1. Chest X-Ray Interpretation for the Internist
Theresa Cuoco, MD
August 2, 2012

2. Disclaimer: I am NOT a radiologist!

3. Why do we need to know?
To direct care while awaiting an “official read”
Low level radiation for the patient
Easily available and noninvasive
Relatively inexpensive
We need to have a basic knowledge of CXR interpretation

4. Objectives Basics of technique
Initial basics and type of film
Identification of structures on a “normal” CXR
Alveolar vs interstitial, lobar anatomy, silhouette sign, air bronchograms, and patterns of lung disease
The mediastinum, pleura, and heart
Mediastinum will cover anterior middle and posterior structures
Lungs: will cover lobar anatomy, silhouette sign, air bronchograms and patterns of lung disease
Also spend some time discussing the pleura
Airways, bones and breasts, cardiac and costophrenic diaphragm, edges and extrathoracic, fields lung fields and failure

5. The Basics (“the TIONS”)
IdentificaTION
InspiraTION
PenetraTION
RotaTION
Identification: make sure its your patient on particular day; male vs female; foreign objects
Inspiration: well inspired film you should be able to count 8 ribs…otherwise crowded lung markins, high diaphragms etc EXP film – to detect focal air trapping, may accentuate a PTX
Penetration- if not properly penetrated, xray can exaggerate or obliterate important findings…. You should be able to see thoracic vertebrae behind heart
Rotation: equal distance from vertebral spines to medical ends of clavicles.

6. Inspiration vs. Expiration
Indications for expiratory film – to look for air trapping – In a film that would normally get whiter with expiration, the area would remain inflated and black; also to detect a pneumothorax
Indications for an expiratory film?
-To detect pneumothorax or look for air trapping
(would remain inflated and black instead of white)

7. Penetration A B Heavy light exposure causes the film to be black (A)
Little light exposure causes the film to be white (B)

8. Rotation

9. Technique PA and lateral AP Which is preferred and why?
Less magnification, sharper images
Better inspiratory effort, pleural fluid and air easier to see
Lateral film – left side of chest against x-ray cassette
Decubitus films
PA and lateral – x-ray tube is 6 feet from film or detector
1. Less magnification 2. sharper images 3. better inspiratory effort and view of lungs 4. pleural fluid and air easier to see on erect film

10. Which is which? Crisp CPA More magnification, dull images,
poor inspiratory effort

11. Normal Anatomy CPA Left diaphragm Heart Aortic knob Trachea F. Hilum
A costophrenic angle B left diaphragm C heart D aortic knob E trachea F hilum G carina H stomach bubble J ascending aorta
CPA
Left diaphragm
Heart
Aortic knob
Trachea
F. Hilum
G. Carina
H. Stomach bubble
J. Ascending aorta

12. The Normal Chest X-Ray Gas in splenic flexure B. CPA C. Heart
A gas in splenic flexure B costophrenic angle C heart D descending aorta E trachea F carina G hilum H aortic knob J ascending aorta K right diaphragm
The left hilum is slightly higher than the right – this is normal
Gas in splenic flexure B. CPA C. Heart
D. Descending aorta E. Trachea F. Carina
G. Hilum H. Aortic knob J. Ascending aorta K. Right diaphragm
The left hilum is slightly higher than the right – this is normal

13. Alveolar vs. Interstitial
Alveolar = air sacs
Radiolucent
Can contain blood, mucous, tumor, or edema (“airless lung”)
Interstitial = vessels, lymphatics, bronchi, and connective tissue
Radiodense
Interstitial disease: prominent lung markings with aerated lungs
Interstitium is essentially branching pulmonary arteries

14. Lobar Anatomy Right: Upper, middle, lower Left: Upper and lower
Anterior
Posterior
The fissure has to be parallel to the x ray beam for it to be visible on the film – therefore the oblique (major) fissures are not visible on the normal frontal projection
The fissure has to be parallel to the x ray beam for it to be seen on the film.
The oblique (major) fissures are not visible on the normal frontal projection

