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Ileocolic artery ileal branches

The ileocolic artery is the lowest branch of the superior mesenteric artery (SMA). Among its divisions are the ileal branches, which descend into the mesentery to supply the terminal ileum. These vessels run parallel to the ileal loops, forming vascular arcades with the terminal branches of the ileal arteries that arise directly from the SMA.

The ileal branches of the ileocolic artery ensure collateral circulation to the terminal ileum and ileocecal junction. They also contribute to an anastomotic network with the anterior and posterior cecal arteries, maintaining perfusion even when one branch is obstructed. Clinically, these branches are critical during right hemicolectomy, ileocecal resection, Crohn’s disease surgery, and in cases of mesenteric ischemia or GI bleeding.

Synonyms

  • Ileal branches of ileocolic artery

  • Terminal ileal branches of SMA via ileocolic artery

Function

  • Primary arterial supply to the terminal ileum

  • Contributes to vascular arcades and collateral circulation with SMA ileal branches

  • Provides continuity of perfusion at the ileocecal junction

  • Critical vascular source in surgical resections of ileum and cecum

MRI Appearance

T1-weighted images:

  • Ileal branches appear as thin linear flow voids (black lumen) within mesenteric fat

  • Surrounded by hyperintense mesenteric fat background

T2-weighted images:

  • Vessels appear as signal voids; adjacent inflamed bowel loops (Crohn’s disease, ileitis) appear hyperintense, making vessels more visible

STIR:

  • Suppresses mesenteric fat, improving visualization of arteries

  • Highlights perivascular edema or inflammation as hyperintense signal

T1 Fat-Saturated (Pre-contrast):

  • Arterial lumen often appears intermediate signal, contrasting against suppressed mesenteric fat

  • Helps to distinguish vessels from lymph nodes or fibrofatty mesentery

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Ileal branches enhance brightly and homogeneously

  • Excellent for demonstrating vascular arcades, collateral channels, or neovascularity in Crohn’s disease

MRA (Magnetic Resonance Angiography):

  • Depicts ileal branches from ileocolic artery and anastomoses with SMA ileal arteries

  • Useful for detecting stenosis, occlusion, mesenteric ischemia, or preoperative vascular mapping

CT Appearance

CT Pre-Contrast:

  • Ileal branches appear as small linear soft-tissue densities within mesentery

  • Limited visibility without contrast unless calcifications are present

CT Post-Contrast:

  • Vessels enhance brightly, clearly outlining ileal branches coursing toward terminal ileum

  • Useful in evaluating inflammatory changes, mesenteric hyperemia, or bleeding sources

CT Angiography (CTA):

  • Gold-standard for visualization of mesenteric vasculature

  • Demonstrates ileal branches from ileocolic artery, their arcades, and anastomoses with SMA ileal branches

  • 3D reconstructions allow precise mapping of vascular supply to terminal ileum and cecum

  • Detects stenosis, aneurysms, active GI bleeding, and surgical anatomy

CT images

ileocolic artery ileal branches CT axial anatomy image -img-00000-00000

CT images

ileocolic artery ileal branches CT axial anatomy image -img-00000-00000_00001

CT images

ileocolic artery ileal branches CT axial anatomy image -img-00000-00000_00002