1621710 SMA superior mesenteric artery 2841 3457442 SMAs superior mesenteric arteries 29 3457637 SMAO superior mesenteric artery 4 431615 SM superior mesenteric artery 3 1568320 SAM superior mesenteric artery 2 2057754 SMA-RI superior mesenteric artery 1 3457413 SMAT superior mesenteric artery 1 1629505 SNA superior mesenteric artery 1