15. Lobar Anatomy – Lateral Views
Right
Left

16. The Silhouette Sign There are 4 basic radiographic densities
Gas, fat, soft tissue (water), and metal (bone)
Anatomic structures are recognized on x-ray by their density differences
Two substances of the same density in direct contact can’t be differentiated
Loss of the normal radiologic silhouette (contour) is called the “silhouette sign”

17. Localizing Lesions Where is the silhouette sign?
RML Pneumonia with obscured right heart border
Where is the silhouette sign?
Obscured right heart border
Right middle lobe infiltrate

18. Localizing Lesions You can still see right heart border
Right lower lobe infiltrate
You can still see right heart border

19. Localizing Lesions A: lost heart border = lingular
A Left lingular infiltrate B left lower lobe infiltrate
A: lost heart border = lingular
B: lost hemidiaphragm = LLL

20. Localizing Lesions A: loss of right hilum; B: lost aortic knob
A. Right upper lobe infiltrate B left upper lobe patchy infiltrate
A: loss of right hilum;
ascending aorta
B: lost aortic knob

21. Localizing Lesions: Review
Ascending aorta, upper R heart border = RUL
R heart border = RML
R anterior hemidiaphragm = RLL
Aortic knob = LUL
L heart border = lingula
L anterior hemidiaphragm or descending aorta = LLL
If the heart is positioned slightly to the left, the right heart border may overlap the spine

22. The Air Bronchogram
When lung is consolidated and bronchi contain air, the dense lung delineates the air-filled bronchi
Visualization of air in the intrapulmonary bronchi is called the “air bronchogram sign”
Abnormal finding
Can be seen in:
PNA, edema, infarction
Chronic lung lesions

23. NO Air Bronchograms…
In pneumonia if bronchi are filled with secretions
If cancer obstructs a bronchus
Interstitial fibrosis
Asthma/emphysema (hyperinflation)

24. What do you see?
Left lung consolidated and collapsed – trachea shifted toward that side; heart shifted left

25. Lung and Lobar Collapse
When a whole lung collapses, the trachea deviates TOWARD the side of collapse (due to volume loss)
Left lung consolidated and collapsed

26. Fissures Formed by 2 visceral pleural layers
Demarcate the boundaries of the lobes
Shift of fissures is best sign of lobar collapse
Minor fissure shifts up: RUL collapse
Minor fissure shifts down: RML collapse
Major fissures shift down: LL collapse
Can review in detail each of these diagrams of lobar collapse

27. Which lobes have collapsed?
Minor fissure is elevated – RUL partially collapsed
Heart has moved to right and silhouette sign of right diaphragm – indicated RLL collapse
Minor fissure is elevated – RUL partially collapsed
Heart has moved to right and silhouette sign of right diaphragm – indicated RLL collapse

28. Hilar Displacement
The left hilum is normally slightly higher than the right
Hilar depression indicates collapse of lower lobe
Hilar elevation indicates collapse of upper lobe

29. The Mediastinum A. Ascending aorta B. Aortic knob
A = ascending aorta B aortic knob C descending aorta D right heart border E superior vena cava F right tracheal wall G left heart
A ascending aorta B aortic knob C descending aorta D right heart G left heart {L left pulmonary artery and R right pulmonary artery – outside the mediastinum}
X= retrosternal clear space
A. Ascending aorta B. Aortic knob
C. Descending aorta D. R heart border
E. SVC F. R tracheal wall G. L heart
X. retrosternal clear space
Outside mediastinum:
L. L pulmonary artery
R. R pulmonary artery

30. The Mediastinum I: Anterior Mediastinum II: Middle Mediastinum
Heart
Retrosternal clear space
4 T’s
II: Middle Mediastinum
Esophagus
Arch and descending aorta
Trachea
III: Posterior Mediastinum
Paravertebral area; most masses neurogenic
Lymph nodes in all 3!
Anterior mediastinal compartment – heart and retrosternal clear space – teratoma, thymoma, thyroid, terrible lymphoma, and thoracic aorta
Middle mediastinum – esophagus, lymph nodes, arch and descending aorta, trachea
Posterior mediastinum is the paravertebral area

