Contouring of CTV lymph nodes in NSCLC (Part I)

1. Contouring of CTV_Lymph nodes in NSCLC (Part I)
Mohammed Fathy Bayomy, MSc, MD
Lecturer
Clinical Oncology & Nuclear Medicine
Faculty of Medicine
Zagazig University

2. Rouvière map (1967)

3. Thoracic Lymph Nodes
Nodes Details
Internal thoracic lymph
nodes
Form two chains, on either side of posterior aspect of sternum,
from xiphoid process to fist rib, along course of internal thoracic
vessels.
Intercostal lymph nodes
(paravertebral nodes)
Located in posterior portion of intercostal spaces, near heads of
ribs.
Diaphragmatic lymph
nodes
Located in diaphragmatic convexity, they are grouped in loose
cellular tissue at base of pericardium. They are divided into:-
Anterior group: behind xiphoid process.
Right lateral group: at level of diaphragmatic orifice of IVC.
Left lateral group: near phrenic nerve.
Posterior group: behind diaphragmatic crura.
1- Parietal nodes

4. Thoracic Lymph Nodes (Cont.,)
2- Visceral (Pulmonary) nodes (Rouvière classification)
Nodes Details
Anterior mediastinal
(prevascular) nodes
They run between sternum & heart, anterior to great vessels.
Posterior mediastinal
(juxtaesophageal)
nodes
Located between posterior aspect of pericardium & vertebral
column. They are divided into pre- and retroesophageal nodes.
Peritracheobronchial
lymph nodes
Located around trachea & main bronchi. Thy are divided into:
– Lymph nodes of pulmonary pedicle: located between origin of
bronchus & mediastinal pleural reflection
– Subcarinal nodes: situated below carina
– Peritracheal nodes: located on anterior & lateral aspects of trachea
& a few posteriorly.
Intrapulmonary lymph
nodes
Thy follow bronchial divisions in lungs.

5. Thoracic Lymph Nodes (Cont.,)

6. Naruke map (1978)

7. Station Anatomical definition
1- Superior mediastinal lymph nodes Located at upper third of trachea within thorax
2- Paratracheal lymph nodes Corresponding to a level between stations 1 & 4, & situated along lateral sides of trachea
3- Pretracheal, retrotracheal, or posterior
mediastinal, & anterior mediastinal lymph nodes
4- Tracheobronchial nodes Lateral portion of junction between trachea & main bronchi (on right side they are
located at level of azygos vein & on left side they are adjacent to subaortic lymph nodes).
5- Subaortic lymph nodes (Botallo's nodes)
6- Para-aortic lymph nodes
7- Subcarinal lymph nodes
8- Paraesophageal nodes (below carina)
9- Pulmonary ligament lymph nodes
10- Hilar lymph nodes
11- Interlobar lymph nodes Right interlobar nodes are classified, if necessary, into superior & inferior
12- Lobar lymph nodes
13- Segmental lymph nodes
14- Subsegmental lymph nodes

9. American Thoracic Society
(ATS) map (1993)

10. Nodal Station Definitions/nodal staging
1 R/L (Supraclavicular) Supraclavicular or scalene nodes (always N3).
2 R/L (Right/Left Upper paratracheal
nodes)
To right/left of midline of trachea. between apex of lung & superior margin of aortic arch (N2 if
ipsilateral to tumour otherwise N3)
4R (Right lower paratracheal nodes) To right of midline of trachea, between superior margin of aortic arch & superior margin of azygos vein
(N2 if ipsilateral tumour otherwise N3)
4L (Left lower paratracheal nodes) To left of midline of trachea between top of aortic arch & level of carina, medial
to ligamentum arteriosum (N2 if ipsilateral tumour otherwise N3).
5 (Aortopulmonary nodes, subaortic
& para-aortic )
Lateral to ligamentum arteriosum or aorta or left pulmonary artery proximal to first branch of left
pulmonary artery (N2 if ipsilateral tumour otherwise N3).
6 (Anterior mediastinal nodes) Anterior to ascending aorta or innominate artery (N2 if ipsilateral tumour otherwise N3).
7 (Subcarinal nodes) Caudal to carina but not associated with lower lobe bronchi or arteries within lung (always N2).
8 (Paraoesophageal nodes) Surrounding oesophagus dorsal to posterior wall of trachea, includes nodes relating to descending
aorta + nodes within right or left pulmonary ligament (N2 if ipsilateral tumour otherwise N3).
10R (Right tracheo-bronchial nodes) To right of midline of trachea, from level of cephalic border of azygos vein to origin of right upper lobe
bronchus (N1 if ipsilateral tumour otherwise N3)
10L (Left tracheo-bronchial nodes) To left of midline of trachea between carina & left upper lobe bronchus, medial to ligamentum
arteriosum (N2 if ipsilateral tumour otherwise N3).
11R/L (Intrapulmonary nodes) Lying within lung distal to upper lobe bronchus (N1 if ipsilateral tumour otherwise N3).
14 (Superior diaphragmatic nodes) Adjacent to pericardium within 2 cm of diaphragm (N2 if ipsilateral tumour otherwise N3).

