Mesenteric Radiographic Anatomy Study

PurposeTo investigate the CT manifestations of the normal small bowel mesentery (SBM), the transverse mesocolon(TM) and the sigmoid mesocolon(SM) in multi-detector spiral CT(MDCT) scanning.Materials and methods1. Research subjects: Plain scan and enhanced contrast study with 16 detector spiral CT scanner were performed in 50 consecutive patients from Nov. 2003 to Mar. 2004 in West China Hospital. Those patients which had no disease revealed on CT images were considered as the normal individuals group, some patients with small liver cyst, renal cyst and liver hemangioma were included. Those patients whose CT images were not fit for the analysis were excluded. 50 cases were 27 males, 23 females, and their ages ranged from 22-64 year.2. CT scanner and scanning parameters: In our study, Siemens sensation 16 CT scanner and Medrad-100 power injector were used. Contrast materialswere Ultravist(Schering, Germany )(300mgI/ml) and Omnipaque (Nycomed, Norway) (300mgI/ml). All of those patients in this study underwent MDCT scan with a scanning coverage from the dome of the diaphragm to the pelvic floor with one-breath-hold. Parameters of CT scans were: 120KV, 165eff mAs, 0.5s/360°; 16X0.75mm, 1 mm MPR reconstruction slice width.3. Image interpretation: Three experienced radiologists reviewed the images, and emphasis was placed on the followning findings: manifestation of major mesenteric vessels such as the vessels located in the SBM, TM and SM; location of the SBM, TM and SM; the correlation of the SBM, TM and SM with their responding bowels; lymph nodes of the SBM, TM and SM; the fat within the SBM, TM and SM.Results1. The revealing rates of the superior mesenteric artery(SMA) and the superior mesenteric vein(SMV) were 100%(50/50) on axial, coronal and sagittal scans of MDCT images; the middle colic artery(MCA) was 86.0%(43/50) on axial and coronal scans of MDCT images; the gastrocolic trunk was 68.0%(34/50) on axial and coronal scans of MDCT images; the inferior mesenteric artery(IMA) and the inferior mesenteric vein(IMV) were 100%(50/50) on axial, coronal and sagittal scans of MDCT images.2. In the left upper quadrant abdomen, the jejunal mesentery was revealed in 98.0% (49/50); in the left lower quadrant abdomen, the ileal mesentery and the jejunal mesentery were revealed in 1OO%(5O/5O); in the right upper quadrant abdomen, the ileal mesentery and the jejunal mesentery were revealed in 92%(46/50); and no SBM was revealed in 8.0%(4/50);13in the right lower quadrant abdomen, the ileal mesentery was revealed in 100% (50/50); the SBM presentated in the pelvis mostly was ileal mesentery.3. The jejunal mesetery and ileal mesentery had different appearance.4. In 29(58.0%)cases, the small bowel was revealed above the middle segment of transverse colon.5. The SM, 36 cases were covered within the study extent, were analysed. In 26(72.2%, 26/36) cases, the SM did not cross the middle line of body. In 13 (36.1%, 13/36)cases, the second segment of sigmoid colon attached to the level above the crista iliac.6. In 6(12.0%) cases, the normal lymph nodes were revealed in the SBM> TM, and were not revealed in the SM.7. The attenuation of the fat located within the SBM, TM and SM was ranged from -82Hu to -120Hu.Conclusion1. The SMA, SMV, MCA, IMA and IMV can be revealed readily on the MDCT images of normal individuals.2. The demonstration of the SBM is best on coronal MDCT images; integrating the axial, coronal and sagittal MDCT images can illustrate the TM completely; combining the axial and sagittal MDCT images can easily demonstrate the SM.3. The MDCT offers important advantages over conventional CT. The axial, coronal and sagittal MDCT images can demonstrate the normal manifestations of the SBM, TM and SM in a certain extent.