31. The Pleura
The posterior costophrenic angle is the deepest and only seen on the lateral film
The lateral film is more sensitive for detection of small pleural effusions
How much fluid can be seen on a radiograph?
Erect PA: 175 mL
Erect lateral: 75 mL
Decubitus: >5 mL
Supine: Several hundred mL
Anterior, posterior and lateral costophrenic angles
Erect PA = 175 mL Lateral = 75 ml decubitus = >5 mL Supine = several hundred mL

32. What do you see?
Air enters pleural space with each breath but cant escape, increasing intrapleural pressure – increased pressure depresses the diaphragm, collapses the lung, and shifts the mediastinum away
Clinical signs: rapid onset respiratory failure, decreased breath sounds, deviated trachea, JVD

33. Pneumothorax
Air enters pleural space with each breath but cant escape, increasing intrapleural pressure – increased pressure depresses the diaphragm, collapses the lung, and shifts the mediastinum away
Clinical signs: rapid onset respiratory failure, decreased breath sounds, deviated trachea, JVD

34. The Heart
The horizontal width of the heart should be less than ½ the widest internal diameter of the thorax

35. Left and Right Ventricular Enlargement
Left ventricular enlargement
Frontal: LHB moves laterally and cardiac apex inferolaterally
Lateral: LHB moves inferoposteriorly
Right ventricular enlargement
Frontal: RHB further right
Lateral: Contacts lower half of sternum (instead of lower 3rd)

36. Cephalization Enlargement of the upper lobe vessels
“Vascular redistribution”
“Kerley B” lines: interstitial edema thickening the interlobular septa causing short lines perpendicular to the pleural surface

37. Systematic approach ABCDE Airway Bones and breasts
Cardiac and costophrenic
Diaphragm
Edges and extrathoracic
Fields (lung fields and failure)
Airways, bones and breasts, cardiac and costophrenic diaphragm, edges and extrathoracic, fields lung fields and failure

38. Cases

39. RML Infiltrate

40. LUL Infiltrate

41. LLL infiltrate

42. Subtle pneumothorax

43. Young man with cancer Metal nipple markers have been placed
Is the lung abnormal: pulmonary nodule below right nipple marker where ribs cross
Right shoulder amputated: pulmonary met from osteosarcoma

44. Osteosarcoma w Pulmonary Met
Metal nipple markers have been placed
1. pulmonary nodule below right nipple marker where ribs cross
2. Right shoulder amputated: pulmonary met from osteosarcoma
Metal nipple markers have been placed
Is the lung abnormal: pulmonary nodule below right nipple marker where ribs cross
Right shoulder amputated: pulmonary met from osteosarcoma

45. Young man without symptoms
Strange cardiomediastinal shape on left - causes silhouette of left atrium ,pulmonary artery, and aortic arch
Lateral shows density in retrosternal clear space

46. Anterior Mediastinal Mass
Strange cardiomediastinal shape on left - causes silhouette of left atrium ,pulmonary artery, and aortic arch
Lateral shows density in retrosternal clear space
Strange cardiomediastinal shape on left - causes silhouette of left atrium ,pulmonary artery, and aortic arch
Lateral shows density in retrosternal clear space

47. Dyspnea with sudden CP & fever
Cardiac silhouette is enlarged; Pulmonary vessels are enlarged with cephalization and mildly indistinct
DX – mild left ventricular failure
Dx: free air under diaphragms (from perf ulcer) explains sudden chest pain and fever

48. Heart Failure and Perf Ulcer
Cardiac silhouette is enlarged; Pulmonary vessels are enlarged with cephalization and mildly indistinct
DX – mild left ventricular failure
Dx: free air under diaphragms (from perf ulcer) explains sudden chest pain and fever
Cephalization, enlarged heart, free air