Topics

Topic

design image
Apical segmental bronchus of right lung

The apical segmental bronchus of the right lung (B1) is one of the three segmental (tertiary) bronchi of the right upper lobe, arising from the right upper lobe bronchus just after its origin from the right main bronchus. It supplies the apical segment (S1) of the right upper lobe, located at the lung apex.

The bronchus courses upward and posteriorly, branching into subsegmental bronchi that ventilate the entire apical segment. Alongside the bronchus, the apical segmental artery (A1) and apical segmental vein (V1) form the broncho-vascular bundle. Together, these structures define the apical segment as a distinct functional unit of the lung, important in segmentectomy planning.

Synonyms

  • Right apical bronchus

  • B1 bronchus

  • Segmental bronchus to apical segment (S1)

Function

  • Supplies air to the apical segment (S1) of the right upper lobe

  • Contributes to effective ventilation of the lung apex

  • Landmark in bronchoscopy and thoracic surgery for identifying segmental anatomy

  • Critical in planning segmental resections for lung cancer, tuberculosis, or localized bronchiectasis

MRI Appearance

T1-weighted images:

  • Air-filled lumen appears as a signal void (black)

  • Bronchial wall shows a thin hypointense rim against hyperintense mediastinal fat

T2-weighted images:

  • Lumen remains a signal void

  • Adjacent vessels and fat planes provide contrast; mucus plugging or secretions may appear hyperintense

T2 TRUFISP (cardiac/respiratory-gated):

  • Clearly demonstrates the B1 bronchial lumen as a bright, air–tissue interface

  • Useful for dynamic visualization of bronchial patency and wall motion during respiration

STIR (Short Tau Inversion Recovery):

  • Fat suppression improves contrast of the bronchial wall against surrounding structures

  • Highlights edema or peribronchial inflammation as hyperintense signals

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • Normally the bronchus does not enhance (air-filled)

  • Bronchial wall enhancement may indicate inflammation, neoplasm, or vascularized pathology

MRI Non-Contrast Cardiac/Respiratory-Gated 3D Imaging:

  • Provides 3D reconstruction of the B1 bronchial course within the right upper lobe

  • Useful for mapping bronchial branching and segmental orientation in surgical planning when contrast is contraindicated

CT Appearance

High-Resolution CT (HRCT):

  • B1 bronchus seen as a round or oval air-filled lumen extending to the apical segment

  • Axial and coronal reconstructions show its course relative to the right upper lobe bronchus

  • Useful in detecting stenosis, obstruction, bronchiectasis, or neoplastic infiltration

CT Coronary Angiography / CT Pulmonary Angiography (extended views):

  • Contrast highlights accompanying A1 artery and V1 vein, helping define the broncho-vascular bundle of S1

  • 3D reconstructions enable precise segmental mapping for thoracic surgery

CT image

Apical segmental bronchus of right lung anatomy CT coronal image -img-00000-00000