Splenic artery arising from the superior mesenteric artery: analysis of morphological characteristics with contrast-enhanced CT images

Purpose To elucidate morphological characteristics of the splenic artery (SA) arising from the superior mesenteric artery (SMA). Methods Contrast-enhanced CT images of 13 patients with SA arising from SMA were retrospectively analyzed. Gross appearance of SA arising from SMA was observed on volume-rendering 3D images. Additionally, we measured the following lengths m each patient on the appropriate multiplanar reformation (MPR) images; (A) the distance from the origin of SMA to the origin of SA, (B) SA length from the origin of SA to the point which is at the shortest distance from the celiac artery (CA), (C) the shortest distance between CA and SA, (D) the distance from the origin of SA to the origin of the middle colic artery. Results In all 13 patients, SA arising from SMA showed similar course. It first runs cranially toward the point which is very close to CA, and then curves toward the left and afterwards runs along almost the same course as the conventional SA. The shortest distance between SA and CA (distance C) was 3.3 ± 1.4 [mm]. Conclusion SA arising from SMA invariably shows characteristic morphology. This characteristic morphology suggests that longitudinal anastomosis between primitive CA and SMA may be the developmental basis of this variant vascular anatomy.