12. Mountain & Dresler (M-D) map (1997)

13. Nodal Station Anatomical landmark
1 Highest mediastinal nodes Above a horizontal line at upper rim of brachiocephalic (left innominate) vein where it ascends to
left, crossing in front of trachea at its midline
2 Upper paratracheal nodes Above a horizontal line drawn tangential to upper margin of aortic arch & below inferior boundary of
No. 1 nodes.
3 Prevascular & retrotracheal nodes May be designated 3A and 3P. Midline nodes are considered to be ipsilateral.
4 Lower paratracheal nodes Right lower paratracheal nodes: lie to right of midline of trachea between a horizontal line drawn
tangential to upper margin of aortic arch & line extending across right main bronchus at upper
margin of upper lobe bronchus, & contained within mediastinal pleural envelope.
Left lower paratracheal nodes: lie to left of midline of trachea between horizontal line drawn
tangential to upper margin of aortic arch & line extending across left main bronchus at level of upper
margin of left upper lobe bronchus, medial to ligamentum arteriosum & contained within
mediastinal pleural envelope.
4s (superior) subset: defined by a horizontal line extending across the trachea & drawn tangential to
cephalic border of azygos vein.
4i (inferior) subset: defined by lower boundary of No. 4s & lower boundary of No. 4.
5 Subaortic (aorta-pulmonary window) Lateral to ligamentum arteriosum or aorta or left pulmonary artery & proximal to first branch of left
pulmonary artery & lie within mediastinal pleural envelope.
6 Para-aortic nodes (ascending aorta or
phrenic)
Anterior & lateral to ascending aorta & aortic arch or innominate artery, beneath a line tangential to
upper margin of the aortic arch.
7 Subcarinal nodes Caudal to carina of trachea, but not associated with lower lobe bronchi or arteries within lung.
8 Paraesophageal nodes (below carina) Adjacent to wall of esophagus & to right or left of midline, excluding subcarinal nodes.
9 Pulmonary ligament nodes Within pulmonary ligament, including those in posterior wall & lower part of inferior pulmonary vein

14. Nodal Station Anatomical landmark
10 Hilar nodes Proximal lobar nodes, distal to mediastinal pleural reflection & nodes adjacent to bronchus
intermedius on right; radiographically, hilar shadow may be created by enlargement of both hilar and
interlobar nodes.
11 Interlobar nodes Between lobar bronchi.
12 Lobar nodes Adjacent to distal lobar bronchi.
13 Segmental nodes Adjacent to segmental bronchi.
14 Subsegmental nodes Around subsegmental bronchi.

15. University of Michigan
(Chapet map 2005)

17. Stations 1–2R & 1–2L: highest mediastinal & upper paratracheal nodes
Border Definition
Superiorly Upper limit of sternal notch.
Inferiorly Just superior to aortic arch.
Medially 1-2R and 1-2L are separated by
midline of trachea.
Laterally Pleural envelope.
Anteriorly Posterior to vessels (right subclavian
vein, left brachiocephalic vein, right
brachiocephalic vein, left subclavian
artery, left common carotid artery,
brachiocephalic trunk).
Posteriorly Imaginary horizontal line extending
along posterior wall of trachea.

