64-slice Spiral CT Angiography Of Superior Mesenteric Artery: Appearance And Clinical Application

Objective: To investigate the values of 64-slice spiral CT angiography(CTA) on displaying the anatomical characteristics of superior mesenteric artery(SMA) in vivo and its clinical application.Material and Methods: Eighty patients with clinical suspected abdominal or pelvic disease were performed by 64-slice CT angiography, then the image data were processed with different image reconstruction techniques, including volume rendering(VR), multiplanar reconstruction(M PR), maximum intensity projection(MIP), inverse maximum intensity projection (I-MIP) and thin slab maximum intensity projection(TS-MIP). Eighty patients were divided into normal group (30 cases) and abnormal group (50 cases). In the nomal group,the SMA branches were shown at all levels by a variety of reconstruction techniques, Then,the diameters of SMA were measured, the directions of the initial segment of SMA were displayed, the aortomesenteric angles(An) were measured, the distance(M) between SMA and abdominal aorta(AA) were measured at the level of left renal vein(LRV), the maximum anteroposterior diameters(L) of LRV were measured biside the left renal hilum, and the minimum anteroposterior diameter (S) were measured between SMA and AA. In the abnormal group,SMA were shown by a variety of reconstruction techniques.Results:(1)In the normal group, the appearance of holo-SMA can be shown by VR,MIP and I-MIP. TS-MIP was superior to other image reconstruction technique in exhibiting small branches of SMA. There was no significant difference in different reconstruction methods on measuring diameter of SMA(F=0.71,P>0.05).(2)90% of the initial segment of SMA were directed to rightinferior, 6.7% were directed to anteroinferior and 3.3% were directed to leftinferior . The mean of An was (61.06±22.79)°, the mean of M was (14.62±4.00) mm,the mean of L was (9.16±1.91) mm and the mean of S was (6.00±2.01) mm. The ratios of L and S were shown more than 2 in 20.0% and more than 3 in 3.3%.(3)In the abnormal group, there were five cases with congenital intestinal malrotatio, and two cases with intestinal volvulus in which the SMA appeared a'whirl sign'in the axial images and appeared'spiral sign'in VR images. Branches of SMA were embolismed in one case. There were 19 cases with digestive tract tumors among them 8 cases had the feeding arteries origining from the SMA branches. There was one case with ileocecal arterio-venous malformation. The SMA showed no obvious abnormalities in 22 cases with hepatobiliary and(or) genitourinary system diseases.Conclusion: 64-slice spiral CTA can perfectly show the anatomical characteristics of SMA in vivo and has important value in clinical application.