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Ileocolic artery

The ileocolic artery is the lowest branch of the superior mesenteric artery (SMA), supplying the terminal ileum, cecum, appendix, and proximal ascending colon. It descends obliquely downward and to the right, crossing the retroperitoneum toward the ileocecal junction.

At the ileocecal region, it divides into ileal, colic, anterior cecal, posterior cecal, and appendicular branches, forming rich anastomotic arcades with the right colic artery, anterior and posterior cecal arteries, and terminal ileal branches.

Clinically, the ileocolic artery is important in appendectomy, right hemicolectomy, Crohn’s disease resections, and GI bleeding embolization. It also plays a major role in collateral mesenteric circulation, providing redundancy in case of SMA or colic artery compromise.

Synonyms

  • Arteria ileocolica

  • Ileocaecal artery

Function

  • Supplies blood to the terminal ileum, cecum, appendix, and proximal ascending colon

  • Provides the appendicular artery, the sole arterial supply of the appendix

  • Contributes to marginal artery of Drummond, ensuring collateral colonic blood flow

  • Supports lymphoid tissue in the ileocecal region

Branches

  • Ileal branch → supplies terminal ileum, anastomoses with SMA branches

  • Colic branch → supplies proximal ascending colon

  • Anterior cecal artery → anterior cecal wall

  • Posterior cecal artery → posterior cecal wall

  • Appendicular artery → vermiform appendix

MRI Appearance

T1-weighted images:

  • Appears as a linear flow void (black lumen) coursing toward the ileocecal junction

  • Surrounded by mesenteric fat (hyperintense on T1)

T2-weighted images:

  • Vessel seen as a signal void against bowel wall and mesenteric fat

  • Inflammation (e.g., Crohn’s disease) may highlight course due to perivascular edema

STIR:

  • Fat suppression improves artery visibility in mesenteric fat

  • Perivascular edema, abscess, or inflammation shows as hyperintensity

T1 Fat-Saturated (Pre-contrast):

  • Lumen typically appears intermediate signal, standing out against suppressed fat

  • Aids in differentiating artery from adjacent mesenteric structures

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Ileocolic artery enhances brightly and homogeneously

  • Useful in detecting ischemia, neovascularization, and tumor-related vascularity

MRA (Magnetic Resonance Angiography):

  • Contrast-enhanced MRA shows origin from SMA, its course to ileocecal region, and branching pattern

  • Helpful in pre-surgical mapping, GI bleed evaluation, and mesenteric ischemia

CT Appearance

CT Pre-Contrast:

  • Appears as a soft-tissue tubular structure in mesentery

  • Calcifications may be seen in older patients with atherosclerosis

CT Post-Contrast:

  • Enhances brightly, showing its descent from SMA to ileocecal junction

  • Demonstrates anterior/posterior cecal and appendicular branches

  • Useful for identifying active GI bleeding (contrast extravasation)

CT Angiography (CTA):

  • Gold standard for detailed mapping

  • Multiplanar and 3D reconstructions show origin, course, and full branching anatomy

  • Critical for surgical planning, embolization, ischemia, tumor vascular supply, and appendiceal artery visualization

MRI images

Ileocolic artery MRI coronal anatomy image -img-00000-00000

CT images

Ileocolic artery CT axial anatomy image -img-00000-00000

CT images

Ileocolic artery CT axial anatomy image -img-00000-00000_00001

CT images

Ileocolic artery CT axial anatomy image -img-00000-00000_00002