18. Stations 3A: prevascular nodes or retrosternal nodes
Station 3A includes left brachiocephalic vein in its mediastinal
section until superior vena cava.
Border Definition
Superiorly Upper limit of sternal notch.
Inferiorly Level of carina.
Laterally Pleural envelope.
Anteriorly Sternum, clavicular heads, ribs.
Posteriorly Superiorly: anterior border of
stations 1–2 but excludes left
subclavian artery, left common
carotid artery, brachiocephalic trunk
Inferiorly: in contact with station 6
on left & anterior border of SVC on
right.

19. Stations 3A: prevascular nodes or retrosternal nodes (Cont.,)
Border Definition
Superiorly Upper limit of sternal notch.
Inferiorly Level of carina.
Laterally Pleural envelope.
Anteriorly Sternum, clavicular heads, ribs.
Posteriorly Superiorly: anterior border of
stations 1–2 but excludes left
subclavian artery, left common
carotid artery, brachiocephalic trunk
Inferiorly: in contact with station 6
on left & anterior border of SVC on
right.

20. Stations 3P: retrotracheal nodes
Border Definition
Superiorly Upper limit of sternum.
Inferiorly Level of carina.
Right limit Air–soft-tissue interface.
Left limit Superiorly: air–soft-tissue interface.
Inferiorly: aorta.
Anteriorly Superiorly: posterior aspect of
Stations 1–2.
Inferiorly: posterior aspect of
Stations 4R & 4L.
Kept posterior to trachea, which is
defined by imaginary horizontal
line running along posterior wall of
trachea.
Posteriorly Along anterior & lateral borders of
vertebral body until imaginary
horizontal line running 1 cm
posteriorly to anterior border of
vertebral body.

21. Stations 3P: retrotracheal nodes (Cont.,)
Border Definition
Superiorly Upper limit of sternum.
Inferiorly Level of carina.
Right limit Air–soft-tissue interface.
Left limit Superiorly: air–soft-tissue interface.
Inferiorly: aorta.
Anteriorly Superiorly: posterior aspect of
Stations 1–2.
Inferiorly: posterior aspect of
Stations 4R & 4L.
Kept posterior to trachea, which is
defined by imaginary horizontal
line running along posterior wall of
trachea.
Posteriorly Along anterior & lateral borders of
vertebral body until imaginary
horizontal line running 1 cm
posteriorly to anterior border of
vertebral body.

22. Stations 4R: right lower paratracheal nodes
Border Definition
Superiorly Top of aortic arch.
Inferiorly Upper lobe bronchus or where right
pulmonary artery crosses midline of
mediastinum.
Left limit Midline of trachea.
Right limit Upper part: pleural envelope
Intermediate section: medial to SVC & arch
of azygos vein
Caudal part: right upper lobe pulmonary vein
Anteriorly Limited most superiorly by right
brachiocephalic vein followed by SVC & arch
or ascending section of aorta. In between
SVC & aorta, extends halfway between two
vessels where it will contact Station 3A or 6.
Posteriorly Imaginary horizontal line running along
posterior wall of trachea then right main
stem bronchus

23. Stations 4R: right lower paratracheal nodes (Cont.,)
Border Definition
Superiorly Top of aortic arch.
Inferiorly Upper lobe bronchus or where right
pulmonary artery crosses midline of
mediastinum.
Left limit Midline of trachea.
Right limit Upper part: pleural envelope
Intermediate section: medial to SVC & arch
of azygos vein
Caudal part: right upper lobe pulmonary vein
Anteriorly Limited most superiorly by right
brachiocephalic vein followed by SVC & arch
or ascending section of aorta. In between
SVC & aorta, extends halfway between two
vessels where it will contact Station 3A or 6.
Posteriorly Imaginary horizontal line running along
posterior wall of trachea then right main
stem bronchus

24. Stations 4L: left lower paratracheal nodes
Border Definition
Superiorly Top of aortic arch.
Inferiorly Upper lobe bronchus (disappearance of the
space bordered by left main bronchus, & left
& right pulmonary arteries).
Left limit Upper section: aortic arch.
Intermediate section: midline between
ascending & descending aorta.
Lower section: pulmonary trunk &/or left
pulmonary artery.
Right limit Vertical line through middle of trachea,
except more inferiorly, where it is
limited by right pulmonary artery & Station 7
Anteriorly Great vessels or aorta.
Posteriorly Imaginary horizontal line running along
posterior wall of trachea or anterior aspect
of left main bronchus.

