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Ileal arteries

The ileal arteries are multiple small branches of the superior mesenteric artery (SMA) that supply the ileum, the distal portion of the small intestine. They arise from the left side of the SMA, run obliquely downward and to the right within the mesentery, and anastomose with jejunal arteries proximally and with one another to form arterial arcades. From these arcades arise straight vessels (vasa recta) that penetrate the intestinal wall to supply the mucosa, submucosa, and muscular layers.

The ileal arteries, together with jejunal arteries, form multiple short and complex arcades with comparatively short vasa recta (in contrast to the jejunum’s long vasa recta). This vascular arrangement supports the high absorptive function of the ileum.

Clinically, the ileal arteries are important in small bowel ischemia, Crohn’s disease, intestinal obstruction, bowel resections, and interventional radiology procedures for GI bleeding. Their detailed mapping is crucial in surgical planning and in embolization therapy.

Synonyms

  • Ileal branches of the superior mesenteric artery

  • Arteriae ileales

Function

  • Supply oxygenated blood to the ileum via mesenteric arcades and vasa recta

  • Contribute to collateral circulation within the small intestine

  • Provide rich blood flow essential for nutrient absorption

MRI Appearance

T1-weighted images:

  • Ileal arteries appear as thin linear flow voids (black lumens) within mesenteric fat

  • Best visualized with high-resolution abdominal sequences

T2-weighted images:

  • Arteries appear as signal voids against the intermediate signal of mesentery and bowel wall

  • Perivascular edema or inflammatory changes highlight their course

STIR:

  • Suppresses mesenteric fat, improving visualization of the arteries

  • Inflammation, mesenteric edema, or Crohn’s disease appear hyperintense

T1 Fat-Saturated (Pre-contrast):

  • Lumens may appear with intermediate signal intensity, clearly contrasting against suppressed mesenteric fat

  • Helps distinguish vessels from lymph nodes or mesenteric masses

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Ileal arteries enhance brightly and homogeneously

  • Demonstrates mesenteric arcades and vasa recta

  • Useful for detecting active hyperemia, vascular anomalies, or ischemia

MRA (Magnetic Resonance Angiography):

  • Shows ileal arteries branching from SMA, forming short arcades with vasa recta

  • Provides vascular mapping in Crohn’s disease, ischemia, or pre-surgical evaluation

  • Non-invasive tool for detecting stenosis or arterial narrowing

CT Appearance

CT Pre-Contrast:

  • Arteries appear as small soft-tissue density structures in mesentery, usually indistinct from fat

  • Calcifications may be seen in older patients with atherosclerosis

CT Post-Contrast:

  • Ileal arteries enhance brightly, visible as multiple branches within mesentery

  • Highlights arcades and terminal vasa recta supplying ileum

  • Useful in detecting mesenteric hyperemia, ischemia, or hemorrhage

CT Angiography (CTA):

  • Gold standard for non-invasive evaluation of mesenteric arteries

  • Shows origin from SMA, branching pattern, arterial arcades, and vasa recta

  • High-resolution multiplanar and 3D reconstructions useful in Crohn’s disease, GI bleeding, ischemia, and surgical planning

MRI image

Ileal arteries MRI coronal anatomy image -img-00000-00000

CT images

Ileal arteries axial ct image

CT images

Ileal arteries coronal ct image