Looking at the windpipe in CT chest Dr: Eid Elagamy Lecturer chest diseases Al-Azhar University Egypt

2. Dr: EiD M. ELaGamY
Lecturer Of Chest Diseases
Al-Azhar University

3. Normal Radiological
Tracheal Anatomy

4. Anatomical Landmarks Before Trachea
2- Aryepiglottic folds
1- Epiglottis
3- True vocal cords (asterisks)
thyroid cartilage (arrow)
4-Subglottic area (ovoid appearance)
Note Cricoid cartilage (arrow)

5. The trachea
from cricoid cartilage, just
below the true VC,
to the carina
10 –12
Midline in position
slightly to the right at the level of the aortic arch (This
displacement may be accentuated in older patients)

6. Tracheal wall
Visible (1- to 3-mm) soft-tissue density stripe,
demarcated internally by the air- filled tracheal
lumen and externally by the adjacent fat-density
of the mediastinum
The posterior wall is typically thinner
‘‘paper thin’’ (black arrow) than the
anterior and lateral walls (white arrow).
- Connected posteriorly by the membranous wall
of the trachea (No cartilage) and is supported by
trachealis ms
- These cartilage rings can calcify with old age &
those on long standing warfarin therapy
18-22 C-shaped tracheal cartilage

7. End Inspiration End Expiration
the tracheal lumen has narrowed slightly, with
anterior bowing of the posterior membranous
wall
Rounded lumen
Tracheal length is dynamic, changing with respiration and neck flexion and extension==>
carina can change in position up to 3 cm between inspiration and expiration
Also the lumen

8. Tracheal index
Coronal (transverse) diameter / sagittal (AP) diameter = 1

9. Tracheal
Dilatation
Abnormal Windpipes findings
Tracheal
Stenosis
Tracheal
Anomalies

10. Tracheal Anomalies

11. Tracheal bronchus
(Pig bronchus or Bronhus suis)
a bronchus originate directly from the lateral wall of the trachea
This bronchus may be
Rudimentary (it forms a blind-ending pouch) OR Accessory (Supernumerary) OR Displaced,
replacing the anatomical bronchus  Right upper lobe bronchus or apical segment (pig
bronchus or bronchus suis)

12. if this patient is intubated,  right upper
lobe atelectasis if the endotracheal tube
projects below the opening.
Incidental findings NO symptoms. However 
* Recurent infection and hemoptysis.
* In children, it is a recognized cause of recurrent right
upper lobe pneumonia or atelectasis and localized
bronchiectasis

13. Cardiac bronchus
Accessory bronchus which comes
off the medial aspect of the
bronchus intermedius.
(a true supernumerary bronchus)
This bronchus usually is blind ending but occasionally
supplies a rudimentary lobe of lung tissue
No signs or symptoms but  can be associated with
recurrent infection and hemoptysis.

14. CARDIAC BRONCHUS
Contrast-enhanced chest CT (lung window) of a 21-year-old man with
hemoptysis  an accessory cardiac bronchus demonstrates an air-filled tubular
structure (arrow) that arises from the medial wall of the bronchus intermedius
and courses toward the mediastinum.

15. Tracheal Dilatation

16. Tracheobronchomegaly = Tracheobronchiectasis
= Mounier-Kuhn disease
Tracheal
diverticulosis =
Irregular
corrugated
appearance of
trachea
Tracheal lumen
> 3 cm in size.
absence of
significant
pulmonary fibrosis
Bronchiectasis
(segmental and
subsegmental)
main bronchus
{Rt or Lt}lumen
> 2.4cm &2.3cm

17. Tracheobronchomegaly
- Dilated trachea and main bronchi (asterisk) with corrugated
appearance of the wall due to redundant mucosa
(arrowheads).
- Bilateral bronchiectasis
Presentation
Recurrent
pulmonary
infections

18. Traction Tracheomegaly
Tracheal
diverticulosis =
Irregular
corrugated
appearance of
trachea
Tracheal lumen
> 3 cm in size.
Significant
pulmonary
fibrosis
Bronchiectasis
(segmental and
subsegmental)
main bronchus
{Rt or Lt}lumen
> 2.4cm &2.3cm

19. Tracheal Narrowing (stenosis)
Long segment
Tracheal Stricture
Saber- Sheath Trachea
Tracheomalacia
Relapsing polychondritis
Trachebronchopathia
osteochondroplastica (TPO)
Amyloidosis
Rhinoscleroma
Wegener Granulomatosis
TB
Compression from outside
Short segment
Less common  amyloidosis,
Wegener's granulomatosis, tumors,
inflammatory bowel disease & airway
burns
Sarcoidosis
inflammatory bowel disease
Tumors

