounted for small intestine were 11.91%±8.44% and 31.73%±8.46% separately. There are some certain differences of the small intestine layer thickness between MRI display and histological measurements. The MRI measurement of small intestine mucosa layer thickness and the thickness ratio of mucosa layer are higher than those of histological results; the MRI measurement of layer thickness ratio were 75.80%±8.09% in duodenum,79.46%±4.28% in jejunum, and 55.43%±12.0% in ileum.No statistically significant difference was found in statistical analysis between histology and MRI results.Conclusion:The comparison results with histology experimental show that 3.0T high field MRI can display the layers structure of dog intestinal wall clearly; and the fat suppression T2WI is a valuable scanning sequence, which can provide better evaluation to the signal change of intestinal wall layers.3.0T high field MRI may be useful for further experimental research on small intestinal diseases, especially on the occurrence, development, and the infiltration of quantitative analysis of small intestinal tumors, and can provide important guiding significance on the TNM staging and treatment planning.Conclusion:The comparison results with histology experimental show that 3.0T high field MRI can display the layers structure of dog intestinal wall clearly; and the fat suppression T2WI is a valuable scanning sequence, which can provide better evaluation to the signal change of intestinal wall layers.3.0T high field MRI may be useful for further experimental research on small intestinal diseases, especially on the occurrence, development, and the infiltration of quantitative analysis of small intestinal tumors, and can provide important guiding significance on the TNM staging and treatment planning.PART TWOTHE STUDY OF NORMAL HUMAN INTESTINAL WALL STRUCTURE AND INTESTINAL PERISTALSIS FUNCTION ON MR-CINEABSTRACTObjectives:Based on 3.0T magnetic resonance imagines of the normal volunteers who underwent small bowel examination, the ability of MRI on the display of normal human intestinal wall structure was investigated; and the feasibility and application value of MRI-cine technology assessment on normal small intestine movement ability was researched.Material and methods:3.0T MRI scanner and a 8 channels body coil were applied to abdominal MRI examination of 40 healthy volunteers in our hospital from 2013 June to 2014 February, before examination full preparation of intestinal tract must be made. Firstly, coronal fast spin echo (FSE) T1WI, FSE T2WI, FS-FSE T2WI and fat suppressed FIESTA scanning were scanned, and then the conventional sequence MRI images were analysis and diagnosis by two senior doctors. According to the evaluation standard, image’s overall quality were scored independently; the SNR of normal small intestine wall was measured in the sequence image, and the normal human intestinal wall conventional MRI performance were observed and recorded. Secondly, oral contrast MR scanning was performed to volunteer; and coronal MR-cine scanning were done in not breathe holding condition. The obtained images were transmitted to ADW4.4 post processing workstation. The small bowel segments of the left upper and right lower quadrant were selected as target pair, the intestinal lumen diameter was measured, by drawing the time the intestinal lumen diameter curve, amplitude, movement of small intestine were observed and determined the form of each section of the target intestinal contraction cycle, frequency of contraction and intermission. By drawing the time and the intestinal lumen diameter curve, the movement form of small intestine were observed; and amplitude of each target lumen section, cycle and frequency of contraction, and intermission were determined.Results:All volunteers completed the MRI examination greatly. ① In the conventional MRI sequence, the image quality of FSE T1WI, FSE T2WI, FS-FSE T2WI FIESTA, and fat suppression sequence is better than that of FS-FSE T1WI; and there were significant difference between FS-FSE T1WI and other 4 sequences (P<0.05); but there were no significant difference within the compare of FSE T1WI, FSE T2WI, FS-FSE T2WI, fat suppression FIESTA (P>0.05). ②The signal-to-noise difference was statistically significant in the normal intestinal wall in each sequence (P<0.05), the highest SNR was in fat suppression sequence of FIESTA. ③Normal human small intestine wall was showed best in the FSE T2WI sequence, no statistically significant differences in the thickness of the bowel wall was found in all of the sequence (P>0.05), the range of normal human intestinal wall thickness is 1.2 mm- 3.6 mm, the average is 2.4 mm.④There are statistically significant differences in the number of normal small intestine mucosal folds in the range of 3 cm in each sequence (P<0.05), with FSE T2WI sequence showed the best, FS-FSE T1WI the worst; normal range of 3 cm intestinal segment small intestine mucosal fold number range is 2-9, the average fold number is 5.