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Left renal artery

The left renal artery is a major branch of the abdominal aorta supplying the left kidney. It arises just below the origin of the superior mesenteric artery at the level of L1–L2 vertebrae. The artery is longer than the right renal artery, as the aorta lies slightly to the left of the midline. It courses laterally and posterior to the left renal vein before entering the renal hilum, where it divides into segmental branches.

The left renal artery is of great clinical significance in renal hypertension (renal artery stenosis), kidney transplantation, vascular anomalies, and trauma.

Synonyms

  • Left main renal artery

  • Aortic renal branch (left)

Origin, Course, and Relations

  • Origin: Arises from the lateral wall of the abdominal aorta at L1–L2, slightly below the superior mesenteric artery

  • Course: Runs horizontally and laterally toward the left kidney

  • Relations:

    • Anteriorly: Left renal vein, body of pancreas

    • Posteriorly: Left crus of diaphragm, psoas major muscle

    • Laterally: Left kidney hilum

    • Superiorly: Adrenal gland

    • Inferiorly: Left gonadal vessels

Function

  • Supplies arterial blood to the left kidney, adrenal gland (via superior adrenal branches), and ureter (via proximal ureteric branches)

  • Maintains renal perfusion and contributes to systemic blood pressure regulation

MRI and CT Appearance

T1-weighted images:

  • Left renal artery appears as a flow void (signal loss) due to fast-flowing blood

  • Walls not well visualized unless thrombosed or calcified

T2-weighted images:

  • Artery appears as a flow void (dark linear/tubular structure) against surrounding soft tissues

  • Slow or turbulent flow may cause mild intraluminal hyperintensity

MRA (Magnetic Resonance Angiography):

  • Gadolinium-enhanced MRA: artery appears as a bright, high-signal tubular structure from its aortic origin to renal hilum

  • Useful for assessing stenosis, aneurysm, or variant anatomy

  • Non-contrast TOF (time-of-flight) MRA: artery appears bright due to inflow effect

T1 Fat-Sat Post-Gadolinium:

  • Vessel lumen shows strong enhancement

  • Vessel wall may enhance in cases of vasculitis or inflammatory changes

CTA (CT Angiography):

  • Lumen opacified with contrast: bright, high-attenuation tubular structure

  • Provides high-resolution 3D visualization of artery and branches

  • Detects stenosis, aneurysms, accessory renal arteries

CT Post-Contrast (venous phase):

  • Artery remains contrast-enhanced but less bright than in arterial phase

  • Visualized in relation to renal vein and parenchymal enhancement

  • Helps assess delayed perfusion abnormalities or collateral circulation

MRI image

Left Renal Artery AXIAL

MRI image

left renal artery