20. Saber sheath trachea
NORMAL Tracheal index
= coronal / sagittal diameter = 1
Tracheal index <0.6
Sagittal : Coronal ratio >1.5 (??2)
Saber-sheath trachea
Acquired intrathoracic tracheal deformity  Marked ↓ coronal
diameter and ↑ sagittal diameter ; measured 1 cm above the
superior aspect of the aortic arch.
strongly associated with COPD. ??correlates with severity of airway
obstruction??
 fixed deformity While tracheomalacia  not fixed

21. Weakness of the airway walls (posterior
tracheal membranous wall or supporting
cartilage)  excessive expiratory
collapse of the airway lumen (≥ 50
reduction in AP diameter ) The
posterior tracheal wall bulges into the
tracheal lumen with forced expiration or
coughing.
Trachebronchomalacia
End-inspiratory
Normal
Dynamic expiratory
Tracheobronchomalacia
The tracheal collapse of 50% can
be seen in healthy persons, and
hence the cutoff of 70% has been
suggested to avoid false positives

22. Tracheomalacia
Tracheomalacia refers to the trachea being softer than norma
breathes out or coughs the calibre of the trachea gets smalle
chest showing an abnormal “D” or kidney shape to t he trache
the trachea is round.
End-inspiratory: trachea is normal. Dynamic expiratory : circumferential
narrowing of tracheal lumen.
excessive expiratory collapse
(abnormal “D” or kidney
excessive expiratory collapse
(semilunate or crescentic )

23. excessive expiratory collapse =
expiratory ‘‘frown-like’’ configuration
(Frown sign)
Specific sign of TBM

25. accentuation of coronal (transverse)
diameter with a relative narrowing of
sagittal (AP) diameter
Coronal : Sagittal ratio >1
= Lunate trachea
Dynamic expiratory : near complete
expiratory tracheal collapse (arrow)
end-inspiratory: elongated coronal
diameter of trachea with relative
decrease in sagittal dimension
Computed tomography (CT) may reveal a semilunate,
discoid, or crescentic trachea when viewed in cross
section

26. Relapsing Polychondritis
autoimmune disorder  inflammation and destruction of cartilaginous structures
(ears, nose, joints, and laryngotracheobronchial and Aorta ) the last 2 are fatal
Airway involvement in relapsing
polychondritis is a poor prognostic sign
and is the leading cause of death
- Fixed narrowing of lumen
- smooth diffuse thickening of the anterior and lateral walls
of the trachea (arrows)
- sparing of the posterior membranous portion (arrowhead).

27. Smooth Calcified thickening of the anterior and lateral walls of the trachea and
mainstem bronchi that spares the posterior wall with lumen narrowing
= relapsing polychondritis.

28. Tracheobronchopathia
osteochondroplastica (TPO) Benign disease
asymptomatic (often cough, shortness
of breath, and hemoptysis )
discovered incidentally at imaging.
characterized by the presence of
osseous and cartilaginous submucosal
nodules connected to tracheal cartilage
Recognition of TPO allow exclusion of
the other causes of nodular tracheal
wall thickening
CT:
Calcified nodular opacities that protrude into the airway lumen resulting in 
Diffuse irregular tracheal narrowing which spares the posterior membranous portion
of the airway wall is spared.
((Calcification is typically present BUT not all lesions are calcified))

30. Post-
intubation/tracheostomy
Tracheal Stenosis or
Stricture
Typical stenosis on the coronal image gives an
“hour-glass” shape to trachea due to focal
involvement.
Focal (0.2 - 3.5 cm) stricture (Stenosis or web) at the site of the tube cuff (2.5–5 cm from the vocal cord)
 Very thin cut of CT to avoid under or overestimation
CT with coronal and sagittal reconstructions has high
accuracy in assessment of location and severity

31. Goiter  extrinsic mass effect on
the trachea with resultant luminal
narrowing.
Tracheal Stenosis due to
compression from
outside

32. Tracheal thickening

33. CT features of tracheal tumors
 Nonspecific
Tracheal Tumors

34. Benign tumors
Well-circumscribed
polypoid intraluminal mass
Rounded
Smooth
< 2cm in diameter
limited by the tracheal cartilage
Hamartoma of the left main bronchus
- Lipoma  Fat
- Hamartoma Fat + Calcification

35. Malignant tumors
Primary as
Squamous cell carcinoma
And adenoid cystic carcinoma
CT  mass or circumferential thickening of tracheal
wall with irregular narrowing of the lumen
Secondary as
direct invasion from thyroid, esophagus, larynx, lung
Hematogenous mets mostly from melanoma , breast ,
genitourinary
CT  single or multiple polypoid intraluminal mass