25. Stations 4L: left lower paratracheal nodes (cont.,)
Border Definition
Superiorly Top of aortic arch.
Inferiorly Upper lobe bronchus (disappearance of the
space bordered by left main bronchus, & left
& right pulmonary arteries).
Left limit Upper section: aortic arch.
Intermediate section: midline between
ascending & descending aorta.
Lower section: pulmonary trunk &/or left
pulmonary artery.
Right limit Vertical line through middle of trachea,
except more inferiorly, where it is
limited by right pulmonary artery & Station 7
Anteriorly Great vessels or aorta.
Posteriorly Imaginary horizontal line running along
posterior wall of trachea or anterior aspect
of left main bronchus.

26. Stations 4L: left lower paratracheal nodes (cont.,)
Border Definition
Superiorly Top of aortic arch.
Inferiorly Upper lobe bronchus (disappearance of the
space bordered by left main bronchus, & left
& right pulmonary arteries).
Left limit Upper section: aortic arch.
Intermediate section: midline between
ascending & descending aorta.
Lower section: pulmonary trunk &/or left
pulmonary artery.
Right limit Vertical line through middle of trachea,
except more inferiorly, where it is
limited by right pulmonary artery & Station 7
Anteriorly Great vessels or aorta.
Posteriorly Imaginary horizontal line running along
posterior wall of trachea or anterior aspect
of left main bronchus.

27. Stations 5: subaortic (aortic–pulmonary window) nodes
Border Definition
Superiorly Inferior aspect aortic arch.
Inferiorly Lowest image in which right pulmonary
artery is maximally visualized
Left limit Pleural envelope.
Right limit Boundary of Station 4L and pulmonary trunk,
left pulmonary artery.
Anteriorly Extending to midpoint of ascending aorta or
visible soft tissue.
Posteriorly Anterior aspect of descending
aorta, left lateral aspect the pulmonary
trunk, upper lobe pulmonary veins and/or
left pulmonary artery.

28. Stations 5: subaortic (aortic–pulmonary window) nodes (cont.,)
Border Definition
Superiorly Inferior aspect aortic arch.
Inferiorly Lowest image in which right pulmonary
artery is maximally visualized
Left limit Pleural envelope.
Right limit Boundary of Station 4L and pulmonary trunk,
left pulmonary artery.
Anteriorly Extending to midpoint of ascending aorta or
visible soft tissue.
Posteriorly Anterior aspect of descending
aorta, left lateral aspect the pulmonary
trunk, upper lobe pulmonary veins and/or
left pulmonary artery.

29. Stations 6: paraaortic nodes or anterior aortic nodes
Border Definition
Superiorly Top of aortic arch.
Inferiorly Upper lobe bronchus (disappearance of the
space bordered by left main bronchus, & left
& right pulmonary arteries).
Anteriorly &
laterally
Extends 1 cm around ascending aorta &
aortic arch.
Posteriorly Anterior & lateral walls of ascending aorta,
aortic arch & anterior aspect of medial wall
of pulmonary trunk until station 5.

30. Stations 6: paraaortic nodes or anterior aortic nodes (cont.,)
Border Definition
Superiorly Top of aortic arch.
Inferiorly Upper lobe bronchus (disappearance of the
space bordered by left main bronchus, & left
& right pulmonary arteries).
Anteriorly &
laterally
Extends 1 cm around ascending aorta &
aortic arch.
Posteriorly Anterior & lateral walls of ascending aorta,
aortic arch & anterior aspect of medial wall
of pulmonary trunk until station 5.

31. Stations 7: subcarinal nodes
Border Definition
Superiorly At carina.
Inferiorly Origin of right middle lobe bronchus.
Laterally Space between right main & left main
bronchi.
Anteriorly Station 4R, Station 4L, right pulmonary
artery, &/or left superior pulmonary vein.
Posteriorly Station 8 & does not extend past
posterior wall of main bronchi.

32. Stations 8: paraesophageal nodes
Border Definition
Superiorly Level of carina, abuts station 3P.
Inferiorly Gastroesophageal junction.
Laterally Pleural envelope & abuts descending aorta
on left (limited to soft tissue surrounding
esophagus).
Anteriorly Superiorly: station 7 & left main stem
bronchus.
Inferiorly: heart.
Posteriorly Abuts descending aorta &anterior aspect of
vertebral body until imaginary horizontal line
running 1 cm posterior to anterior border of
vertebral body.

