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Renal artery

The renal arteries are paired major branches of the abdominal aorta that supply the kidneys. They typically arise at the level of L1–L2 vertebrae, just below the origin of the superior mesenteric artery. The right renal artery is usually longer and passes posterior to the inferior vena cava (IVC), while the left renal artery is shorter and more direct.

Each renal artery courses laterally toward the renal hilum, where it divides into anterior and posterior branches before entering the kidney parenchyma. These branches further divide into segmental, interlobar, arcuate, and interlobular arteries, forming the renal arterial tree.

Anatomical Variations
Accessory (supernumerary) renal arteries are common, occurring in up to 25–30% of individuals. They may arise directly from the aorta or nearby vessels and usually enter the kidney at the hilum or poles. Knowledge of these variants is crucial in renal transplantation, nephrectomy, endovascular procedures, and renal artery stenting.

Clinical Importance

  • Renal artery stenosis (RAS): A major cause of secondary hypertension and ischemic nephropathy, commonly due to atherosclerosis or fibromuscular dysplasia.

  • Transplant surgery: Exact mapping of renal arteries is mandatory in live donor evaluation.

  • Interventional radiology: Embolization procedures for renal tumors, trauma, or vascular malformations require precise renal arterial anatomy.

  • Aneurysms & dissections: Rare but clinically significant, detectable on CTA or MRA.

Synonyms

  • Arteria renalis

  • Kidney artery

  • Renal trunk

Function

  • Supplies oxygenated blood to the kidneys for filtration, excretion, and homeostasis

  • Maintains renal perfusion, regulating blood pressure and fluid balance through renal autoregulation

  • Provides segmental supply to the renal cortex and medulla, ensuring efficient nephron function

MRI Appearance

T1-weighted images:

  • Renal artery appears as a flow void (dark tubular structure) against perivascular fat

  • Useful for assessing vessel course

T2-weighted images:

  • Vessel lumen also shows signal void, but hyperintense perivascular edema can indicate pathology

STIR:

  • Suppresses fat, improving contrast between renal artery and surrounding tissue

  • Highlights perivascular edema or inflammation

T1 Fat-Saturated (Pre-contrast):

  • Vessel lumen may appear intermediate signal, standing out against suppressed fat planes

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Renal artery enhances brightly and homogeneously in arterial phase

  • Useful for detecting stenosis, aneurysm, or occlusion

MR Angiography (MRA):

  • Non-invasive gold standard for renal artery evaluation

  • Depicts origin, course, branching, and accessory arteries

  • Sensitive for renal artery stenosis, fibromuscular dysplasia, aneurysms, and pre-transplant mapping

CT Appearance

CT Pre-Contrast:

  • Artery appears as soft-tissue tubular density arising from aorta

  • Limited evaluation without contrast

CT Post-Contrast (Arterial Phase):

  • Renal artery opacifies brightly, showing course, branching, and relationship to renal hilum

  • Detects atherosclerotic plaques, stenosis, aneurysms, and dissections

CT Venous/Delayed Phase:

  • Helps assess renal perfusion and parenchymal enhancement patterns

  • Detects ischemic changes, infarcts, or delayed flow in stenosis

CT Angiography (CTA):

  • Gold standard for renal artery imaging

  • Provides detailed 3D reconstructions of main and accessory renal arteries

  • Essential for renal transplant donor evaluation, planning renal artery stenting, or embolization

  • Detects stenosis, aneurysms, dissections, and vascular malformations

CT images

renal artery CT axial image anatomy 1

CT images

renal artery CT axial image anatomy 2

CT images

renal artery CT axial image anatomy

MRI images

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

MRI images

renal artery MRI coronal image anatomy image -img-00000-00000_00001

MRI image

renal artery mri coronal imip image