| Objective: Using 64-slice spiral CT scanning features, to reconstruct the clear axial thin and coronal, sagittal images, and to observe various peritoneal structure performance, position and anatomic landmarks in normal conditions, so as to provide the basis for clinical diagnosis of peritoneal disease.Methods: During 2014 January to 2014 December,among the patients who were treated for abdominal plain CT scan and enhanced scan in the Department of Radiology Hebei Medical University second hospital, 60 patients were selected to meet the inclusion criteria of the subjects(age range: 20 to 60 years, mean age 45 years; sex ratio 5:5). All the raw data collected were processed with multiplanar reconstruction(MPR), getting the coronal and sagittal images. The images were checked by physicians with senior, intermediate and junior titles and they got the consensus. The author observed and described the peritoneal structure(omentum, mesentery and ligament), including the anatomical position, the relationship with the surrounding tissues and organs, the hallmark of vessels display cases and lymph nodes, and measured the CT value of lipid component and the lymph node size, and conducted the statistical analysis on the measured value using t test and variance analysis.Results:1 Peritoneal structure has different characteristics in different parts, but the main ingredients are fat, it contains abundant fibrous connective tissue and small blood vessels, mainly displaying dot, thin strips of the vessels. Hereinafter the various structure of peritoneum is to described.2 The structure of gastric colon ligament is fat and blood vessels. In plain scan gastroepiploic vessels resolution is not clear. In the enhancement scanning, gastroepiploic vessels detection rate was 100%, mainly displaying the form of spots or stripes shadow of the vessels. The gastrocolic ligament fat composition is slightly higher than subcutaneous fat in the same layer, It has no significant change for enhanced scan CT value. A few can see a single lymph node, whose diameter is smaller than 5mm.3 Free omental part is in motion. According to the moving parts it is mainly divided into three types:(1) in front of the jejunum and ileum(2) the centre right abdominal cavity(3) in the upper abdominal cavity. The main component of the free omental part is adipose, including abundant blood vessels, such as gastroepiploic vein and gastric colic vein. The left and right gastroepiploic artery and vein were displayed in 100%(60/60). The display rate of gastrocolic vein is about 68.3%(41/60). The fat composition is similar in the free omental part and gastrocolic ligament. Lymph node appears few, and the diameter is smaller than 5mm.4 In the Omental sac it has hepatogastric ligament, hepatoduodenal ligament, the gastrosplenic ligament and lienorenal ligament. The observation range of the ligament is accorded to the vessel form and fat composition. The left gastric artery and vein, right gastric artery is a sign of liver stomach ligament; portal vein, hepatic artery is a sign of the hepatoduodenal ligament; the left gastroepiploic artery and short gastric arteries is a sign of the gastrosplenic ligament; the mark of lienorenal ligament is the splenic artery and vein. Vascular diameters of each part are different, but there was no significant difference in CT value between the vascular fat with the abdominal cavity and retroperitoneum in same layer(P ≥0.05). There are some important recess in omental bursa, they are linked closely. The CT value is different, but the fat composition is similar.5 Small bowel mesentery vascular displayed roughly radially. Vessel boundary is clear, but with the increase in vascular branching, distal branches will be more and more fine, but the overall situation can be observed in the displayed layer of superior mesenteric artery coronal and inferior mesenteric artery. Small bowel mesentery seen in the left upper quadrant are almost mesojejunum; in the left lower abdomen it is mesojejunum mainly; Small bowel mesentery seen in the right lower quadrant are the ileal mesentery; and in right upper quadrant the ileal mesentery is accounted for the bulk. Small bowel mesentery observed in the pelvic cavity is ileal mesentery generally. The fat density in mesenteric is homogeneous, and it has no obvious change after enhancement. Its fat component is slightly higher than the layer underneath. Small intestinal mesentery and its root has few lymph nodes, and the diameter is smaller less than 5mm.6 It has colonic artery and vein branch within transverse mesocolon. The axial display rate of middle colic artery is higher than the coronal, and the sagittal display is the worst. Middle colic vein is in line with the middle colic artery, and it flows into the superior mesenteric vein anterior or right anterior and flows toward right under. According the vessel form we can determine the transverse mesocolon position, and most of the transverse mesocolon are located in the upper abdominal cavity. The fat composition in transverse mesocolon and small bowel mesentery are similar. The display rate of lymph node is very low, and its diameter is smaller than 5mm.7 In CT images, the inferior mesenteric artery and inferior mesenteric vein is originated from abdominal aortic anterior wall, and flow toward left front and below forming the mutually concomitant vascular shadow in the sigmoid mesocolon. The axial observation of sigmoid mesocolon is best, and it often locates in the sigmoid colon side. A few can be observed in the rear part of the pelvic small bowel. The fat composition is similar between sigmoid mesocolon and small bowel mesentery, and it has no significant change in enhancement condition. It has no lymph node displayed.Conclusion:1 Using 64 slice spiral CT scan can display various anatomical structure of peritoneum well.2 The gastroepiploic vessels can be seen as a sign of gastrocolic ligament; superior mesenteric artery and inferior mesenteric artery is a marker of small bowel mesentery; signs of transverse mesocolon is colon arteriovenous, symbol of the inferior mesenteric artery and inferior mesenteric vein is observation marker of the sigmoid colon mesentery.3 The free part of greater omentum is in motin. According the vessel form of each ligament in the omental, we can judge the position of the ligaments roughly.4 The fat density in the greater omentum and omental pouch is homogenous. It is lightly higher than intraperitoneal and retroperitoneal part in the same layer, while it is slightly higher than subcutaneous fat.5 The fat density in small intestinal mesentery, transverse mesocolon and sigmoid mesocolon is homogenous, and is slightly higher than the subcutaneous tissue.6 The show rate of all lymph nodes in peritoneal is low, and their diameter is smaller than 5mm. |
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