Topics

Topic

design image
Anterior segmental artery of right lung

The anterior segmental artery of the right lung (A3) is one of the three main segmental branches of the right upper lobar pulmonary artery. It arises from the right superior lobar artery (a branch of the right pulmonary artery) and supplies the anterior bronchopulmonary segment (S3) of the right upper lobe.

Course: The A3 artery typically arises anteriorly from the right upper lobar artery, runs alongside the anterior segmental bronchus (B3), and descends forward into the anterior segment (S3) of the right upper lobe. The artery divides into smaller intrasegmental branches, which provide arterial blood to the alveoli and lung parenchyma of S3.

Relations: It courses in close proximity to the anterior segmental vein (V3) and bronchus (B3), forming the classic bronchovascular triad within the segment. Anatomical variations in origin or branching pattern are common and clinically significant in segmentectomy, lobectomy, and pulmonary embolism localization.

Synonyms

  • A3 artery

  • Right anterior segmental pulmonary artery

  • Segmental artery to S3 (right lung)

Function

  • Provides oxygen-poor arterial blood for gas exchange in the anterior segment (S3) of the right upper lobe

  • Plays a critical role in bronchopulmonary segmental perfusion

  • Serves as a landmark in pulmonary surgery and interventional radiology

Branches

  • Small intrasegmental branches supplying the anterior segment (S3) alveoli and parenchyma

MRI Appearance

T1-weighted images:

  • Appears as a signal void (black lumen) within the right upper lobe hilum

  • Adjacent mediastinal fat improves vessel conspicuity

T2-weighted images:

  • Blood flow appears as a signal void; abnormal thrombus or slow flow may appear intermediate-to-high signal

  • Helps in identifying pathology like segmental emboli

T2 TRUFISP (cardiac/respiratory-gated):

  • A3 artery visualized as a bright, continuous vascular channel with high contrast

  • Provides dynamic visualization of branching from the superior lobar artery

STIR (Short Tau Inversion Recovery):

  • Fat suppression enhances contrast of the artery against mediastinal and pulmonary fat

  • Highlights perivascular inflammation or edema as hyperintensity

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • A3 artery enhances homogeneously and brightly

  • Filling defects indicate segmental pulmonary embolism or stenosis

MRI Non-Contrast Cardiac-Gated 3D Imaging:

  • Demonstrates the origin and course of A3 into the anterior segment

  • Useful in patients with contrast contraindications and for preoperative mapping

MRA (Magnetic Resonance Angiography):

  • Contrast-enhanced MRA shows clear origin, segmental branching, and arborization

  • Useful in detecting segmental pulmonary embolism, vascular malformations, or congenital anomalies

CT Appearance

CT Pulmonary Angiography (CTPA):

  • A3 artery is opacified with contrast and seen branching anteriorly from the right superior lobar artery

  • Multiplanar and 3D reconstructions highlight its course toward the anterior segment (S3)

  • Gold standard for identifying segmental pulmonary emboli, stenosis, or anomalous branching

  • Helps thoracic surgeons in segmentectomy planning

CT image

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

MRI image

Anterior segmental artery of right lung mri axial image