Multislice CTA depicts celiac artery variants

The celiac artery is the largest artery in the abdomen and supplies a number of major upper abdominal organs, including the liver, spleen, stomach, and pancreas, through its branches. An appreciation of this arterial anatomy is important when planning surgery and image-guided interventions.

The success of procedures such as liver transplantation, intestinal anastomosis, intra-arterial chemotherapy, chemoembolization, and radioembolization, requires a detailed knowledge of the celiac artery and its branches. This should include an awareness of any anatomical variants, which are extremely common in these vessels. For instance, when embolization in the liver is planned, it is essential that interventional radiologists know of any variations in the blood supply feeding the liver tumors and surrounding organs. This knowledge may help achieve complete embolization at the target site and also prevent embolic materials from straying into other vessels.

Angiography is the gold standard for demonstrating vascular anatomical variants. But it is invasive and carries the risk of procedural complications. The use of noninvasive techniques, such as CT and MRI, in this role has been limited by the low resolution of images and slow acquisition speeds. The introduction of multislice CT (MSCT) scanners, which enable large volumes of data to be acquired within a few seconds, means that high-resolution 3D imaging can now be performed easily.

Reformatted CT images, obtained with various software tools, can be used to demonstrate the celiac vascular anatomy and its relationship to other structures, the bile duct and portal vein, for example. CT angiography can also display arterial anatomy in different planes and projections, similar to the images obtained with angiography. MSCT has consequently become a valuable noninvasive tool for imaging normal vascular anatomy and its variants and pathological conditions affecting major abdominal vessels.

FROM NORMAL TO ABNORMAL

The celiac artery arises from the ventral surface of the abdominal aorta at the level of the 12th thoracic vertebra and T12-L1 intervertebral disc space. It courses caudally for a short distance, then forms a branching structure. The classic description of normal celiac anatomy is that the main trunk trifurcates into the left gastric artery, the splenic artery, and the common hepatic artery¹ (Figure 1). In fact, the length and course of the celiac artery are variable and its branches frequently arise separately from the trunk. Several other branches may additionally arise from the celiac trunk, for example, inferior phrenic arteries, the dorsal pancreatic artery, and the middle colic artery.² Variations on normal celiac arterial anatomy are also often associated with branching pattern variants of the superior mesenteric artery.

Variations to the aorta’s anterior branches can be explained embryologically. ³ The paired dorsal aorta gives rise to a series of paired vitelline arteries, also called primitive digestive trunks, which are the precursor to the future digestive vessels. As the vitelline arteries fuse, the 10th pair usually forms the celiac artery, the 13th pair forms the superior mesenteric artery, and the 21st or 22nd pair forms the inferior mesenteric artery.