33. Stations 10-11R: right hilar nodes
Border Definition
Superiorly Division of right upper lobe bronchus into
segmental branches.
Inferiorly Origin of superior segmental bronchus of
right lower lobe.
Laterally Air–tissue interface when CT slice is
displayed in mediastinal windows.
Medially Imaginary line drawn between lateral border
of SVC & middle of vertebral body.
Anteriorly &
posteriorly
Air–tissue interface when the CT slice is
displayed in mediastinal window, with
inclusion of main bronchus, lobar bronchi,
vessels in hilum.
Stations 10 & 11 were grouped together, because these
nodes are included in radiographic hilar shadow, and it is
difficult to differentiate them on axial CT images. We
recommend use of a lung window width of 850 & level of -
750 to identify the segmental bronchus as anterior, posterior,
and lateral limits of Stations 10–11. Mediastinal CT settings
were used to define medial border of hilum.

34. Stations 10-11L: left hilar nodes
Border Definition
Superiorly Bifurcation of upper lobar bronchus
into segmental bronchi.
Inferiorly Point at which left lower lobe
bronchus branches into segments.
Laterally Air–tissue interface should be used but
segmental bronchi must not be included in
this volume.
Medially Imaginary line drawn between lateral border
of pulmonary trunk & lateral border of
descending aorta.
Anteriorly Limited by posterior border of left
pulmonary artery.
Posteriorly Limited by posterior border of left
lower pulmonary artery.

35. International Association
for the Study of
Lung Cancer
(IASLC) map (2009)

36. Map of Stations

37. Grouping of lymph node stations into “7 Zones”.
Nodal Zone Lymph node station
1- Supraclavicular zone Low cervical, supraclavicular, sternal notch (1R – 1L)
2- Upper zone Upper paratracheal (2R – 2L)
Prevascular (3a)
Retrotracheal (3p)
Lower paratracheal (4R – 4L)
3- Aortopulmonary
(AP) zone
Subaortic (aortopulmonary window - 5)
Para-aortic (ascending aorta or phrenic nerve - 6)
4- Subcarinal zone Subcarinal (7)
5- Lower zone Paraesophageal (8R – 8L)
Pulmonary ligament (9R – 9L)
6- Hilar zone Hilar (10R – 10L – 10L*)
Interlobar (11), Superior (11s) Inferior (11i)
7- Peripheral zone Lobar (12R – 12L)
Segmental (13R – 13L)
Subsegmental (14R – 14L)

38. Grouping of lymph node stations into “7 Zones”.
Nodal Zone Lymph node station
1- Supraclavicular zone Low cervical, supraclavicular, sternal notch (1R – 1L)
2- Upper zone Upper paratracheal (2R – 2L)
Prevascular (3a)
Retrotracheal (3p)
Lower paratracheal (4R – 4L)
3- Aortopulmonary
(AP) zone
Subaortic (aortopulmonary window - 5)
Para-aortic (ascending aorta or phrenic nerve - 6)
4- Subcarinal zone Subcarinal (7)
5- Lower zone Paraesophageal (8R – 8L)
Pulmonary ligament (9R – 9L)
6- Hilar zone Hilar (10R – 10L – 10L*)
Interlobar (11), Superior (11s) Inferior (11i)
7- Peripheral zone Lobar (12R – 12L)
Segmental (13R – 13L)
Subsegmental (14R – 14L)

46. Supraclavicular zone: station 1

48. Upper zone: station 2R, 2L, 3a, 3p, 4R, 4L

53. AP zone: stations 5 & 6

55. Subcarinal zone: station 7

57. Lower zone: station 8 & 9

59. Hilar/interlobar zone: station 10 & 11

60. Hilar/interlobar zone: station 10 & 11

61. Peripheral zone: station 12, 13, and 14
• These nodes are intrapulmonary &
for staging purposes are to be
differentiated from intrapulmonary
metastasis.
• Differentiation affects staging as an
intrapulmonary metastasis in same
lobe as primary tumour would be
T3 cancer while station 12, 13, or
14 nodes would be N1 disease.
• Nodes are usually
peribronchovasular often at areas
of bronchial branching.