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Apical segmental artery of right lung

The apical segmental artery of the right lung (A1) is the superior-most segmental branch of the right superior lobar pulmonary artery, supplying the apical bronchopulmonary segment (S1) of the right upper lobe.

It typically arises from the right superior lobar artery shortly after its division from the right pulmonary artery (RPA) and courses superiorly and posteriorly toward the lung apex. The A1 artery runs in close relation to the apical segmental bronchus (B1) and is accompanied by tributaries of the apical segmental vein (V1).

Its anatomical orientation makes it critical in thoracic surgery, particularly in segmentectomy and lobectomy procedures, as well as in angiographic evaluation of pulmonary circulation. Variations in its branching pattern can occur, sometimes sharing a common trunk with the posterior segmental artery (A2) or the anterior segmental artery (A3).

Synonyms

  • A1 artery

  • Apical branch of right superior lobar artery

  • Arteria segmentalis apicalis dextra

Function

  • Supplies oxygenated blood to the apical bronchopulmonary segment (S1) of the right upper lobe

  • Contributes to perfusion of apical alveoli for gas exchange

  • Serves as an important anatomical landmark in pulmonary segmentectomy

Branches

  • Smaller intrasegmental branches that follow subsegmental bronchi (B1 sub-branches) to perfuse apical lung parenchyma

MRI Appearance

T1-weighted images:

  • A1 appears as a signal void (black lumen) due to arterial flow

  • Vessel wall is hypointense; surrounding parenchyma provides contrast

T2-weighted images:

  • Flow void persists, but edema or compression may distort margins

  • High signal within lumen may indicate slow flow or thrombus

T2 TRUFISP (cardiac/respiratory-gated):

  • A1 artery seen as a bright vascular lumen with sharp contrast to lung parenchyma

  • Provides cine-like visualization of pulsatility and branching pattern

STIR:

  • Fat suppression improves visualization of the artery at the hilum

  • Highlights perivascular inflammatory or edematous changes as hyperintense zones

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • A1 enhances brightly and homogeneously

  • Filling defects indicate embolism, stenosis, or anomalous branching

MRI Non-Contrast Cardiac-Gated 3D Imaging:

  • Accurately depicts 3D anatomy of A1 artery and its relation to B1 bronchus

  • Useful in mapping segmental vascular anatomy before surgery or ablation

  • Valuable in patients unable to receive contrast

MRA (Magnetic Resonance Angiography):

  • Contrast-enhanced MRA shows A1 artery origin, course, and branching

  • Identifies vascular malformations, stenosis, or arteriovenous shunts

CT Appearance

CT Pulmonary Angiography (CTA):

  • Contrast opacifies the A1 artery and intrasegmental branches

  • Multiplanar and 3D reconstructions show its relation to the apical bronchus and veins

  • Gold standard for detecting pulmonary embolism, segmental stenosis, aneurysm, or anomalies

  • Essential for surgical planning in apical segmentectomy

CT image

Apical segmental artery of right lung anatomy ct axial image -img-00000-00000

MRI image

Apical segmental artery of left lung mri axial image