⑤The difference was statistically significant in number of normal bowel mesenteric vascular branches in the range of 5 cm displays in each sequence (P<0.05), fat suppressed FIESTA sequence showed the best, FSE T2WI sequence the worst; the number range of mesenteric vascular branches within 5 cm normal intestinal segment is 2-13, the average is 6.⑥The time-the intestinal lumen diameter diagram of intestinal MRI-cine shows the types of small intestine movement is continuous contraction with duration of pause; there are significant statistical difference of contraction frequency and duration of pause between the left upper abdominal and right lower abdominal segments (P<0.01); while there are no significant statistical difference in the amplitude and contraction cycle between them.Conclusion:High quality image of normal human small intestine wall can be obtained with 3.0T magnetic resonance images and 8 channel body coil, especially for the FIESTA sequence. The movement ability of normal human small intestine can be evaluated by MR-cine imaging, and quantitative evaluation can be made too; which provides the theoretical foundation for the application of MR-cine imaging to evaluate the small intestine movement condition of organic or functional small bowel disease patients. branches within 5 cm normal intestinal segment is 2-13, the average is 6.⑥The time-the intestinal lumen diameter diagram of intestinal MRI-cine shows the types of small intestine movement is continuous contraction with duration of pause; there are significant statistical difference of contraction frequency and duration of pause between the left upper abdominal and right lower abdominal segments (P<0.01); while there are no significant statistical difference in the amplitude and contraction cycle between them.Conclusion:High quality image of normal human small intestine wall can be obtained with 3.0T magnetic resonance images and 8 channel body coil, especially for the FIESTA sequence. The movement ability of normal human small intestine can be evaluated by MR-cine imaging, and quantitative evaluation can be made too; which provides the theoretical foundation for the application of MR-cine imaging to evaluate the small intestine movement condition of organic or functional small bowel disease patients.PART THREETHE CLINICAL VALUE OF MRI IN DIAGNOSIS OF SMALL INTESTINAL DISEASESABSTRACTObjectives:By the comparison and analysis on the display of small intestinal disease signs and measurement results of 3.0T MRI and CT, and compare with the results of pathology, to investigate the diagnosis value of 3.0T magnetic resonance imaging in the diagnosis of small intestine diseases.Material and methods:52 patients with small bowel diseases were analysised from 2013 June to 2014 September, with complete medical records, and proved by operation and pathology. Before operation,32 patients underwent CT scan with Siemens definition Flash CT (abdominal and pelvic CT common scan in 17 cases, and contrast enhancemen scanning was performed in the rest 15 patients at the same time for abdominal and pelvic CT common scans); after CT examination, MPR post-processing was done to observe different signs and measured.11 patients were applied 3.0T magnetic resonance imaging plain scan with 8 channels body coil, and 4 cases of them also performed contrast enhancement MRI examination. MR examinations were performed using coronal fast spin echo (FSE) T1WI, FSE T2WI, FS-FSE T2WI and fat suppressed FIESTA scanning, some patients using LAVA technology for enhanced MR examination. In all patients, another 9 cases underwent both CT and MR examination. Combined with the histopathological appearance and measurement, the analysis and compare of sensitivity, specificity, accuracy of small bowel disease diagnosis by MRI and CT examination were made respectively, and the effect of basic lesions display was compared too.Results: ①Comparative analysis of results with pathology, the displaying ability of small intestine basic lesion of MRI and CT are high in the sensitive (sN), specificity (sP), and accuracy (AC), and high consistency with histopathological results.②In abnormal intestinal mucosa, surrounding structures involvement display, the sN、sP、 AC results of MRI are higher than those of CT.③Compared with the histological results of tumor size, the intestinal involving length and thickness of the bowel wall thickening respectively, no statistically significant difference between the two examination (CT and MRI) and histopathological findings (P>0.05), but the difference between MR and pathological is smaller than that of CT.Conclusion:With the advantages of high resolution of soft tissues, multi parameter, multi aspect imaging, non ionizing radiation, MRI can show the basic lesions of the small intestine better, and can make up for the lack of CT examination, can help clinical to make accurate and timely diagnosis, to assist clinical choose reasonable treatment. The small bowel motility can be visualized evaluation by MRI-cine, which may guide clinical determine the site of obstruction, and help for the early diagnosis of intestinal obstruction.